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  • 1.
    Abele, H.
    et al.
    TU-Wien, Atominstitut, Austria.
    Blennow, Malin
    Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Dunne, Katherine
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Meirose, Bernhard
    Stockholm University, Faculty of Science, Department of Physics.
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohlsson, Tommy
    Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yiu, Sze-Chun
    Stockholm University, Faculty of Science, Department of Physics.
    Zou, Y.
    Department of Physics and Astronomy, Uppsala University, Sweden.
    Particle physics at the European Spallation Source2023In: Physics reports, ISSN 0370-1573, E-ISSN 1873-6270, Vol. 1023, p. 1-84Article, review/survey (Refereed)
    Abstract [en]

    Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world's brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).

  • 2.
    Abele, H.
    et al.
    National Centre for Nuclear Research, Pasteura 7, 02-093 Warsaw, Poland.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, 106 91 Stockholm.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.
    Zou, Y.
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Particle physics at the European Spallation Source2023In: Physics reports, ISSN 0370-1573, E-ISSN 1873-6270, Vol. 1023, p. 1-84Article, review/survey (Refereed)
    Abstract [en]

    Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world's brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).

  • 3. Agarwalla, S.K.
    et al.
    Akhmedov, E.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Coloma, P.
    Donini, A.
    Fernandez-Martinez, E.
    Giunti, C.
    Gomez-Cadenas, J.J.
    Gonzalez-Garcia, M.C.
    Hernandez, P.
    Huber, P.
    Laveder, M.
    Li, T.
    Longhin, A.
    Lopez-Pavon, J.
    Maltoni, M.
    Meloni, D.
    Mena, O.
    Menendez, J.
    Mezzetto, M.
    Migliozzi, P.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Orme, C.
    Pascoli, S.
    Salvado, J.
    Schwetz, T.
    Scotto-Lavina, L.
    Tang, J.
    Terranova, F.
    Winter, W.
    Zhang, H.
    EUROnu-WP6 2010 Report2012Report (Other academic)
    Abstract [en]

    This is a summary of the work done by the Working Package 6 (Physics) of the EU project "EUROnu" during the second year of activity of the project.

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  • 4.
    Ahlgren, Björn
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhou, Shun
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Comment on "Is Dark Matter with Long-Range Interactions a Solution to All Small-Scale Problems of Λ Cold Dark Matter Cosmology?"2013In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 111, no 19, p. 199001-Article in journal (Refereed)
    Download full text (pdf)
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  • 5.
    Akhmedov, Evgeny
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Hällgren, Tomas
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Konstandin, Thomas
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Stability and leptogenesis in the left-right symmetric seesaw mechanism2007In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 4, p. 022-1-022-25Article in journal (Refereed)
    Abstract [en]

    We analyze the left-right symmetric type I+II seesaw mechanism, where an eight-fold degeneracy among the mass matrices of heavy right-handed neutrinos M-R is known to exist. Using the stability property of the solutions and their ability to lead to successful baryogenesis via leptogenesis as additional criteria, we discriminate among these eight solutions and partially lift their eight-fold degeneracy. In particular, we find that viable leptogenesis is generically possible for four out of the eight solutions.

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  • 6. Akhmedov, Evgeny
    et al.
    Huber, Patrick
    Lindner, Manfred
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    T violation in neutrino oscillations in matter2001In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 608, no 02-jan, p. 394-422Article in journal (Refereed)
    Abstract [en]

    We consider the interplay of fundamental and matter-induced T violation effects in neutrino oscillations in matter. After discussing the general features of these effects we derive a simple approximate analytic expression for the T-violating probability asymmetry DeltaP(ab)(T) for three-flavour neutrino oscillations in a matter with an arbitrary density profile in terms of the two-flavour neutrino amplitudes. Explicit examples are given for the cases of a two-layer medium and for the adiabatic Emit in the general case. We then discuss implications of the obtained results for long baseline experiments. We show, in particular, that asymmetric matter effects cannot hinder the determination of the fundamental CP- and T-violating phase delta (CP) in the long baseline experiments as far as the error in this determination is larger than 1% at 99% CL. Since there are no T-violating effects in the two-flavour case, and in the limits of vanishing theta (13) or Deltam(21)(2) the three-flavour neutrino oscillations effectively reduce to the two-flavour ones, studying the T-violating asymmetries ApT ab can in principle provide us with a complementary means of measuring theta (13) and Deltam(21)(2).

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  • 7. Akhmedov, Evgeny K.
    et al.
    Johansson, Robert
    KTH, Superseded Departments (pre-2005), Physics.
    Lindner, Manfred
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    Schwetz, Thomas
    Series expansions for three-flavor neutrino oscillation probabilities in matter2004In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2004, no 04, p. 078-Article in journal (Refereed)
    Abstract [en]

    We present a number of complete sets of series expansion formulas for neutrino oscillation probabilities in matter of constant density for three flavors. In particular, we study expansions in the mass hierarchy parameter alpha = Deltam(21)(2)/Deltam(31)(2) and mixing parameter s(13) = sin theta(13) up to second order and expansions only in alpha and only in s(13) up to first order. For each type of expansion we also present the corresponding formulas for neutrino oscillations in vacuum. We perform a detailed analysis of the accuracy of the different sets of series expansion formulas and investigate which type of expansion is most accurate in different regions of the parameter space spanned by the neutrino energy E, the baseline length L, and the expansion parameters alpha and s(13). We also present the formulas for series expansions in alpha and in s(13) up to first order for the case of arbitrary matter density profiles. Furthermore, it is shown that in general all the 18 neutrino and antineutrino oscillation probabilities can be expressed through just two independent probabilities.

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  • 8. Alekou, A.
    et al.
    Baussan, E.
    Bhattacharyya, A. K.
    Kraljevic, N. B.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Bogomilov, M.
    Bolling, B.
    Bouquerel, E.
    Buchan, O.
    Burgman, A.
    Carlile, C. J.
    Cederkall, J.
    Christiansen, P.
    Collins, M.
    Morales, E. C.
    Cupiał, P.
    D’Alessi, L.
    Danared, H.
    Dancila, D.
    de André, J. P. A. M.
    Delahaye, J. P.
    Dracos, M.
    Efthymiopoulos, I.
    Ekelöf, T.
    Eshraqi, M.
    Fanourakis, G.
    Farricker, A.
    Fernandez-Martinez, E.
    Folsom, B.
    Fukuda, T.
    Gazis, N.
    Gålnander, B.
    Geralis, T.
    Ghosh, M.
    Gokbulut, G.
    Halić, L.
    Jenssen, M.
    Topaksu, A. K.
    Kildetoft, B.
    Kliček, B.
    Kozioł, M.
    Krhač, K.
    Łacny, Ł.
    Lindroos, M.
    Maiano, C.
    Marrelli, C.
    Martins, C.
    Mezzetto, M.
    Milas, N.
    Oglakci, M.
    Ohlsson, Tommy
    KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Engineering Sciences (SCI), Physics.
    Olvegård, M.
    Ota, T.
    Park, J.
    Patrzalek, D.
    Petkov, G.
    Poussot, P.
    Johansson, R.
    Rosauro-Alcaraz, S.
    Saiang, D.
    Szybiński, B.
    Snamina, J.
    Sosa, A. G.
    Stavropoulos, G.
    Stipčević, M.
    Tarkeshian, R.
    Terranova, F.
    Thomas, J.
    Tolba, T.
    Trachanas, E.
    Tsenov, R.
    Vankova-Kirilova, G.
    Vassilopoulos, N.
    Wildner, E.
    Wurtz, J.
    Zormpa, O.
    Zou, Y.
    The European Spallation Source neutrino super-beam conceptual design report2022In: The European Physical Journal Special Topics, ISSN 1951-6355, E-ISSN 1951-6401, Vol. 231, no 21, p. 3779-3955Article in journal (Refereed)
    Abstract [en]

    A design study, named ESS νSB for European Spallation Source neutrino Super Beam, has been carried out during the years 2018–2022 of how the 5 MW proton linear accelerator of the European Spallation Source under construction in Lund, Sweden, can be used to produce the world’s most intense long-baseline neutrino beam. The high beam intensity will allow for measuring the neutrino oscillations near the second oscillation maximum at which the CP violation signal is close to three times higher than at the first maximum, where other experiments measure. This will enable CP violation discovery in the leptonic sector for a wider range of values of the CP violating phase δCP and, in particular, a higher precision measurement of δCP. The present Conceptual Design Report describes the results of the design study of the required upgrade of the ESS linac, of the accumulator ring used to compress the linac pulses from 2.86 ms to 1.2 μs, and of the target station, where the 5 MW proton beam is used to produce the intense neutrino beam. It also presents the design of the near detector, which is used to monitor the neutrino beam as well as to measure neutrino cross sections, and of the large underground far detector located 360 km from ESS, where the magnitude of the oscillation appearance of νe from νμ is measured. The physics performance of the ESS νSB research facility has been evaluated demonstrating that after 10 years of data-taking, leptonic CP violation can be detected with more than 5 standard deviation significance over 70% of the range of values that the CP violation phase angle δCP can take and that δCP can be measured with a standard error less than 8° irrespective of the measured value of δCP. These results demonstrate the uniquely high physics performance of the proposed ESS νSB research facility. 

  • 9.
    Alekou, A.
    et al.
    CERN, Geneva 23, 1211, Switzerland, Geneva 23; Department of Physics and Astronomy, FREIA Division, Uppsala University, P.O. Box 516, Uppsala, 751 20, Sweden, P.O. Box 516.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, Stockholm, 106 91, Sweden, Roslagstullsbacken 21.
    Choubey, Sandhya
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, Stockholm, 106 91, Sweden, Roslagstullsbacken 21.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, Stockholm, 106 91, Sweden, Roslagstullsbacken 21.
    Zou, Y.
    Department of Physics and Astronomy, FREIA Division, Uppsala University, P.O. Box 516, Uppsala, 751 20, Sweden, P.O. Box 516.
    et al.,
    The ESSnuSB Design Study: Overview and Future Prospects2023In: Universe, E-ISSN 2218-1997, Vol. 9, no 8, article id 347Article, review/survey (Refereed)
    Abstract [en]

    ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the second maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, and the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.

  • 10.
    Alekou, A.
    et al.
    CERN, CH-1211 Geneva 23, Switzerland.;Uppsala Univ, POB 256, S-75105 Uppsala, Sweden..
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. Oskar Klein Ctr, Roslagstullsbacken 21, S-10691 Stockholm, Sweden..
    D'Alessi, L.
    Univ Strasbourg, IPHC, CNRS, IN2P3, Strasbourg, France..
    Ghosh, M.
    Rudjer Boskovic Inst, Ctr Excellence Adv Mat & Sensing Devices, Zagreb 10000, Croatia.;Univ Hyderabad, Sch Phys, Hyderabad 500046, India..
    Klicek, B.
    Rudjer Boskovic Inst, Ctr Excellence Adv Mat & Sensing Devices, Zagreb 10000, Croatia..
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. Oskar Klein Ctr, Roslagstullsbacken 21, S-10691 Stockholm, Sweden..
    Zou, Y.
    Uppsala Univ, POB 256, S-75105 Uppsala, Sweden..
    Updated physics performance of the ESSnuSB experiment2021In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 81, no 12, article id 1130Article in journal (Refereed)
    Abstract [en]

    In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of 5% for signal and 10% for background, we find that there is 10 sigma (13 sigma) CP violation discovery sensitivity for the baseline option of 540 km (360 km) at delta(CP) = +/- 90 degrees. The corresponding fraction of delta(CP )for which CP violation can be discovered at more than 5 sigma is 70%. Regarding CP precision measurements, the 1 sigma error associated with delta(CP )= 0 degrees is around 5 degrees and with delta(CP )= -90 degrees is around 14 degrees (7 degrees) for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have 3 sigma sensitivity for 540 km baseline except delta(CP) = +/- 90 degrees and 5 sigma sensitivity for 360 km baseline for all values of delta(CP). The octant of theta(23) can be determined at 30 for the values of: theta(23) > 51 degrees (theta(23) < 42 degrees and theta(23) > 49 degrees) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at 3 sigma are: 40 degrees < theta(23) < 52 degrees (42 degrees < theta(23) < 51.5 degrees) and 2.485 x 10(-3) eV(2) < Delta(2)(m31) < 2.545 x 10(-3) eV(2) (2.49x 10(-3 ) eV(2) < Delta(2)(m31) < 2.54 x 10(-3) eV(2)) for the baseline of 540 km (360 km).

  • 11. Baussan, E.
    et al.
    Blennow, Mattias
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Bogomilov, M.
    Bouquerel, E.
    Caretta, O.
    Cederkäll, J.
    Christiansen, P.
    Coloma, P.
    Cupial, P.
    Danared, H.
    Davenne, T.
    Densham, C.
    Dracos, M.
    Ekelöf, T.
    Eshraqi, M.
    Fernandez Martinez, E.
    Gaudiot, G.
    Hall-Wilton, R.
    Koutchouk, J. -P
    Lindroos, M.
    Loveridge, P.
    Matev, R.
    McGinnis, D.
    Mezzetto, M.
    Miyamoto, R.
    Mosca, L.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Öhman, H.
    Osswald, F.
    Peggs, S.
    Poussot, P.
    Ruber, R.
    Tang, J. Y.
    Tsenov, R.
    Vankova-Kirilova, G.
    Vassilopoulos, N.
    Wilcox, D.
    Wildner, E.
    Wurtz, J.
    A very intense neutrino super beam experiment for leptonic CP violation discovery based on the European spallation source linac2014In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 885, p. 127-149Article in journal (Refereed)
    Abstract [en]

    Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spoliation Source currently under construction in Lund, Sweden, to deliver, in parallel with the spoliation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spoliation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few mu s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 sigma significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 sigma if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.

  • 12.
    Beiming, Christoffer
    et al.
    KTH.
    Grönroos, Jesper
    KTH.
    Ohlsson, Tommy
    KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Phenomenological mass model for exotic hadrons and predictions for masses of non-strange dibaryons as hexaquarks2022In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 974, p. 115616-, article id 115616Article in journal (Refereed)
    Abstract [en]

    We investigate the mass spectra of exotic hadrons known as hexaquarks in the form of dibaryons. We use a phenomenological model based on an extended version of the Giirsey-Radicati mass formula for hadrons to include non-charmed baryons, charmed baryons, and non-strange dibaryons to be able to predict masses of potential dibaryon states. We perform six numerical fits of this model to input data for three different sets of masses of baryons and dibaryons. We find that the model can fit some of the data sets well, especially the sets including charmed baryons and non-strange dibaryons, and observe that the predicted mass of one of the dibaryons is close to the measured mass of the observed hexaquark candidate d * (2380) reported by the WASA-at-COSY experiment. The predicted mass of the deuteron is slightly larger than its measured mass. Finally, for the data sets including charmed baryon and non-strange dibaryon masses, we find that the predicted masses of potential dibaryon states are all in the range from 1900 MeV to 3700 MeV.

  • 13.
    Bergström, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Malinský, Michal
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Renormalization group running of neutrino parameters in the inverse seesaw model2010In: Physical Review D, ISSN 1550-7998, Vol. 81, no 11, p. 116006-Article in journal (Refereed)
    Abstract [en]

    We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.

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  • 14.
    Bergström, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Merle, Alexander
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Constraining new physics with a positive or negative signal of neutrino-less double beta decay2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2011, no 05, p. 122-Article in journal (Refereed)
    Abstract [en]

    We investigate numerically how accurately one could constrain the strengths of different short-range contributions to neutrino-less double beta decay in effective field theory. Depending on the outcome of near-future experiments yielding information on the neutrino masses, the corresponding bounds or estimates can be stronger or weaker. A particularly interesting case, resulting in strong bounds, would be a positive signal of neutrino-less double beta decay that is consistent with complementary information from neutrino oscillation experiments, kinematical determinations of the neutrino mass, and measurements of the sum of light neutrino masses from cosmological observations. The keys to more robust bounds are improvements of the knowledge of the nuclear physics involved and a better experimental accuracy.

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  • 15.
    Bergström, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Unparticle self-interactions at the Large Hadron Collider2009In: Physical Review D. Particles, fields, gravitation and cosmology, ISSN 1550-7998, Vol. 80, no 11, p. 115014-Article in journal (Refereed)
    Abstract [en]

    We investigate the effect of unparticle self-interactions at the Large Hadron Collider (LHC). Especially, we discuss the three-point correlation function, which is determined by conformal symmetry up to a constant, and study its relation to processes with four-particle final states. These processes could be used as a favorable way to look for unparticle physics, and for weak enough couplings to the standard model, even the only way. We find updated upper bounds on the cross sections for unparticle-mediated 4 gamma final states at the LHC and novel upper bounds for the corresponding 2 gamma 2l and 4l final states. The size of the allowed cross sections obtained are comparably large for large values of the scaling dimension of the unparticle sector, but they decrease with decreasing values of this parameter. In addition, we present relevant distributions for the different final states, enabling the possible identification of the unparticle scaling dimension if there was to be a large number of events of such final states at the LHC.

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  • 16.
    Bergström, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Threshold effects on renormalization group running of neutrino parameters in the low-scale seesaw model2011In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 698, no 4, p. 297-305Article in journal (Refereed)
    Abstract [en]

    We show that, in the low-scale type-I seesaw model, renormalization group running of neutrino parameters may lead to significant modifications of the leptonic mixing angles in view of so-called seesaw threshold effects. Especially, we derive analytical formulas for radiative corrections to neutrino parameters in crossing the different seesaw thresholds, and show that there may exist enhancement factors efficiently boosting the renormalization group running of the leptonic mixing angles. We find that, as a result of the seesaw threshold corrections to the leptonic mixing angles, various flavor symmetric mixing patterns (e.g., bi-maximal and tri-bimaximal mixing patterns) can be easily accommodated at relatively low energy scales, which is well within the reach of running and forthcoming experiments (e.g., the LHC).

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  • 17. Bergström, Lars
    et al.
    Botner, OlgaCarlson, PerHulth, Per OlofOhlsson, TommyKTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Neutrino Physics: Proceedings of Nobel Symposium 1292006Conference proceedings (editor) (Refereed)
    Abstract [en]

    PREFACE

    Nobel Symposium 129 on Neutrino Physics was held at Haga Slott in Enköping, Sweden during August 19–24, 2004. Invited to the symposium were around 40 globally leading researchers in the field of neutrino physics, both experimental and theoretical. In addition to these participants, some 30 local researchers and graduate students participated in the symposium.

    The dominant theme of the lectures was neutrino oscillations, which after several years were recently verified by results from the Super-Kamiokande detector in Kamioka, Japan and the SNO detector in Sudbury, Canada. Discussion focused especially on effects of neutrino oscillations derived from the presence of matter and the fact that three different neutrinos exist. Since neutrino oscillations imply that neutrinos have mass, this is the first experimental observation that fundamentally deviates from the standard model of particle physics. This is a challenge to both theoretical and experimental physics. The various oscillation parameters will be determined with increased precision in new, specially designed experiments. Theoretical physics is working intensively to insert the knowledge that neutrinos have mass into the theoretical models that describe particle physics. It will probably turn out that the discovery of neutrino oscillations signifies a breakthrough in the description of the very smallest constituents of matter. The lectures provided a very good description of the intensive situation in the field right now. The topics discussed also included mass models for neutrinos, neutrinos in extra dimensions as well as the `seesaw mechanism', which provides a good description of why neutrino masses are so small.

    Also discussed, besides neutrino oscillations, was the new field of neutrino astronomy. Among the questions that neutrino astronomy hopes to answer are what the dark matter in the Universe consists of and where cosmic radiation at extremely high energies comes from. For this purpose, large neutrino telescopes are built deep in the Antarctic ice, in the Baikal Lake, and in the Mediterranean Sea.

    Among prominent unanswered questions, highlighted as one of the most important, was whether neutrinos are Dirac or Majorana particles. By studying neutrino double beta decay, researchers hope to answer this question, but it will put very large demands on detectors.

    The programme also included ample time for lively and valuable discussions, which cannot normally be held at ordinary conferences.

    The symposium concluded with a round-table discussion, where participants discussed the future of neutrino physics.Without a doubt, neutrino physics today is moving toward a very exciting and interesting period.

    An important contribution to the success of the symposium was the wonderful setting that the Haga Slott manor house hotel and conference center offered to the participants.

  • 18. Bilenky, Samoil M.
    et al.
    Freund, Martin
    Lindner, Manfred
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    Winter, Walter
    Tests of CPT invariance at neutrino factories2002In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 65, no 7, p. 073024-1-073024-6Article in journal (Refereed)
    Abstract [en]

    We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, such as could be induced by physics beyond the standard model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences; we found, for example, that the sensitivity \m(3)-(m) over bar (3)\less than or similar to1.9x10(-4) eV could be achieved.

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  • 19.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Choubey, Sandhya
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Pramanik, D.
    Raut, Sushant K.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    A combined study of source, detector and matter non-standard neutrino interactions at DUNE2016In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2016, no 8, article id 90Article in journal (Refereed)
    Abstract [en]

    We simultaneously investigate source, detector and matter non-standard neutrino interactions at the proposed DUNE experiment. Our analysis is performed using a Markov Chain Monte Carlo exploring the full parameter space. We find that the sensitivity of DUNE to the standard oscillation parameters is worsened due to the presence of non-standard neutrino interactions. In particular, there are degenerate solutions in the leptonic mixing angle θ23 and the Dirac CP-violating phase δ. We also compute the expected sensitivities at DUNE to the non-standard interaction parameters. We find that the sensitivities to the matter non-standard interaction parameters are substantially stronger than the current bounds (up to a factor of about 15). Furthermore, we discuss correlations between the source/detector and matter non-standard interaction parameters and find a degenerate solution in θ23. Finally, we explore the effect of statistics on our results.

  • 20.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Choubey, Sandhya
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics. Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad, India.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Raut, Sushant K.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Exploring source and detector non-standard neutrino interactions at ESS nu SB2015In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, article id 096Article in journal (Refereed)
    Abstract [en]

    We investigate source and detector non-standard neutrino interactions at the proposed ESS nu SB experiment. We analyze the effect of non-standard physics at the probability level, the event-rate level and by a full computation of the ESS nu SB setup. We find that the precision measurement of the leptonic mixing angle theta(23) at ESS nu SB is robust in the presence of non-standard interactions, whereas that of the leptonic CP-violating phase delta is worsened at most by a factor of two. We compute sensitivities to all the relevant source and decector non-standard interaction parameters and find that the sensitivities to the parameters epsilon(s)(mu e) and epsilon(d)(mu e) are comparable to the existing limits in a realistic scenario, while they improve by a factor of two in an optimistic scenario. Finally, we show that the absence of a near detector compromises the sensitivity of ESS nu SB to non-standard interactions.

  • 21.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Edsjö, Joakim
    Fysikum, Stockholm University.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Neutrinos from WIMP annihilations in the Sun including neutrino oscillations2011In: The Proceedings of the 22nd International Conference on Neutrino Physics and Astrophysics / [ed] Geoffrey Mills, Steve Elliott, Terrence Goldman, and Thomas Bowles, Elsevier, 2011, Vol. 221, p. 37-38Conference paper (Refereed)
    Abstract [en]

    The prospects to detect neutrinos from the Sun arising from dark matter annihilations in the core of the Sun are reviewed. Emphasis is placed on new work investigating the effects of neutrino oscillations on the expected neutrino fluxes.

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  • 22.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Edsjö, Joakim
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Neutrinos from WIMP annihilations in the Sun including neutrino oscillations2006In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T127, p. 19-21Article in journal (Refereed)
    Abstract [en]

    The prospects for detecting neutrinos from the Sun arising from dark matter annihilations in the core of the Sun are reviewed. Emphasis is placed on new work investigating the effects of neutrino oscillations on the expected neutrino fluxes.

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  • 23.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Edsjö, Joakim
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Neutrinos from WIMP annihilations obtained using a full three-flavor Monte Carlo approach2008In: Journal of Cosmology and Astroparticle Physics, E-ISSN 1475-7516, Vol. 2008, no 01, p. 021-Article in journal (Refereed)
    Abstract [en]

    Weakly interacting massive particles (WIMPs) are one of the main candidates for making up the dark matter in the Universe. If these particles make up the dark matter, then they can be captured by the Sun or the Earth, sink to the respective cores, annihilate, and produce neutrinos. Thus, these neutrinos can be a striking dark matter signature at neutrino telescopes looking towards the Sun and/or the Earth. Here, we improve previous analyses on computing the neutrino yields from WIMP annihilations in several respects. We include neutrino oscillations in a full three-flavor framework as well as all effects from neutrino interactions on the way through the Sun (absorption, energy loss, and regeneration from tau decays). In addition, we study the effects of non-zero values of the mixing angle theta(13) as well as the normal and inverted neutrino mass hierarchies. Our study is performed in an event-based setting which makes these results very useful both for theoretical analyses and for building a neutrino telescope Monte Carlo code. All our results for the neutrino yields, as well as our Monte Carlo code, are publicly available. We find that the yield of muontype neutrinos from WIMP annihilations in the Sun is enhanced or suppressed, depending on the dominant WIMP annihilation channel. This effect is due to an effective favor mixing caused by neutrino oscillations. For WIMP annihilations inside the Earth, the distance from source to detector is too small to allow for any significant amount of oscillations at the neutrino energies relevant for neutrino telescopes.

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  • 24.
    Blennow, Mattias
    et al.
    Max-Planck-Institut für Physik.
    Edsjö, Joakim
    Department of Physics, Stockholm University.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    WIMP neutrinos from the Sun and the Earth2008In: : idm2008, SISSA , 2008, p. 4p-Conference paper (Refereed)
    Abstract [en]

    We discuss the propagation treatment of the indirect dark matter detection using WIMP annihilations in the Sun and the Earth. In particular, we focus on treating neutrino interactions and oscillations in a consistent framework, including tau neutrino regeneration and a full three-flavor neutrino oscillation framework. We also discuss the equivalence of using a Monte Carlo approach - suited for inclusion in neutrino telescope Monte Carlos - and the density matrix formalism.

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  • 25.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics.
    Ghosh, Manojit
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Titov, Arsenii
    Probing lepton flavor models at future neutrino experiments2020In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 102, no 11, article id 115004Article in journal (Refereed)
    Abstract [en]

    Non-Abelian discrete symmetries provide an interesting opportunity to address the flavor puzzle in the lepton sector. However, the number of currently viable models based on such symmetries is rather large. High-precision measurements of the leptonic mixing parameters by future neutrino experiments, including ESSnuSB, T2HK, DUNE, and JUNO, will be crucial to test such models. We show that the complementarity among these experiments offers a powerful tool for narrowing down this broad class of lepton flavor models.

  • 26.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Theoretical Particle Physics. Univ Autonoma Madrid, Dept Fis Teor, IFT UAM, CSIC, Madrid 28049, Spain.;Univ Autonoma Madrid, Inst Fis Teor, IFT UAM, CSIC, Madrid 28049, Spain.;AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ghosh, Manojit
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Sch Engn Sci, KTH Royal Inst Technol, Dept Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;Univ Iceland, Sci Inst, Dunhaga 3, IS-107 Reykjavik, Iceland..
    Titov, Arsenii
    Univ Padua, Dipartimento Fis & Astron G Galilei, Via Francesco Marzolo 8, I-35131 Padua, Italy.;INFN, Sez Padova, Via Francesco Marzolo 8, I-35131 Padua, Italy..
    Testing lepton flavor models at ESSnuSB2020In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 7, article id 014Article in journal (Refereed)
    Abstract [en]

    We review and investigate lepton flavor models, stemming from discrete non- Abelian flavor symmetries, described by one or two free model parameters. First, we confront eleven one- and seven two-parameter models with current results on leptonic mixing angles from global fits to neutrino oscillation data. We find that five of the one- and five of the two-parameter models survive the confrontation test at 3 sigma. Second, we investigate how these ten one- and two-parameter lepton flavor models may be discriminated at the proposed ESSnuSB experiment in Sweden. We show that the three one-parameter models that predict sin delta(CP) = 0 can be distinguished from those two that predict vertical bar sin delta(CP)vertical bar = 1 by at least 7 sigma. Finally, we find that three of the five one-parameter models can be excluded by at least 5 sigma and two of the one-parameter as well as at most two of the five two-parameter models can be excluded by at least 3 sigma with ESSnuSB if the true values of the leptonic mixing parameters remain close to the present best-fit values.

  • 27.
    Blennow, Mattias
    et al.
    Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Neutrinos from Kaluza-Klein dark matter in the Sun2010In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, Vol. 2010, no 01, p. 018-Article in journal (Refereed)
    Abstract [en]

    We investigate indirect neutrino signals from annihilations of Kaluza-Klein dark matter in the Sun. Especially, we examine a five- as well as a six-dimensional model, and allow for the possibility that boundary localized terms could affect the spectrum to give different lightest Kaluza-Klein particles, which could constitute the dark matter. The dark matter candidates that are interesting for the purpose of indirect detection of neutrinos are the first Kaluza-Klein mode of the U(1) gauge boson and the neutral component of the SU(2) gauge bosons. Using the DarkSUSY and WimpSim packages, we calculate muon fluxes at an Earth-based neutrino telescope, such as IceCube. For the five-dimensional model, the results hat we obtained agree reasonably well with the results that have previously been presented in the literature, whereas for the six-dimensional model, we find that, at tree-level, the results are the same as for the five-dimensional model. Finally, if the first Kaluza-Klein mode of the U(1) gauge boson constitutes the dark matter, IceCube can constrain the parameter space. However, in the case that the neutral component of the SU(2) gauge bosons is the LKP, the signal is too weak to be observed.

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  • 28.
    Blennow, Mattias
    et al.
    Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Non-unitary neutrino mixing from an extra-dimensional seesaw model2010Manuscript (preprint) (Other academic)
    Abstract [en]

    We study the generation of light neutrino masses in an extra-dimensional model, where right-handed neutrinos are allowed to propagate in the extra dimension, while the Standard model (SM) particles are confined to a brane. Motivated by the fact that extra-dimensional models are non-renormalizable, we truncate the Kaluza–Klein (KK) towers at a maximal KK index. The structure of the bulk Majorana mass term, motivated by the Sherk–Schwarz mechanism, implies that the right-handed KK neutrinos pair to form Dirac neutrinos, except for a number of unpaired Majorana neutrinos at the top of each tower. These heavy Majorana neutrinos are the only sources of lepton number breaking in the model, and similarly to the type-I seesaw mechanism, they naturally generate small masses for the left-handed neutrinos. The lower KK modes mix with the light neutrinos, and the mixing effects are not suppressed with respect to the light neutrino masses. Compared to conventional fermionic seesaw models, the non-unitary effects induced by such mixing are quite significant. We study the signals of this model at the Large Hadron Collider (LHC), and find that the current bounds on the non-unitarity parameters are strong enough to exclude an observation.

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  • 29. Blennow, Mattias
    et al.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    Renormalization group running of the neutrino mass operator in extra dimensions2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2011, no 04, p. 052-Article in journal (Refereed)
    Abstract [en]

    We study the renormalization group (RG) running of the neutrino masses and the leptonic mixing parameters in two different extra-dimensional models, namely, the Universal Extra Dimensions (UED) model and a model, where the Standard Model (SM) bosons probe an extra dimension and the SM fermions are confined to a four-dimensional brane. In particular, we derive the beta function for the neutrino mass operator in the UED model. We also rederive the beta function for the charged-lepton Yukawa coupling, and confirm some of the existing results in the literature. The generic features of the RG running of the neutrino parameters within the two models are analyzed and, in particular, we observe a power-law behavior for the running. We note that the running of the leptonic mixing angle theta(12) can be sizable, while the running of theta(23) and theta(13) is always negligible. In addition, we show that the tri-bimaximal and the bimaximal mixing patterns at a high-energy scale are compatible with low-energy experimental data, while a tri-small mixing pattern is not. Finally, we perform a numerical scan over the low-energy parameter space to infer the high-energy distribution of the parameters. Using this scan, we also demonstrate how the high-energy theta(12) is correlated with the smallest neutrino mass and the Majorana phases.

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  • 30. Blennow, Mattias
    et al.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    RG running in a minimal UED model in light of recent LHC Higgs mass bounds2012In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 712, no 4-5, p. 419-424Article in journal (Refereed)
    Abstract [en]

    We study how the recent ATLAS and CMS Higgs mass bounds affect the renormalization group running of the physical parameters in universal extra dimensions. Using the running of the Higgs self-coupling constant, we derive bounds on the cutoff scale of the extra-dimensional theory itself. We show that the running of physical parameters, such as the fermion masses and the CKM mixing matrix, is significantly restricted by these bounds. In particular, we find that the running of the gauge couplings cannot be sufficient to allow gauge unification at the cutoff scale.

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  • 31. Blennow, Mattias
    et al.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Signatures from an extra-dimensional seesaw model2010In: Physical Review D, ISSN 1550-7998, Vol. 82, no 4, p. 045023-Article in journal (Refereed)
    Abstract [en]

    We study the generation of small neutrino masses in an extra-dimensional model, where singlet fermions are allowed to propagate in the extra dimension, while the standard model particles are confined to a brane. Motivated by the fact that extra-dimensional models are nonrenormalizable, we truncate the Kaluza-Klein towers at a maximal Kaluza-Klein number. This truncation, together with the structure of the bulk Majorana mass term, motivated by the Sherk-Schwarz mechanism, implies that the Kaluza-Klein modes of the singlet fermions pair to form Dirac fermions, except for a number of unpaired Majorana fermions at the top of each tower. These heavy Majorana fermions are the only sources of lepton number breaking in the model, and similarly to the type-I seesaw mechanism, they naturally generate small masses for the left-handed neutrinos. The lower Kaluza-Klein modes mix with the light neutrinos, and the mixing effects are not suppressed with respect to the light-neutrino masses. Compared to conventional fermionic seesaw models, such mixing can be more significant. We study the signals of this model at the Large Hadron Collider, and find that the current low-energy bounds on the nonunitarity of the leptonic mixing matrix are strong enough to exclude an observation.

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  • 32.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Meloni, Davide
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Terranova, Francesco
    Westerberg, Mattias
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Non-standard interactions using the OPERA experiment2008In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 56, no 4, p. 529-536Article in journal (Refereed)
    Abstract [en]

    We investigate the implications of non-standard interactions on neutrino oscillations in the OPERA experiment. In particular, we study the non-standard interaction parameter epsilon(mu tau) . We show that the OPERA experiment has a unique opportunity to reduce the allowed region for this parameter compared with other experiments such as the MINOS experiment, mostly due to the higher neutrino energies in the CNGS beam compared to the NuMI beam. We find that OPERA is mainly sensitive to a combination of standard and non-standard parameters and that a resulting anti-resonance effect could suppress the expected number of events. Furthermore, we show that running OPERA for five years each with neutrinos and anti-neutrinos would help in resolving the degeneracy between the standard parameters and epsilon(mu tau) . This scenario is significantly better than the scenario with a simple doubling of the statistics by running with neutrinos for ten years.

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  • 33. Blennow, Mattias
    et al.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Approximative two-flavor framework for neutrino oscillations with nonstandard interactions2008In: Physical Review D, ISSN 1550-7998, Vol. 78, no 9, p. 093002-1-093002-9Article in journal (Refereed)
    Abstract [en]

    In this paper, we develop approximative two-flavor neutrino oscillation formulas including subleading nonstandard interaction effects. Especially, the limit when the small mass-squared difference approaches zero is investigated. The approximate formulas are also tested against numerical simulations in order to determine their accuracy and they will probably be most useful in the GeV energy region, which is the energy region where most upcoming neutrino oscillation experiments will be operating. Naturally, it is important to have analytical formulas in order to interpret the physics behind the degeneracies between standard and nonstandard parameters.

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  • 34.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Effective neutrino mixing and oscillations in dense matter2005In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 609, no 3-4, p. 330-338Article in journal (Refereed)
    Abstract [en]

    We investigate the effective case of two-flavor neutrino oscillations in infinitely dense matter by using a perturbative approach. We begin by briefly summarizing the conditions for the three-flavor neutrino oscillation probabilities to take on the same form as the corresponding two-flavor probabilities. Then, we proceed with the infinitely dense matter calculations. Finally, we study the validity of the approximation of infinitely dense matter when the effective matter potential is large, but not infinite, this is done by using both analytic and numeric methods.

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  • 35.
    Blennow, Mattias
    et al.
    KTH, Superseded Departments (pre-2005), Physics.
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    Exact series solution to the two flavor neutrino oscillation problem in matter2004In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 45, no 11, p. 4053-4063Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a real nonlinear differential equation for the two flavor neutrino oscillation problem in matter with an arbitrary density profile. We also present an exact series solution to this nonlinear differential equation. In addition, we investigate numerically the convergence of this solution for different matter density profiles such as constant and linear profiles as well as the Preliminary Reference Earth Model describing the Earth's matter density profile. Finally, we discuss other methods used for solving the neutrino flavor evolution problem.

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  • 36.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Skrotzki, Julian
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Effects of non-standard interactions in the MINOS experiment2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 660, no 5, p. 522-528Article in journal (Refereed)
    Abstract [en]

    We investigate the effects of non-standard interactions on the determination of the neutrino oscillation parameters Delta m(31)(2), theta(23), and theta(13) in the MINOS experiment. We show that adding non-standard interactions to the analysis lead to an extension of the allowed parameter space to larger values of Delta m(31)(2) and smaller theta(23), and basically removes all predictability for theta(13). In addition, we discuss the sensitivities to the non-standard interaction parameters of the MINOS experiment alone. In particular, we examine the degeneracy between theta(13) and the non-standard interaction parameter epsilon(e tau). We find that this degeneracy is responsible for the removal of the theta(13) predictability and that the possible bound on vertical bar epsilon(e tau)vertical bar is competitive with direct bounds only if a more stringent external bound on theta(13) is applied.

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  • 37.
    Blennow, Mattias
    et al.
    KTH, Superseded Departments (pre-2005), Physics.
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    Snellman, Håkan
    KTH, Superseded Departments (pre-2005), Physics.
    Day-night effect in solar neutrino oscillations with three flavors2004In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 69, no 7, p. 073006-1-073006-9Article in journal (Refereed)
    Abstract [en]

    We investigate the effects of a nonzero leptonic mixing angle theta(13) on the solar neutrino day-night asymmetry. Using a constant matter density profile for the Earth and well-motivated approximations, we derive analytical expressions for the nu(e) survival probabilities for solar neutrinos arriving directly at the detector and for solar neutrinos which have passed through the Earth. Furthermore, we numerically study the effects of a nonzero theta(13) on the day-night asymmetry at detectors and find that they are small. Finally, we show that if the uncertainties in the parameters theta(12) and Deltam(2) as well as the uncertainty in the day-night asymmetry itself were much smaller than they are today, this effect could, in principle, be used to determine theta(13).

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  • 38.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Snellman, Håkan
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Solar Neutrino Day-Night Effect2005In: NEUTRINO 2004 / [ed] Jacques Dumarchez, Thomas Patzak, François Vannucci, Elsevier Science B.V. , 2005, p. 578-578Conference paper (Refereed)
    Abstract [en]

    We summarize the results of Ref. [M. Blennow, T. Ohlsson and H. Snellman, Phys. Rev. D 69 (2004) 073006, hep-ph/0311098] in which we determine the effects of three flavor mixing on the day-night asymmetry in the flux of solar neutrinos. Analytic methods are used to determine the difference in the day and night solar electron neutrino survival probabilites and numerical methods are used to determine the effect of three flavor mixing at detectors.

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  • 39.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Winter, Walter
    School of Natural Sciences, Institute for Advanced Study, Princeton, United States.
    Damping signatures in future neutrino oscillation experiments2005In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2005, no 06, p. 049-Article in journal (Refereed)
    Abstract [en]

    We discuss the phenomenology of damping signatures in the neutrino oscillation probabilities, where either the oscillating terms or the probabilities can be damped. This approach is a possibility for tests of damping effects in future neutrino oscillation experiments, where we mainly focus on reactor and long-baseline experiments. We extensively motivate different damping signatures due to small corrections by neutrino decoherence, neutrino decay, oscillations into sterile neutrinos, or other mechanisms, and classify these signatures according to their energy ( spectral) dependencies. We demonstrate, at the example of short baseline reactor experiments, that damping can severely alter the interpretation of results, e. g., it could fake a value of sin(2)(2 theta(13)) smaller than the one provided by Nature. In addition, we demonstrate how a neutrino factory could constrain different damping models with emphasis on how these different models could be distinguished, i.e., how easily the actual type of effect could be identified. We find that the damping models cluster in different categories, which can be much better distinguished from each other than models within the same cluster.

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  • 40.
    Blennow, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Winter, Walter
    School of Natural Sciences, Institute for Advanced Study, Princeton, United States.
    Non-standard Hamiltonian effects on neutrino oscillations2007In: The European Physical Journal C, ISSN 1434-6044, Vol. 49, no 4, p. 1023-1039Article in journal (Refereed)
    Abstract [en]

    We investigate non-standard Hamiltonian effects on neutrino oscillations, which are effective additional contributions to the vacuum or matter Hamiltonian. Since these effects can enter in either the flavor or mass basis, we develop an understanding of the difference between these bases representing the underlying theoretical model. In particular, the simplest of these effects are classified as "pure" flavor or mass effects, where the appearance of such a "pure" effect can be quite plausible as a leading non-standard contribution from theoretical models. Compared to earlier studies investigating particular effects, we aim for a top-down classification of a possible "new physics" signature at future long-baseline neutrino oscillation precision experiments. We develop a general framework for such effects with two neutrino flavors and discuss the extension to three neutrino flavors, and we demonstrate the challenges for a neutrino factory to distinguish the theoretical origin of these effects with a numerical example as well. We find how the precision measurements of neutrino oscillation parameters can be altered by non-standard effects alone (not including non-standard interactions in the creation and detection processes) and that the non-standard effects on Hamiltonian level can be distinguished from other non-standard effects (such as neutrino decoherence and decay) if we consider the specific imprint of the effects on the energy spectra of several different oscillation channels at a neutrino factory.

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  • 41.
    Bonnevier, Johan
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Melbéus, Henrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Merle, Alexander
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Monoenergetic gamma rays from nonminimal Kaluza-Klein dark matter annihilations2012In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 85, no 4, p. 043524-Article in journal (Refereed)
    Abstract [en]

    We investigate monoenergetic gamma-ray signatures from annihilations of dark matter comprised of Z(1), the first Kaluza-Klein (KK) excitation of the Z boson in a nonminimal universal extra dimensions (UED) model. The self interactions of the non-Abelian Z(1) gauge boson give rise to a large number of contributing Feynman diagrams that do not exist for annihilations of the Abelian gauge boson B-1, which is the standard Kaluza-Klein dark matter (KKDM) candidate. We find that the annihilation rate is indeed considerably larger for the Z(1) than for the B-1. Even though relic density calculations indicate that the mass of the Z(1) should be larger than the mass of the B-1, the predicted monoenergetic gamma fluxes are of the same order of magnitude. We compare our results to existing experimental limits, as well as to future sensitivities, for image air Cherenkov telescopes, and we find that the limits are reached already with a moderately large boost factor. The realistic prospects for detection depend on the experimental energy resolution.

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  • 42.
    Boucenna, Sofiane M.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.
    Kühnel, Florian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden;Univ Iceland, Sci Inst, Dunhaga 3, IS-107 Reykjavik, Iceland.
    Visinelli, Luca
    AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;NORDITA, AlbaNova Univ Ctr, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden.
    Novel constraints on mixed dark-matter scenarios of primordial black holes and WIMPs2018In: Journal of Cosmology and Astroparticle Physics, E-ISSN 1475-7516, no 7, article id 003Article in journal (Refereed)
    Abstract [en]

    We derive constraints on mixed dark-matter scenarios consisting of primordial black holes (PBHs) and weakly interacting massive particles (WIMPs). In these scenarios, we expect a density spike of the WIMPs that are gravitationally bound to the PBHs, which results in an enhanced annihilation rate and increased indirect detection prospects. We show that such scenarios provide strong constraints on the allowed fraction of PBHs that constitutes the dark matter, depending on the WIMP mass m(x) and the velocity-averaged annihilation cross-section <sigma v >. For the standard scenario with m(x) = 100 GeV and <sigma v > = 3 x 10(-26) cm(3)/s, we derive bounds that are stronger than all existing bounds for PBHs with masses 10(-12) M-circle dot less than or similar to M-BH less than or similar to 10(4) where M-circle dot, is the solar mass, and mostly so by several orders of magnitude.

  • 43.
    Boucenna, Sofiane M.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;Univ Iceland, Sci Inst, Dunhaga 3, IS-107 Reykjavik, Iceland..
    Pernow, Marcus
    KTH, School of Engineering Sciences (SCI), Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    A minimal non-supersymmetric SO(10) model with Peccei-Quinn symmetry2019In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 792, p. 251-257Article in journal (Refereed)
    Abstract [en]

    We present a minimal non-supersymmetric SO(10) GUT breaking directly to the Standard Model gauge group. Precise gauge coupling unification is achieved due to the presence of two color-octet scalars, one of which is accessible to LHC searches. Proton lifetime is predicted to be below 4.5 x 10(34) years, which is within the projected five-year sensitivity of the proposed Hyper-Kamiokande experiment. We find that the Standard Model observables are reproduced to a reasonable accuracy in a numerical fit, which also predicts the unknown neutrino parameters. Finally, the two scalar representations stabilize the electroweak vacuum and the dark matter is comprised of axions.

  • 44.
    Choubey, Sandhya
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics. Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad, India.
    Ghosh, Anushree
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Tiwari, D.
    Neutrino physics with non-standard interactions at INO2015In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2015, no 12, p. 1-22Article in journal (Refereed)
    Abstract [en]

    Abstract: Non-standard neutrino interactions (NSI) involved in neutrino propagation inside Earth matter could potentially alter atmospheric neutrino fluxes. In this work, we look at the impact of these NSI on the signal at the ICAL detector to be built at the India-based Neutrino Observatory (INO). We show how the sensitivity to the neutrino mass hierarchy of ICAL changes in the presence of NSI. The mass hierarchy sensitivity is shown to be rather sensitive to the NSI parameters ϵeμ and ϵeτ , while the dependence on ϵμτ and ϵτ τ is seen to be very mild, once the χ2 is marginalised over oscillation and NSI parameters. If the NSI are large enough, the event spectrum at ICAL is expected to be altered and this can be used to discover new physics. We calculate the lower limit on NSI parameters above which ICAL could discover NSI at a given C.L. from 10 years of data. If NSI were too small, the null signal at ICAL can constrain the NSI parameters. We give upper limits on the NSI parameters at any given C.L. that one is expected to put from 10 years of running of ICAL. Finally, we give C.L. contours in the NSI parameter space that is expected to be still allowed from 10 years of running of the experiment.

  • 45.
    Choubey, Sandhya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ghosh, Manojit
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;Rudjer Boskovic Inst, Ctr Excellence Adv Mat & Sensing Devices, Zagreb 10000, Croatia..
    Kempe, Daniel
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden.;Univ Iceland, Sci Inst, Dunhaga 3, IS-107 Reykjavik, Iceland..
    Exploring invisible neutrino decay at ESSnuSB2021In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2021, no 5, article id 133Article in journal (Refereed)
    Abstract [en]

    We explore invisible neutrino decay in which a heavy active neutrino state decays into a light sterile neutrino state and present a comparative analysis of two baseline options, 540 km and 360 km, for the ESSnuSB experimental setup. Our analysis shows that ESSnuSB can put a bound on the decay parameter tau (3)/m(3) = 2.64 (1.68) x 10(-11) s/eV for the baseline option of 360 (540) km at 3 sigma. The expected bound obtained for 360 km is slightly better than the corresponding one of DUNE for a charged current (CC) analysis. Furthermore, we show that the capability of ESSnuSB to discover decay, and to measure the decay parameter precisely, is better for the baseline option of 540 km than that of 360 km. Regarding effects of decay in delta (CP) measurements, we find that in general the CP violation discovery potential is better in the presence of decay. The change in CP precision is significant if one assumes decay in data but no decay in theory.

  • 46.
    Choubey, Sandhya
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics. Harish-Chandra Research Institute, India .
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Bounds on non-standard neutrino interactions using PINGU2014In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 739, p. 357-364Article in journal (Refereed)
    Abstract [en]

    We investigate the impact of non-standard neutrino interactions (NSIs) on atmospheric neutrinos using the proposed PINGU experiment. In particular, we focus on the matter NSI parameters epsilon(mu tau) and vertical bar epsilon(tau tau)-epsilon(mu mu)vertical bar that have previously been constrained by the Super-Kamiokande experiment. First, we present approximate analytical formulas for the difference of the muon neutrino survival probability with and without the above-mentioned NSI parameters. Second, we calculate the atmospheric neutrino events at PINGU in the energy range (2-100) GeV, which follow the trend outlined on probability level. Finally, we perform a statistical analysis of PINGU. Using three years of data, we obtain bounds from PINGU given by -0.0043 (-0.0048) < epsilon(mu tau) < 0.0047 (0.0046) and -0.03 (-0.016) < epsilon(tau tau) < 0.017 (0.032) at 90% confidence level for normal (inverted) neutrino mass hierarchy, which improve the Super-Kamiokande bounds by one order of magnitude. In addition, we show the expected allowed contour region in the epsilon-ettplane if NSIs exist in Nature and the result suggests that there is basically no correlation between epsilon(mu tau) and epsilon(tau tau).

  • 47.
    de Woul, Jonas
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Merle, Alexander
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Establishing analogies between the physics of extra dimensions and carbon nanotubes2012In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 714, no 1, p. 44-47Article in journal (Refereed)
    Abstract [en]

    We point out a conceptual analogy between the physics of extra spatial dimensions and the physics of carbon nanotubes which arises for principle reasons, although the corresponding energy scales are at least ten orders of magnitude apart. For low energies, one can apply the Kaluza-Klein description to both types of systems, leading to two completely different but consistent interpretations of the underlying physics. In particular, we discuss in detail the Kaluza-Klein description of armchair and zig-zag carbon nanotubes. Furthermore, we describe how certain experimental results for carbon nanotubes could be re-interpreted in terms of the Kaluza-Klein description. Finally, we present ideas for new measurements that could allow to probe concepts of models with extra spatial dimensions in table-top experiments, providing further links between condensed matter and particle physics.

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  • 48. Edgecock, T. R.
    et al.
    Caretta, O.
    Davenne, T.
    Densam, C.
    Fitton, M.
    Kelliher, D.
    Loveridge, P.
    Machida, S.
    Prior, C.
    Rogers, C.
    Rooney, M.
    Thomason, J.
    Wilcox, D.
    Wildner, E.
    Efthymiopoulos, I.
    Garoby, R.
    Gilardoni, S.
    Hansen, C.
    Benedetto, E.
    Jensen, E.
    Kosmicki, A.
    Martini, M.
    Osborne, J.
    Prior, G.
    Stora, T.
    Mendonca, T. Melo
    Vlachoudis, V.
    Waaijer, C.
    Cupial, P.
    Chance, A.
    Longhin, A.
    Payet, J.
    Zito, M.
    Baussan, E.
    Bobeth, C.
    Bouquerel, E.
    Dracos, M.
    Gaudiot, G.
    Lepers, B.
    Osswald, F.
    Poussot, P.
    Vassilopoulos, N.
    Wurtz, J.
    Zeter, V.
    Bielski, J.
    Kozien, M.
    Lacny, L.
    Skoczen, B.
    Szybinski, B.
    Ustrycka, A.
    Wroblewski, A.
    Marie-Jeanne, M.
    Balint, P.
    Fourel, C.
    Giraud, J.
    Jacob, J.
    Lamy, T.
    Latrasse, L.
    Sortais, P.
    Thuillier, T.
    Mitrofanov, S.
    Loiselet, M.
    Keutgen, Th
    Delbar, Th
    Debray, F.
    Trophine, C.
    Veys, S.
    Daversin, C.
    Zorin, V.
    Izotov, I.
    Skalyga, V.
    Burt, G.
    Dexter, A. C.
    Kravchuk, V. L.
    Marchi, T.
    Cinausero, M.
    Gramegna, F.
    De Angelis, G.
    Prete, G.
    Collazuol, G.
    Laveder, M.
    Mazzocco, M.
    Mezzetto, M.
    Signorini, C.
    Vardaci, E.
    Di Nitto, A.
    Brondi, A.
    La Rana, G.
    Migliozzi, P.
    Moro, R.
    Palladino, V.
    Gelli, N.
    Berkovits, D.
    Hass, M.
    Hirsh, T. Y.
    Schaumann, M.
    Stahl, A.
    Wehner, J.
    Bross, A.
    Kopp, J.
    Neuffer, D.
    Wands, R.
    Bayes, R.
    Laing, A.
    Soler, P.
    Agarwalla, S. K.
    Cervera Villanueva, A.
    Donini, A.
    Ghosh, T.
    Gomez Cadenas, J. J.
    Hernandez, P.
    Martin-Albo, J.
    Mena, O.
    Burguet-Castell, J.
    Agostino, L.
    Buizza-Avanzini, M.
    Marafini, M.
    Patzak, T.
    Tonazzo, A.
    Duchesneau, D.
    Mosca, L.
    Bogomilov, M.
    Karadzhov, Y.
    Matev, R.
    Tsenov, R.
    Akhmedov, E.
    Blennow, M.
    Lindner, M.
    Schwetz, T.
    Fernandez Martinez, E.
    Maltoni, M.
    Menendez, J.
    Giunti, C.
    Gonzalez Garcia, M. C.
    Salvado, J.
    Coloma, P.
    Huber, P.
    Li, T.
    Pavon, J. Lopez
    Orme, C.
    Pascoli, S.
    Meloni, D.
    Tang, J.
    Winter, W.
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical Particle Physics.
    Zhang, He
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Scotto-Lavina, L.
    Terranova, F.
    Bonesini, M.
    Tortora, L.
    Alekou, A.
    Aslaninejad, M.
    Bontoiu, C.
    Kurup, A.
    Jenner, L. J.
    Long, K.
    Pasternak, J.
    Pozimski, J.
    Back, J. J.
    Harrison, P.
    Beard, K.
    Bogacz, A.
    Berg, J. S.
    Stratakis, D.
    Witte, H.
    Snopok, P.
    Bliss, N.
    Cordwell, M.
    Moss, A.
    Pattalwar, S.
    Apollonio, M.
    High intensity neutrino oscillation facilities in Europe2013In: Physical Review Special Topics - Accelerators and Beams, E-ISSN 1098-4402, Vol. 16, no 2, p. 021002-Article in journal (Refereed)
    Abstract [en]

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Frejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of mu(+) and mu(-) beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He-6 and Ne-18, also stored in a ring. The far detector is also the MEMPHYS detector in the Frejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

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  • 49. Freund, Martin
    et al.
    Ohlsson, Tommy
    KTH, Superseded Departments (pre-2005), Physics.
    Matter enhanced neutrino oscillations with a realistic earth density profile2000In: Modern Physics Letters A, ISSN 0217-7323, E-ISSN 1793-6632, Vol. 15, no 13, p. 867-874Article in journal (Refereed)
    Abstract [en]

    We have investigated matter enhanced neutrino oscillations with a mantle-core-mantle step function and a realistic Earth matter density profile in both a two- and a three-neutrino scenario. We found that the realistic Earth matter density profile can be well approximated with the mantle-core-mantle step function and that there could be an influence on the oscillation channel nu(mu) --> nu(tau) due to resonant enhancement of one of the mixing angles.

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  • 50.
    Ghosh, Manojit
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden..
    Ohlsson, Tommy
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Center, Roslagstullsbacken 21, SE–106 91 Stockholm, Sweden.
    A comparative study between ESSnuSB and T2HK in determining the leptonic CP phase2020In: Modern Physics Letters A, ISSN 0217-7323, E-ISSN 1793-6632, Vol. 35, no 5, article id 2050058Article in journal (Refereed)
    Abstract [en]

    In this paper, we perform a comparative analysis between the future proposed longbaseline experiments ESSnuSB and T2HK in measuring the leptonic CP phase delta(CP). In particular, we study the effect of the neutrino mass ordering degeneracy and the leptonic mixing angle theta(23) octant degeneracy in the measurement of leptonic CP violation and precision for both experiments. Since the ESSnuSB (T2HK) experiment probes the second (first) oscillation maximum to study neutrino oscillations, the effect of these degeneracies are significantly different in both experiments. Our main conclusion is that for the ESSnuSB experiment, the information on the neutrino mass ordering does not play a major role in the determination of delta(CP), which is not the case for the T2HK experiment. However, the information on the true octant compromises the CP sensitivity of the ESSnuSB experiment as compared to T2HK if theta(23) lies in the lower octant. These conclusions are true for both the 540 km and 360 km baseline options for the ESSnuSB experiment. In addition, we investigate the effect of different running times in neutrino and antineutrino modes and the effect of theta(23) precision in measuring delta(CP).

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