Search For Higgs Boson Pair Production At The Cms Experiment Of The Lhc And Studies Of A New Trigger Algorithm For The Muon Chambers In Hl Lhc
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Search For Higgs Boson Pair Production At The Cms Experiment Of The Lhc And Studies Of A New Trigger Algorithm For The Muon Chambers In Hl Lhc
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Author : Jaime León Holgado
language : en
Publisher:
Release Date : 2023
Search For Higgs Boson Pair Production At The Cms Experiment Of The Lhc And Studies Of A New Trigger Algorithm For The Muon Chambers In Hl Lhc written by Jaime León Holgado and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
This thesis reports a search for double Higgs boson production at the Large Hadron Collider (LHC). This process is predicted by the Standard Model of particle physics (SM), with a production cross section around 1000 times smaller than single Higgs boson production. Its study can provide information about the Higgs potential, the Higgs self-coupling, and its couplings to other SM particles such as the t quark or the vector bosons. Additionally, Beyond the Standard Model (BSM) effects can manifest as modiffications on the production cross section or changes in event kinematics. Two production modes are studied, gluon fusion (ggF) and vector boson fusion (VBF). This search is performed using data from the Compact Muon Solenoid (CMS) experiment during the so-called Run 2 of the LHC, corresponding to proton-proton collision data collected in 2016, 2017, and 2018, and amounting to a total integrated luminosity of around 138 fb1. The analysis considers the final state where a Higgs boson decays into two b quarks and the other decays into two leptons. Since it has an intermediate branching ratio and relatively low background, it is considered as one of the golden channels in the search for double Higgs boson production ...
Search For Higgs Boson Pair Production In The Bb Decay Channel
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Author : Luca Cadamuro
language : en
Publisher: Springer
Release Date : 2018-12-06
Search For Higgs Boson Pair Production In The Bb Decay Channel written by Luca Cadamuro and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-12-06 with Science categories.
This thesis presents innovative contributions to the CMS experiment in the new trigger system for the restart of the LHC collisions in Run II, as well as original analysis methods and important results that led to official publications of the Collaboration. The author's novel reconstruction algorithms, deployed on the Field-Programmable Gate Arrays of the new CMS trigger architecture, have brought a gain of over a factor 2 in efficiency for the identification of tau leptons, with a very significant impact on important H boson measurements, such as its decays to tau lepton pairs and the search for H boson pair production. He also describes a novel analysis of HH → bb tautau, a high priority physics topic in a difficult channel. The original strategy, optimisation of event categories, and the control of the background have made the result one of the most sensitive concerning the self-coupling of the Higgs boson among all possible channels at the LHC.
Search For The Higgs Boson Produced In Association With Top Quarks With The Cms Detector At The Lhc
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Author : Cristina Martin Perez
language : en
Publisher: Springer
Release Date : 2022-03-14
Search For The Higgs Boson Produced In Association With Top Quarks With The Cms Detector At The Lhc written by Cristina Martin Perez and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-03-14 with Science categories.
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 Invisible Decays Of The Higgs Boson Produced Via Vector Boson Fusion At The Lhc With Cms Run 2 Data
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Author : Alp Akpinar
language : en
Publisher: Springer Nature
Release Date : 2024-12-23
Search For Invisible Decays Of The Higgs Boson Produced Via Vector Boson Fusion At The Lhc With Cms Run 2 Data written by Alp Akpinar and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-12-23 with Science categories.
This thesis reports the latest measurements on one of the leading dark matter searches conducted by the Compact Muon Solenoid (CMS) experiment at CERN, leading to some of the most stringent constraints on hypothesized interactions between the Higgs boson and dark matter. The thesis also includes further research about the future outlook of the experiment, including exploratory research on the adaptation of deep learning models in future dark matter analyses to improve analysis sensitivity, and the design of a new type of data processing hardware to be used in the next phase of the CMS experiment.
Observation Of A New State In The Search For The Higgs Boson At Cms
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Author : Giovanni Petrucciani
language : en
Publisher: Springer
Release Date : 2014-12-04
Observation Of A New State In The Search For The Higgs Boson At Cms written by Giovanni Petrucciani and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-12-04 with Science categories.
This book describes the searches that lead to the discovery of a Higgs boson performed at CMS, one of the two main experiments at the CERN LHC. After an overview of the theory and of the CMS experiment, all search channels are described, with emphasis on the ones with the best sensitivity. The statistical methodology used to analyse and the outcomes of the searches and the discovery results are then presented in detail.
Seaching For A Charged Higgs Boson And Development Of A Hardware Track Trigger With The Atlas Experiment
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Author : Joakim Gradin
language : en
Publisher:
Release Date : 2017
Seaching For A Charged Higgs Boson And Development Of A Hardware Track Trigger With The Atlas Experiment written by Joakim Gradin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
In 2012 the ATLAS and CMS experiments announced the discoveryof a new particle, a Higgs boson. This particle was hypothesized in the1960's and explains how fundamental particles get their mass. However, amodel with a single Higgs boson is still not able to explain the aforemen-tioned cosmological observations. An electrically charged Higgs boson isa feature of many suggested extensions of the current model, includingsupersymmetry. The properties of such a particle, e.g. its mass and howit interacts with other particles are not fixed by theory but forms a pa-rameter space in which we must look for it. Searches for charged Higgsbosons have been performed prior to the LHC, but with the new energyscale of the LHC, the experiments have been able to look for heavier par-ticles. In this work we searched for a charged Higgs boson decaying intothe heaviest two quarks, a top and bottom pair. No deviations from thestandard model were found in the data gathered up until 2016, and hencewe can set upper limits on the production rate of a charged Higgs boson.These limits can then be used to exclude parts of the parameter space.The LHC will be upgraded around 2025 to increase the luminosity,that is the intensity of the proton beams. Protons are not acceleratedone by one at the LHC but in bunches. The luminosity can be increasedby using more protons per bunch but also by squeezing the bunches to besmaller at the point of collision. This means that the rate at which we canhope to produce rare events will increase but also that the backgroundrates and so called pile-up, the number of proton collisions per bunchcrossing, will increase. The rate of bunch crossings at the LHC is muchtoo high for ATLAS to be able to readout and store all data for eachevent, instead we use triggers that select events which look interesting.The current triggers are not suited for the high rates and pile-up of theHigh Luminosity (HL) LHC after the upgrade and must thus be improved.A way to do this is to use the information from the tracking detector thatprovides information on the trajectories of charged particles. By usingalgorithms that can be implemented in hardware a track trigger can bemade fast enough to work within the short latency required at the HL-LHC. The tracking detector provides space points, measurements of theparticle trajectories at different intervals, to which a track can be fitted.The amount of data from the tracker is very large, and performing trackfits on all the combinations of the space point would take too much time.Therefore a track trigger must be able to select a subset of space points onwhich to perform the track fit. For this thesis we have explored the idea ofusing standalone electron and muon triggers to select a part of the trackervolume, and then select space points that match precomputed patternsthat correspond to high energy particles. It has been shown that this isa viable option to reduce background rates while keeping high efficiencyfor the events we want to keep, even in high pile-up conditions.
Response Of The High Granularity Calorimeter Hgcal And Characterisation Of The Higgs Boson
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Author : Matteo Bonanomi
language : en
Publisher: Springer
Release Date : 2023-05-23
Response Of The High Granularity Calorimeter Hgcal And Characterisation Of The Higgs Boson written by Matteo Bonanomi and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-05-23 with Science categories.
This book highlights the most complete characterization of the Higgs boson properties performed to date in the "golden channel," i.e., decay into a pair of Z bosons which subsequently decay into four leptons. The data collected by the CMS experiment in the so-called Run-II data-taking period of the LHC are used to produce an extensive set of results that test in detail the predictions of the Standard Model. Given the remarkable predictive power of the SM when including the Higgs boson, possible new physics will require even more extensive studies at higher statistics. A massive upgrade of the detectors is necessary to maintain the current physics performance in the harsh environment of the High-Luminosity LHC (HL-LHC) project, expected to start by the end of 2027. The CMS Collaboration will replace the current endcap calorimeters with a High Granularity Calorimeter (HGCAL). The HGCAL will be the very first large-scale silicon-based imaging calorimeter ever employed in ahigh-energy physics experiment. This book presents the results of the analysis of the test beam data collected with the first large-scale prototype of the HGCAL. The results of this analysis are used to corroborate the final design of the HGCAL and its nominal physics performance expected for the HL-LHC operations.
A Search For Pair Production Of New Light Bosons Decaying Into Muons
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Author :
language : en
Publisher:
Release Date : 2015
A Search For Pair Production Of New Light Bosons Decaying Into Muons written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
In this study, a search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7 fb-1 collected in proton-proton collisions at center-of-mass energy of √s = 8 TeV. No excess is observed in the data relative to standard model background expectation and a model independent upper limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context of the next-to-minimal supersymmetric standard model, and the second one in scenarios containing a hidden sector, including those predicting a nonnegligible light boson lifetime.
Discovery Of The Higgs Boson
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Author : Aleandro Nisati
language : en
Publisher: World Scientific
Release Date : 2016-08-26
Discovery Of The Higgs Boson written by Aleandro Nisati and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-08-26 with Science categories.
The recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics.
Search For The Higgs Boson Decaying Into Tau Lepton Pairs With The Matrix Element Method And Tau Trigger Optimization In The Cms Experiment At The Lhc
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Author : Luca Mastrolorenzo
language : en
Publisher:
Release Date : 2015
Search For The Higgs Boson Decaying Into Tau Lepton Pairs With The Matrix Element Method And Tau Trigger Optimization In The Cms Experiment At The Lhc written by Luca Mastrolorenzo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.