Multiparticle Dynamics - Proceedings Of The Xxxii International Symposium

Multiparticle Dynamics - Proceedings Of The Xxxii International Symposium
Title Multiparticle Dynamics - Proceedings Of The Xxxii International Symposium PDF eBook
Author Alexey N Sissakian
Publisher World Scientific
Pages 469
Release 2003-07-14
Genre Science
ISBN 9814485721

Download Multiparticle Dynamics - Proceedings Of The Xxxii International Symposium Book in PDF, Epub and Kindle

This book covers a wide range of problems in elementary particle production physics — particle fluctuations and correlations, diffractive processes, soft and hard processes in quantum chromodynamics, heavy ion collisions, etc. Of the utmost importance are inclusion-theoretical papers devoted to the problems associated with high and even very high multiplicity particle production, making proposals for experiments at existing and forthcoming colliders of elementary particles.

Report of Research Activities

Report of Research Activities
Title Report of Research Activities PDF eBook
Author Yale University. Cowles Foundation for Research in Economics
Publisher
Pages 80
Release 1959
Genre Economics
ISBN

Download Report of Research Activities Book in PDF, Epub and Kindle

Scalar Boson Decays to Tau Leptons

Scalar Boson Decays to Tau Leptons
Title Scalar Boson Decays to Tau Leptons PDF eBook
Author Cécile Caillol
Publisher Springer
Pages 282
Release 2017-11-15
Genre Science
ISBN 3319706500

Download Scalar Boson Decays to Tau Leptons Book in PDF, Epub and Kindle

This thesis presents a study of the scalar sector in the standard model (SM), as well as various searches for an extended scalar sector in theories beyond the SM (BSM). The first part of the thesis details the search for an SM Higgs boson decaying to taus, and produced by gluon fusion, vector boson fusion, or associated production with a vector boson, leading to evidence for decays of the Higgs boson to taus. In turn, the second part highlights several searches for an extended scalar sector, with scalar boson decays to taus. In all of the analyses presented, at least one scalar boson decays to a pair of taus. The results draw on data collected by the Compact Muon Solenoid (CMS) detector during proton–proton collisions with a center-of-mass energy of 7 or 8 TeV.

Heavy Neutral Particle Decays to Tau Pairs

Heavy Neutral Particle Decays to Tau Pairs
Title Heavy Neutral Particle Decays to Tau Pairs PDF eBook
Author Michail Bachtis
Publisher Springer Science & Business Media
Pages 161
Release 2013-12-13
Genre Science
ISBN 3319032577

Download Heavy Neutral Particle Decays to Tau Pairs Book in PDF, Epub and Kindle

The work presented in this thesis spans a wide range of experimental particle physics subjects, starting from level-1 trigger electronics to the final results of the search for Higgs boson decay and to tau lepton pairs. The thesis describes an innovative reconstruction algorithm for tau decays and details how it was instrumental in providing a measurement of Z decay to tau lepton pairs. The reliability of the analysis is fully established by this measurement before the Higgs boson decay to tau lepton pairs is considered. The work described here continues to serve as a model for analysing CMS Higgs to tau leptons measurements.

Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC

Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC
Title Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC PDF eBook
Author Cristina Martin Perez
Publisher Springer Nature
Pages 291
Release 2022-02-09
Genre Science
ISBN 3030902064

Download Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC Book in PDF, Epub and Kindle

In this work, the interaction between the Higgs boson and the top quark is studied with the proton-proton collisions at 13 TeV provided by the LHC at the CMS detector at CERN (Geneva). At the LHC, these particles are produced simultaneously via the associate production of the Higgs boson with one top quark (tH process) or two top quarks (ttH process). Compared to many other possible outcomes of the proton-proton interactions, these processes are very rare, as the top quark and the Higgs boson are the heaviest elementary particles known. Hence, identifying them constitutes a significant experimental challenge. A high particle selection efficiency in the CMS detector is therefore crucial. At the core of this selection stands the Level-1 (L1) trigger system, a system that filters collision events to retain only those with potential interest for physics analysis. The selection of hadronically decaying τ leptons, expected from the Higgs boson decays, is especially demanding due to the large background arising from the QCD interactions. The first part of this thesis presents the optimization of the L1 τ algorithm in Run 2 (2016-2018) and Run 3 (2022-2024) of the LHC. It includes the development of a novel trigger concept for the High-Luminosity LHC, foreseen to start in 2027 and to deliver 5 times the current instantaneous luminosity. To this end, sophisticated algorithms based on machine learning approaches are used, facilitated by the increasingly modern technology and powerful computation of the trigger system. The second part of the work presents the search of the tH and ttH processes with the subsequent decays of the Higgs boson to pairs of τ lepton, W bosons or Z bosons, making use of the data recorded during Run 2. The presence of multiple particles in the final state, along with the low cross section of the processes, makes the search an ideal use case for multivariant discriminants that enhance the selectivity of the signals and reject the overwhelming background contributions. The discriminants presented are built using state-of-the-art machine learning techniques, able to capture the correlations amongst the processes involved, as well as the so-called Matrix Element Method (MEM), which combines the theoretical description of the processes with the detector resolution effects. The level of sophistication of the methods used, along with the unprecedented amount of collision data analyzed, result in the most stringent measurements of the tH and ttH cross sections up to date.

Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS

Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS
Title Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS PDF eBook
Author Francesco Pandolfi
Publisher Springer Science & Business Media
Pages 137
Release 2013-08-15
Genre Science
ISBN 3319009036

Download Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS Book in PDF, Epub and Kindle

The theoretical foundations of the Standard Model of elementary particles relies on the existence of the Higgs boson, a particle which has been revealed for the first time by the experiments run at the Large Hadron Collider (LHC) in 2012. As the Higgs boson is an unstable particle, its search strategies were based on its decay products. In this thesis, Francesco Pandolfi conducted a search for the Higgs boson in the H → ZZ → l + l - qq Decay Channel with 4.6 fb -1 of 7 TeV proton-proton collision data collected by the Compact Muon Solenoid (CMS) experiment. The presence of jets in the final state poses a series of challenges to the experimenter: both from a technical point of view, as jets are complex objects and necessitate of ad-hoc reconstruction techniques, and from an analytical one, as backgrounds with jets are copious at hadron colliders, therefore analyses must obtain high degrees of background rejection in order to achieve competitive sensitivity. This is accomplished by following two directives: the use of an angular likelihood discriminant, capable of discriminating events likely to originate from the decay of a scalar boson from non-resonant backgrounds, and by using jet parton flavor tagging, selecting jets compatible with quark hadronization and discarding jets more likely to be initiated by gluons. The events passing the selection requirements in 4.6 fb -1 of data collected by the CMS detector are examined, in the search of a possible signal compatible with the decay of a heavy Higgs boson. The thesis describes the statistical tools and the results of this analysis. This work is a paradigm for studies of the Higgs boson with final states with jets. The non-expert physicists will enjoy a complete and eminently readable description of a proton-proton collider analysis. At the same time, the expert reader will learn the details of the searches done with jets at CMS.

The Search and Discovery of the Higgs Boson

The Search and Discovery of the Higgs Boson
Title The Search and Discovery of the Higgs Boson PDF eBook
Author Luis Roberto Flores Castillo
Publisher Morgan & Claypool Publishers
Pages 76
Release 2016-01-01
Genre Science
ISBN 1681740788

Download The Search and Discovery of the Higgs Boson Book in PDF, Epub and Kindle

This book provides a general description of the search for and discovery of the Higgs boson (particle) at CERN’s Large Hadron Collider. The goal is to provide a relatively brief overview of the issues, instruments and techniques relevant for this search; written by a physicist who was directly involved. The Higgs boson mat be the one particle that was studied the most before its discovery and the story from postulation in 1964 to detection in 2012 is a fascinating one. The story is told here while detailing the fundamentals of particle physics.