Precision Measurement Of The Higgs Boson Mass And Search For Dilepton Mass Resonances In H To 4l Decays Using The Cms Detector At The Lhc
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Precision Measurement Of The Higgs Boson Mass And Search For Dilepton Mass Resonances In H To 4l Decays Using The Cms Detector At The Lhc
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Author : Jake Rosenzweig
language : en
Publisher:
Release Date : 2022
Precision Measurement Of The Higgs Boson Mass And Search For Dilepton Mass Resonances In H To 4l Decays Using The Cms Detector At The Lhc written by Jake Rosenzweig and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
Expectations of the total uncertainty are placed on the Higgs boson mass (mH) in the H to ZZstar to 4l (l = e, mu) decay channel. The value of mH, including statistical and systematic uncertainties, is estimated to be mH = 125.38 +- 0.11 [0.11 (stat.) +- 0.02 (syst.)] GeV. Once the data are unblinded, this measurement is predicted to be the world's most precise measurement of mH to date. The data used in the analysis were produced by proton-proton collisions at the Large Hadron Collider (LHC) with a center-of-mass energy of 13 TeV during Run 2 (2016-2018), corresponding to an integrated luminosity of 137.1 fb-1, and were collected by the Compact Muon Solenoid experiment. Using data sets from the same LHC run period, a search for low-mass dilepton resonances in Higgs boson decays to the 4l final state is also conducted. The Hidden Abelian Higgs Model is used in the search for a beyond the Standard Model dark photon (ZD) particle. Constraints are placed at 95% confidence level on the Higgs-mixing parameter k
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.
Observation And Measurement Of A Standard Model Higgs Boson Like Diphoton Resonance With The Cms Detector
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Author : Mingming Yang (Ph. D.)
language : en
Publisher:
Release Date : 2015
Observation And Measurement Of A Standard Model Higgs Boson Like Diphoton Resonance With The Cms Detector written by Mingming Yang (Ph. D.) 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.
This thesis concerns the observation of a new particle and the measurements of its properties, from the search of the Higgs boson through its decay into two photons at the CMS experiment at CERN's Large Hadron Collider (LHC), on the full LHC "Run I" data collected by the CMS detector during 2011 and 2012, consisting of proton-proton collision events at [square root of] s = 7 TeV with L = 5.1 fb-1 and at [square root of] s = 8 TeV with L = 19.7 fb-1, with the final calibration. In particular, an excess of events above the background expectation is observed, with a local significance of 5.7 standard deviations at a mass of 124.7 GeV, which constitutes the observation of a new particle through the two photon decay channel. A further measurement provides the precise mass of this new particle as 124.72+0.35 -0.36 GeV = 124.72+0.31 -0.32(stat)+0.16 -0.16(syst) GeV. Its total production cross section times two photon decay branching ratio relative to that of the Standard Model Higgs boson is determined as 1.12+0.26 -0.23 = 1.12+0.21 -0.21(stat)+0.15 -0.09(syst), compatible with the Higgs boson expectation. Further extractions of its properties relative to the Higgs boson, including the production cross section times decay branching ratios for separate Higgs production processes, couplings to bosons and to fermions, and effective couplings to the photon and to the gluon, are all compatible with the expectations for the Standard Model Higgs boson.
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.
Measurement Of The Higgs Boson Properties And Search For New Resonances Using W W Decays With The Cms Detector
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Author : Lorenzo Viliani
language : en
Publisher:
Release Date : 2017
Measurement Of The Higgs Boson Properties And Search For New Resonances Using W W Decays With The Cms Detector written by Lorenzo Viliani 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.
Discovery Of The Higgs Boson Measurements Of Higgs Boson Properties And Search For High Mass Beyond The Standard Model Scalar Particle In The Diphoton Final State With The Atlas Detector At The Large Hadron Collider
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Author : Hongtao Yang
language : en
Publisher:
Release Date : 2016
Discovery Of The Higgs Boson Measurements Of Higgs Boson Properties And Search For High Mass Beyond The Standard Model Scalar Particle In The Diphoton Final State With The Atlas Detector At The Large Hadron Collider written by Hongtao Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
With 4.8~$\rm{fb}^{-1}$ of proton-proton collision data collected at $\sqrt{s}=7~\rm{TeV}$ in 2011, and 5.9~$\rm{fb}^{-1}$ collected at $\sqrt{s}=8~\rm{TeV}$ in 2012 by the ATLAS detector at the Large Hadron Collider, an excess of 4.5 standard deviations from the background-only hypothesis is observed near 126.5~GeV in the diphoton invariant mass spectra. Along with the excesses observed in the $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$ and $H \rightarrow WW^{(*)}\rightarrow \ell\nu\ell\nu$ channels, the observation of a Higgs-like particle is established at 6.0 standard deviations level. With more data accumulated during LHC Run~1, the measurements of Higgs boson couplings and mass in the $H\to\gamma\gamma$ channel are conducted by the ATLAS experiment based on 4.5~$\rm{fb}^{-1}$ of proton-proton collisions at $\sqrt{s}=7~\rm{TeV}$ collected in 2011, and 20.3~$\rm{fb}^{-1}$ at $\sqrt{s}=8~\rm{TeV}$ collected in 2012. The combined signal strength, defined as number of observed Higgs boson decays to diphoton divided by the corresponding Standard Model prediction, is measured to be $1.17 \ ^{+0.28}_{-0.26}$ assuming the Higgs boson mass being 125.4~$\rm{GeV}$. The signal strengths for individual Higgs boson production processes are also measured, and are found to be in good consistency with the Standard Model. The mass of the Higgs boson is measured in $H\to\gamma\gamma$ channel by the ATLAS experiment to be $125.98 \pm 0.50$~\GeV. This measurement is combined with the ones from ATLAS $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$ as well as CMS $H\to\gamma\gamma$ and $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$. The Higgs boson mass measured from the combination is $125.09\pm0.24~\rm{GeV}$. With LHC center-of-mass energy increased to 13~TeV, a search for high mass Beyond the Standard Model scalar resonance is performed in the diphoton decay channel based on 15.4~$\rm{fb}^{-1}$ of proton-proton collision data collected by the ATLAS detector during 2015 and 2016. While a notable wide excess was first observed in the diphoton invariant mass spectrum from the 2015 data (3.2~$\rm{fb}^{-1}$) with mass near 750~GeV, it is not confirmed by the 2016 data with much higher statistics (12.4~$\rm{fb}^{-1}$). Limits on the production cross section times branching ratio of such resonances are set.
The Standard Model Higgs Boson Discovery Potential In The Decay Channel H Zz Superscript 4 Mu With The Cms Detector
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Author : Alexey Alexandrovich Drozdetskiy
language : en
Publisher:
Release Date : 2007
The Standard Model Higgs Boson Discovery Potential In The Decay Channel H Zz Superscript 4 Mu With The Cms Detector written by Alexey Alexandrovich Drozdetskiy and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
ABSTRACT: The Compact Muon Solenoid (CMS) is a general purpose detector at the Large Hadron Collider (LHC) currently under construction at CERN with start-up date in 2008. The putative Higgs boson is the most plausible solution for the mystery of mass in the Standard Model of elementary particles and its discovery is one of the prime goals for the LHC. Higgs boson search. Our research presents an optimized strategy for a Higgs boson search in its four-muon decay channel, H--> ZZ[superscript*]--> 4[mu], also known as a golden decay channel. The method automatically ensures an optimal signal-to-background ratio for any mass, at which the Higgs boson might appear. The most important theoretical and instrumental systematic errors are taken into account and our search was conducted in a broad range of possible Higgs boson masses. Muon reconstruction. We developed an algorithm for a fast and efficient muon track segment reconstruction in Cathode Strip Chambers. Designed to be CPU-efficient, the algorithm is specifically targeted for High Level Trigger purposes. The segment-finding efficiency and the spatial resolution attainable with the proposed algorithm and the required CPU time were validated using the cosmic ray data taken by the CMS in 2006. The results of validation showed the efficiency and spatial resolution attainable with the algorithm are well within the High Level Trigger requirements and the algorithm's timing performance is by far superior to all algorithms previously used in CMS.
Observation Of A Higgs Boson And Measurement Of Its Mass In The Diphoton Decay Channel With The Atlas Detector At The Lhc
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Author : Narei Lorenzo Martinez
language : en
Publisher:
Release Date : 2013
Observation Of A Higgs Boson And Measurement Of Its Mass In The Diphoton Decay Channel With The Atlas Detector At The Lhc written by Narei Lorenzo Martinez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
The Standard Model of the particle physics predicts the existence of a massive scalar boson, usually referred to as Higgs boson in the literature, as resulting from the Spontaneous Symmetry Breaking mechanism, needed to generate the mass of the particles. The Higgs boson whose mass is theoretically undetermined, is experimentally looked for since half a century by various experiments. This is the case of the ATLAS experiment at LHC which started taking data from high energy collisions in 2010. One of the most important decay channel in the LHC environment is the diphoton channel, because the final state can be completely reconstructed with high precision. The photon energy response is a key point in this analysis, as the signal would appear as a narrow resonance over a large background. In this thesis, a detailed study of the photon energy response, using the ATLAS electromagnetic calorimeter has been performed. This study has provided a better understanding of the photon energy resolution and scale, thus enabling an improvement of the sensitivity of the diphoton analysis as well as a precise determination of the systematic uncertainties on the peak position. The diphoton decay channel had a prominent role in the discovery of a new particle compatible with the Standard Model Higgs boson by the ATLAS and CMS experiments, that occurred in July 2012. Using this channel as well as the better understanding of the photon energy response, a measurement of the mass of this particle is proposed in this thesis, with the data collected in 2011 and 2012 at a center-of-mass energy of 7 TeV and 8 TeV. A mass of 126.8 +/- 0.2 (stat) +\- 0.7 (syst) GeV/c2 is found. The calibration of the photon energy measurement with the calorimeter is the source of the largest systematic uncertainty on this measurement. Strategies to reduce this systematic error are discussed.
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.
Measurement Of W Bb And A Search For Mssm Higgs Bosons With The Cms Detector At The Lhc
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Author :
language : en
Publisher:
Release Date : 2014
Measurement Of W Bb And A Search For Mssm Higgs Bosons With The Cms Detector At The Lhc written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
This thesis describes a Standard Model (SM) cross section measurement of W+bb as well as a search for neutral Higgs bosons in the Minimal Supersymmetric Extension of the Standard Model (MSSM) decaying to tau pairs. The measurement of W+bb was performed using proton-proton collisions at sqrt(s) = 7 TeV in a data sample collected with the CMS experiment at the LHC corresponding to an integrated luminosity of 5.0 1/fb. The W+bb events are selected in the W to muon + neutrino decay mode by requiring a muon with transverse momentum pT>25 GeV and pseudorapidity absolute eta less than 2.1, and exactly two b-tagged jets with pT>25 GeV and absolute eta less than 2.4. The measured W+bb production cross section in the fiducial region, calculated at the level of final-state particles, is 0.53± 0.05(stat.) ± 0.09 (syst.) ± 0.06 (theory) ± 0.01 (lum.) pb, in agreement with the SM prediction. This measurement is a sensitive test of heavy quark production calculated with perturbative QCD. It also serves as an important benchmark in new physics searches which include a single isolated lepton and one or more b jets in the final state, as W+bb becomes an irreducible background. Also presented is a search for the CP-even MSSM Higgs bosons, H and h, and the CP-odd MSSM pseudoscalar, A, in their decays to tau pairs. This search is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012 at a center-of-mass energy of 7 TeV and 8 TeV respectively. The dataset corresponds to an integrated luminosity of 24.6 1/fb, with 4.9 1/fb at 7 TeV and 19.7 1/fb at 8 TeV. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes the case where the Higgs boson is produced in association with a b-quark jet. No excess is observed in the tau-pair invariant-mass spectrum.