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A Highly Granular Silicon-Tungsten Electromagnetic Calorimeter and Top Quark Production at the International Linear Collider AIDA-THESIS-2014-002 AIDA Advanced European Infrastructures for Detectors at Accelerators Academic Dissertation A Highly Granular Silicon-Tungsten Electromagnetic Calorimeter and Top Quark Production at the International Linear Collider Rouen¨ e,´ J (CNRS) 30 June 2014 The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project AIDA, grant agreement no. 262025. This work is part of AIDA Work Package 9: Advanced infrastructures for detector R&D. The electronic version of this AIDA Publication is available via the AIDA web site <http://cern.ch/aida> or on the CERN Document Server at the following URL: <http://cds.cern.ch/search?p=AIDA-THESIS-2014-002> AIDA-THESIS-2014-002 A Highly Granular Silicon-Tungsten Electromagnetic Calorimeter and Top Quark Production at the International Linear Collider J´er´emy Rou¨en´e To cite this version: J´er´emy Rou¨en´e. A Highly Granular Silicon-Tungsten Electromagnetic Calorimeter and Top Quark Production at the International Linear Collider. High Energy Physics - Experiment. Universit´eParis Sud - Paris XI, 2014. English. <NNT : 2014PA112126>. <tel-01062136> HAL Id: tel-01062136 https://tel.archives-ouvertes.fr/tel-01062136 Submitted on 9 Sep 2014 HAL is a multi-disciplinary open access L'archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destin´eeau d´ep^otet `ala diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publi´esou non, lished or not. The documents may come from ´emanant des ´etablissements d'enseignement et de teaching and research institutions in France or recherche fran¸caisou ´etrangers,des laboratoires abroad, or from public or private research centers. publics ou priv´es. LAL 14-154 UNIVERSITE´ PARIS-SUD XI Ecole´ Doctorale : ED517 - “Particules, Noyaux et Cosmos” Laboratoire de l’Acc´el´erateur Lin´eaire LAL, Univ. Paris-Sud, CNRS/IN2P3, Orsay, FRANCE DISCIPLINE : PHYSIQUE DES PARTICULES THESE` DE DOCTORAT Soutenue le 30 Juin 2014 par J´er´emy ROUEN¨ E´ Calorim`etre ´electromagn´etique silicium-tungst`ene hautement granulaire Production du quark top `al’International Linear Collider Composition du Jury : Prof. Achille STOCCHI Pr´esident du jury Prof. Hitoshi YAMAMOTO Rapporteur Prof. Werner BERNREUTHER Rapporteur Dr. Matthew WING Examinateur Dr. Maxim TITOV Examinateur Dr. Roman POSCHL¨ Directeur de th`ese Dr. Fran¸cois RICHARD Membre invit´e Th`ese pr´epar´ee au Laboratoire de l’Acc´el´erateur Lin´eaire - UMR8607 Centre Scientifique d’Orsay, Bˆat. 200, BP 34 91898 Orsay CEDEX R´esum´e Cette th`ese porte sur deux aspects de l’International Linear Collider (ILC) qui est un projet d’un collisionneur lin´eaire ´electron-positron avec une ´energie dans le centre de masse pouvant aller jusqu’`a500 GeV. Le premier aspect est l’´elaboration d’un calorim`etre ´electromagn´etique silicium- tungst`ene (SiW-ECAL) pour l’un des d´etecteurs de l’ILC. Le concept de ce d´e- tecteur est pilot´epar les sp´ecifications du faisceau de l’ILC et par l’algorithme du Particle Flow (PFA). Cela n´ecessite un calorim`etre hautement granulaire et tr`es compact avec l’´electronique directement int´egr´ee `al’int´erieur. Pour prouver les capacit´es du SiW-ECAL, un prototype technologique a ´et´e construit et test´e en faisceau de test `aDESY. Les r´esultats sont pr´esent´es ici et montrent, apr`es la proc´edure de calibration, un signal sur bruit de 10, mˆeme en mode power pulsing. Le deuxi`eme aspect est l’´etude de l’un des canaux physique importants de l’ILC, la production de pairs de quark top anti-top. L’objectif principal de cette ´etude est de d´eterminer la pr´ecision que nous pouvons attendre `al’ILC sur le couplage du top avec le boson W et le photon. Pour obtenir cette pr´ecision diff´e- rentes observables sont utilis´ees, la section efficace, l’asym´etrie avant - arri`ere et la distribution d’h´elicit´ede la production de pairs de quark top anti-top. L’analyse est bas´ee sur les ´ev´enements avec des faisceaux polaris´es et reconstruit avec la simulation compl`ete du d´etecteur ILD, qui est le d´etecteur du SiW-ECAL, pour le Detector Baseline Design de l’ILD. Au final l’erreur attendue sur le couplage du quark top est de l’ordre de 2 %. Mots-clefs : Calorim`etre, physique des particules, quark top, ILC, CALICE. Abstract A Highly Granular Silicon-Tungsten Electromagnetic Calorimeter Top Quark Production at the International Linear Collider This thesis deals with two aspects of the International Linear Collider (ILC) which is a project of a linear electron-positron collider of up to at least 500 GeV center of mass energy. The first aspect is the development of a silicon-tungsten electromagnetic calorime- ter (SiW-ECAL) for one of the detectors of the ILC. The concept of this detector is driven by the ILC beam specifications and by the Particle Flow Algorithm (PFA). This requires highly granular calorimeter and very compact one with integrated electronics. To prove the capability of the SiW- ECAL a technological prototype has been built and tested in test beam at DESY. The results are presented here, and show, after the calibration procedure a signal over noise ratio of 10, even in the power pulsing mode. The second aspect is the study of one of the important physics channels of the ILC, the top anti-top quark pairs production. The main goal of this study is to determine the precision that we can expect at the ILC on the top coupling with the W boson and the photon. To get this precision differents observables are used, the cross- section, the forward- backward asymmetry and the helicity distri- bution of the top anti-top quark pairs production. The analysis is based on the events with polarized beams and reconstructed with the full simulation of the ILD detector, which is the detector of the SIW- ECAL, for the Detector Baseline De- sign of the ILD. The final expected errors on the top coupling is of the order of 2%. Keywords : Calorimeter, particles physics, top quark, ILC, CALICE. Remerciements Je voudrais remercier le directeur du Laboratoire de l’Acc´el´erateur Lin´eaire, Achille STOCCHI, ainsi que tout le personnel pour m’avoir permis d’effectuer ma th`ese dans d’excellentes conditions pendant ces trois ans. Je remercie ´egalement les membres de mon jury, Prof. Hitoshi YAMAMOTO, Prof. Werner BERNREUTHER, Dr. Matthew WING, et Dr. Maxim TITOV, de me faire l’honneur de leur pr´esence. Je veux bien ´evidemment remercier mon directeur de th`ese, Dr. Roman POSCHL,¨ pour m’avoir laiss´etravailler de mani`ere autonome, tout en ´etant toujours pr´esent quand j’avais besoin de lui. Je remercie ´egalement mes coll`egues, Fran¸cois, Philippe, Thibault, Amjad, Naomi et tous les autres pour leur aide et leurs conseils. Je tiens aussi `aremercier M. Benoˆıt de Pr´eville qui m’a donn´ele goˆut pour la physique en pr´epa et m’a encourag´e`apoursuivre dans cette voie. Finalement je remercie mes amis et ma famille, mes fr`eres Loris et Florian pour leur soutien, bien que, malgr´emes tentatives d’explication, ils doivent toujours se demander ce que j’ai bien pu faire pendant ces trois ann´ees de th`ese. Et enfin je remercie Anne-Ga¨elle pour son soutien et pour avoir support´emes nombreux d´eplacements `al’´etranger. Notre aventure Parisienne se termine avec ma th`ese, et nous allons pouvoir rentrer chez nous pour commencer une aventure encore plus excitante en tant que parents. `ames parents, Gis`eleet Alain 6 Contents I General Introduction 11 1 The Standard Model of Particles Physics 15 1.1 TheParticlesoftheStandardModel . 15 1.1.1 Thefermions .......................... 15 1.1.2 TheBosons ........................... 17 1.2 The Fundamental Forces in the Standard Model . 17 1.2.1 A simple example: the Electromagnetic interaction . ... 17 1.2.2 Electroweak interactions . 19 1.2.3 Stronginteraction. 20 1.3 Spontaneous Symmetry Breaking and the Higgs Boson . 21 1.3.1 Spontaneous symmetry breaking: the Higgs mechanism . 21 1.3.2 Giving a mass to the Fermions . 23 1.3.3 Discovery of the Higgs Boson . 24 1.4 TheTopQuark ............................. 25 1.4.1 Propertiesofthetopquark . 25 1.4.2 Electroweak couplings of the top quark . 26 1.5 OpenQuestionsinParticlePhysics . 27 2 The International Linear Collider 31 2.1 PresentationandMotivationoftheILC. 31 2.2 Physics at the International Linear Collider . .... 33 2.3 TheAccelerator............................. 34 2.3.1 TheElectronSource . 38 2.3.2 ThePositronSource . 38 2.3.3 TheDampingRings ...................... 38 2.3.4 TheMainLinac......................... 39 2.3.5 TheBeamDeliverySystem . 39 3 The International Large Detector 41 3.1 PresentationoftheILD . 41 3.2 The Particle Flow Algorithm . 44 7 CONTENTS 3.3 TheTrackingSystemoftheILD. 46 3.3.1 TheVertexDetector . 46 3.3.2 TheSiliconTracking . 47 3.3.3 TheTimeProjectionChamber . 47 3.4 TheCalorimeterSystemoftheILD . 48 3.4.1 The Electromagnetic Calorimeter . 48 3.4.2 TheHadronicCalorimeter . 49 3.5 TheOuterPartoftheILD. 49 II The Silicon-Tungsten Electromagnetic Calorimeter 51 4 The Physics Prototype of the SiW-ECAL 55 4.1 Presentation............................... 55 4.2 Design of the SiW-ECAL Physics Prototype . 55 4.3 CalibrationandResults . 57 4.3.1 The MIP Calibration Algorithm . 58 4.3.2 Response of the Physics Prototype to Electrons . 59 5 The Technological Prototype of the SiW-ECAL 63 5.1 Presentation............................... 63 5.2 GeneralDesign ............................. 63 5.2.1 TheMechanicalStructure . 63 5.2.2 TheActiveSensorsUnit . 64 5.3 TheSKIROC2ASIC .......................... 66 5.4 TheTestBeamSetup.......................... 70 5.5 TheTriggerCalibration . 71 5.5.1 TheTriggerThreshold .
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