Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Searches for a Charged Higgs Boson in ATLAS and Development of Novel Technology for Future Particle Detector Systems
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The discovery of a charged Higgs boson (H±) would be a clear indication for physics beyond the Standard Model. This thesis describes searches for charged Higgs bosons with the ATLAS experiment at CERN’s Large Hadron Collider (LHC). The first data collected during the LHC Run 1 is analysed, searching for a light charged Higgs boson (mH±<mtop), which decays predominantly into a tau-lepton and a neutrino. Different final states with one or two leptons (electrons or muons), as well as leptonically or hadronically decaying taus, are studied, and exclusion limits are set.

The background arising from misidentified non-prompt electrons and muons was estimated from data. This so-called "Matrix Method'' exploits the difference in the lepton identification between real, prompt, and misidentified or non-prompt electrons and muons. The Matrix Method is used in all charged Higgs boson searches in this thesis.

In 2024 the LHC will be upgraded into a High Luminosity LHC (HL-LHC). The ATLAS detector is expected to collect around 300 fb-1 of collision data until 2022, whereas the HL-LHC will deliver about 250-300 fb-1 of data per year. This will increase the mean number of interactions per bunch crossing, resulting in larger particle fluxes. This puts challenging requirements on the electronics. In order to keep trigger and data rates at manageable levels, new trigger concepts require more intelligence at early stage which possibly results in more cables and connectors, inside the detector which lead to degraded performance of the detector system.

This thesis presents new concepts using wireless technology at 60 GHz, in order add more data links inside the detector system without adding much material. Patch antennas have been developed, operating at 60 GHz. Manufacture methods have been investigated, and the fabrication tolerances and bandwidth of these antennas have been studied. Also, concepts of using passive repeaters have been investigated, to make the 60 GHz signal pass boundaries. These repeaters can be used to connect intelligence inside the detector, but also for reading out data from the whole detector radially.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. , 119 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1222
Keyword [en]
Charged Higgs boson, Matrix Method, ATLAS, 60 GHz, future particle detector
National Category
Subatomic Physics
Research subject
Physics with specialization in Elementary Particle Physics
Identifiers
URN: urn:nbn:se:uu:diva-242491ISBN: 978-91-554-9153-6 (print)OAI: oai:DiVA.org:uu-242491DiVA: diva2:784537
Public defence
2015-03-20, Polhemssalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2015-02-23 Created: 2015-01-26 Last updated: 2015-03-11Bibliographically approved
List of papers
1. Search for charged Higgs bosons decaying via H-+/- -> tau nu in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS detector
Open this publication in new window or tab >>Search for charged Higgs bosons decaying via H-+/- -> tau nu in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS detector
Show others...
2012 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, 039- p.Article in journal (Refereed) Published
Abstract [en]

The results of a search for charged Higgs bosons are presented. The analysis is based on 4.6 fb(-1) of proton-proton collision data at root s = 7TeV collected by the ATLAS experiment at the Large Hadron Collider, using top quark pair events with a tau lepton in the final state. The data are consistent with the expected background from Standard Model processes. Assuming that the branching ratio of the charged Higgs boson to a tau lepton and a neutrino is 100%, this leads to upper limits on the branching ratio of top quark decays to a b quark and a charged Higgs boson between 5% and 1% for charged Higgs boson masses ranging from 90GeV to 160GeV, respectively. In the context of the m(h)(max) scenario of the MSSM, tan beta above 12-26, as well as between 1 and 2-6, can be excluded for charged Higgs boson masses between 90GeV and 150GeV.

Keyword
Hadron-Hadron Scattering
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-182660 (URN)10.1007/JHEP06(2012)039 (DOI)000306416500040 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1007/JHEP06(2012)039

Available from: 2012-10-15 Created: 2012-10-15 Last updated: 2017-12-07Bibliographically approved
2. Search for charged Higgs bosons through the violation of lepton universality in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS experiment
Open this publication in new window or tab >>Search for charged Higgs bosons through the violation of lepton universality in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS experiment
Show others...
2013 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 3, 076- p.Article in journal (Refereed) Published
Abstract [en]

In several extensions of the Standard Model, the top quark can decay into a bottom quark and a light charged Higgs boson H+, t -> bH(+), in addition to the Standard Model decay t -> bW. Since W bosons decay to the three lepton generations equally, while H+ may predominantly decay into tau nu, charged Higgs bosons can be searched for using the violation of lepton universality in top quark decays. The analysis in this paper is based on 4.6 fb(-1) of proton-proton collision data at root s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider. Signatures containing leptons (e or mu) and/or a hadronically decaying tau (tau(had)) are used. Event yield ratios between e+ tau(had) and e + mu, as well as between mu + tau(had) and mu + e, final states are measured in the data and compared to predictions from simulations. This ratio-based method reduces the impact of systematic uncertainties in the analysis. No significant deviation from the Standard Model predictions is observed. With the assumption that the branching fraction B(H+ -> tau nu) is 100%, upper limits in the range 3.2%-4.4% can be placed on the branching fraction B(t -> bH(+)) for charged Higgs boson masses m(H+) in the range 90-140GeV. After combination with results from a search for charged Higgs bosons in t (t) over bar decays using the tau(had) + jets final state, upper limits on B(t -> bH(+)) can be set in the range 0.8%-3.4%, for m(H+) in the range 90-160GeV.

Keyword
Hadron-Hadron Scattering
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-200414 (URN)10.1007/JHEP03(2013)076 (DOI)000317521200076 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1007/JHEP03(2013)076

Available from: 2013-05-27 Created: 2013-05-27 Last updated: 2017-12-06Bibliographically approved
3. Estimation of non-prompt and fake lepton backgrounds in final states with top quarks produced in proton-proton collisions at \sqrts=8 TeV with the ATLAS detector
Open this publication in new window or tab >>Estimation of non-prompt and fake lepton backgrounds in final states with top quarks produced in proton-proton collisions at \sqrts=8 TeV with the ATLAS detector
2014 (English)Report (Other academic)
Place, publisher, year, edition, pages
Geneva: CERN, 2014
Keyword
ATLAS, Fake Lepton, Matrix Method
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-242495 (URN)
Note

Published by "The ATLAS Collaboration"

Available from: 2015-01-26 Created: 2015-01-26 Last updated: 2015-03-11
4. Wireless data transfer with mm-waves for future tracking detectors
Open this publication in new window or tab >>Wireless data transfer with mm-waves for future tracking detectors
Show others...
2014 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, C11008- p.Article in journal (Refereed) Published
Abstract [en]

Wireless data transfer has revolutionized the consumer market for the last decade generating many products equipped with transmitters and receivers for wireless data transfer. Wireless technology opens attractive possibilities for data transfer in future tracking detectors. The reduction of wires and connectors for data links is certainly beneficial both for the material budget and the reliability of the system. An advantage of wireless data transfer is the freedom of routing signals which today is particularly complicated when bringing the data the first 50 cm out of the tracker. With wireless links intelligence can be built into a tracker by introducing communication between tracking layers within a region of interest which would allow the construction of track primitives in real time. The wireless technology used in consumer products is however not suitable for tracker readouts. The low data transfer capacity of current 5 GHz transceivers and the relatively large feature sizes of the components is a disadvantage. Due to the requirement of high data rates in tracking detectors high bandwidth is required. The frequency band around 60 GHz turns out to be a very promising candidate for data transfer in a detector system. The high baseband frequency allows for data transfer in the order of several Gbit/s. Due to the small wavelength in the mm range only small structures are needed for the transmitting and receiving electronics. The 60 GHz frequency band is a strong candidate for future WLAN applications hence components are already starting to be available on the market. Patch antennas produced on flexible Printed Circuit Board substrate that can be used for wireless communication in future trackers are presented in this article. The antennas can be connected to transceivers for data transmission/reception or be connected by wave-guides to structures capable of bringing the 60 GHz signal behind boundaries. Results on simulation and fabrication of these antennas are presented as well as studies on the sensitivity of production tolerances.

Keyword
Particle tracking detectors, Front-end electronics for detector readout, Data acquisition concepts, Manufacturing
National Category
Accelerator Physics and Instrumentation Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-240001 (URN)10.1088/1748-0221/9/11/C11008 (DOI)000345026000008 ()
Available from: 2015-01-05 Created: 2015-01-05 Last updated: 2017-12-05Bibliographically approved
5. Radial transfer of tracking data with wireless links
Open this publication in new window or tab >>Radial transfer of tracking data with wireless links
Show others...
2014 (English)Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Proceedings of Science, 2014
National Category
Subatomic Physics Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-242499 (URN)
Conference
Technology and Instrumentation in Particle Physics 2014 (TIPP2014)
Available from: 2015-01-26 Created: 2015-01-26 Last updated: 2016-05-03

Open Access in DiVA

fulltext(2946 kB)265 downloads
File information
File name FULLTEXT01.pdfFile size 2946 kBChecksum SHA-512
fae56d1f927bba04fa9a38cd187a28913d8116088d33dc0acadd099a012bb7fc97dc836cca0f4cd7a5c2a3f216aec25c4ba59baab8457100517a1fe59554eca0
Type fulltextMimetype application/pdf