WZ di-boson measurements with the ATLAS experiment at the LHC and performance of resistive Micromegas in view of HL-LHC applications
Description
During the past two years, the CERN Large Hadron Collider (LHC) has performed exceptionally. The data collected by ATLAS made possible the first Standard Model physics measurements and produced a number of important experimental results. In the first part of this document the measurement of the WZ production with the ATLAS detector is presented and the second part is devoted to the study of resistive Micromegas properties, in view of the installation in the ATLAS spectrometer forward regions for the first phase of High Luminosity LHC (HL-LHC). The measurement of the WZ production probes the electroweak sector of the Standard Model at high energies and allows for generic tests for New Physics beyond the Standard Model. Two datasets of LHC proton-proton collisions were analyzed, 4.8 fb-1 of integrated luminosity at center-of-mass energy of 7 TeV, and 13 fb-1 at 8 TeV, collected in 2011 and the first half of 2012 respectively. Fully leptonic decay events are selected with electrons, muons and missing transverse momentum in the final state. Different date-driven estimates of the background were developed in the context of this analysis. The fiducial and total cross section of WZ production are measured and limits on anomalous triple gauge boson couplings are set. The second part of the document is devoted to the upgrade of the ATLAS detector. The conditions at the High Luminosity LHC calls for detectors capable of operating in a flux of collisions and background particles approximately ten times larger compared to today's conditions. The efficiency, resolution and robustness of resistive Micromegas were studied, as part of the R and D project aimed at the construction of large-area spark-resistant muon chambers using the Micromegas technology. (author)
Abstract (French)
Cette these comporte deux parties: la premiere porte sur la mesure de la production des paires de deux bosons de jauge WZ en utilisant les donnees collectees par le detecteur ATLAS aupres du grand collisionneur de proton-proton (LHC) au CERN. La deuxieme partie de la these est dediee a l'etude des proprietes des Micromegas resistives en vue de leur installation dans la partie avant du spectrometre a muons du detecteur ATLAS, durant la premiere phase de haute luminosite du LHC (HL-LHC). La mesure de production des paires WZ permet de tester le secteur electrofaible du Modele Standard a haute energie et de rechercher de la nouvelle physique au-dela du Modele Standard. Toute deviation par rapport aux predictions du Modele Standard serait l'indication de nouvelle physique. L'etude presentee dans cette these est basee sur les donnees des collisions proton-proton a une energie de centre de masse de 7 et 8 TeV. Elles correspondent a une luminosite integree de 4.8 et 13 fb-1 enregistrees respectivement durant l'annee 2011 et durant le premier semestre de 2012. Les etats finals de paires WZ se desintegrant en electrons, muons et energie transverse manquante, sont selectionnes. Les bruits de fond ttbar et Z+jets sont estimes a partir des donnees avec des methodes developpees dans le cadre de cette these. La section efficace fiducielle et totale de production des paires WZ sont calculees et les limites sur les couplages a trois bosons de jauge WWZ en sont extraites. La deuxieme partie de cette these est dediee a l'amelioration du spectrometre a muons d'ATLAS en vue de son fonctionnement a haute luminosite aupres du HL-LHC. La tres haute luminosite atteinte a l'horizon 2018 impose de prevoir des modifications substantielles sur l'ensemble des sous-detecteurs constituant ATLAS. L'efficacite, la resolution et la robustesse de Micromegas resistives sont etudiees dans le cadre d'un projet de R et D visant a la construction de chambres a muons vers l'avant a l'aide de la technologie Micromegas resistives
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Additional details
Additional titles
- Original title (French)
- Mesure des dibosons WZ avec le detecteur Atlas aupres du LHC et etude des performances des micromegas resistif en vue de leur application aupres du HL-LHC
Identifiers
Publishing Information
- Imprint Pagination
- 205 p.
- Report number
- FRCEA-TH--6621
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 47013486
- Subject category
- S72: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- BOSONS; CERN LHC; PARTICLE DECAY; STANDARD MODEL; TOTAL CROSS SECTIONS
- Descriptors DEC
- ACCELERATORS; CROSS SECTIONS; CYCLIC ACCELERATORS; DECAY; FIELD THEORIES; GRAND UNIFIED THEORY; MATHEMATICAL MODELS; PARTICLE MODELS; QUANTUM FIELD THEORY; STORAGE RINGS; SYNCHROTRONS; UNIFIED GAUGE MODELS
Optional Information
- Notes
- 113 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/inis/Contacts/; Also available from Service Commun de la Documentation de l'UPMC, 4 place Jussieu Boite courrier 192, 75252 PARIS CEDEX 05 (France)