Download or read book Search for the MSSM Neutral Higgs Bosons with the CMS Experiment at LHC written by Gianni Masetti and published by . This book was released on 2005 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of W Bb and a Search for MSSM Higgs Bosons with the CMS Detector at the LHC written by and published by . This book was released on 2014 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for Neutral MSSM Higgs Bosons Decaying to mu mu in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for neutral Higgs bosons predicted in the minimal supersymmetric standard model (MSSM) for [mu]+[mu]- decay channels is presented. Our analysis uses data collected by the CMS experiment at the LHC in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.3 fb-1, respectively. The search is sensitive to Higgs bosons produced either through the gluon fusion process or in association with a bb quark pair. No statistically significant excess is observed in the [mu]+[mu]- mass spectrum. Results are interpreted in the framework of several benchmark scenarios, and the data are used to set an upper limit on the MSSM parameter tan [beta] as a function of the mass of the pseudoscalar A boson in the range from 115 to 300 GeV. Furthermore, the model independent upper limits are given for the product of the cross section and branching fraction for gluon fusion and b quark associated production at √s = 8 TeV. As a result, they are the most stringent limits obtained to date in this channel.

Download or read book Search for Neutral MSSM Higgs Bosons Decaying to mu mu in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for neutral Higgs bosons predicted in the minimal supersymmetric standard model (MSSM) for ?+?- decay channels is presented. Our analysis uses data collected by the CMS experiment at the LHC in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.3 fb-1, respectively. The search is sensitive to Higgs bosons produced either through the gluon fusion process or in association with a bb quark pair. No statistically significant excess is observed in the ?+?- mass spectrum. Results are interpreted in the framework of several benchmark scenarios, and the data are used to set an upper limit on the MSSM parameter tan ? as a function of the mass of the pseudoscalar A boson in the range from 115 to 300 GeV. Furthermore, the model independent upper limits are given for the product of the cross section and branching fraction for gluon fusion and b quark associated production at √s = 8 TeV. As a result, they are the most stringent limits obtained to date in this channel.

Download or read book Observation of a New State in the Search for the Higgs Boson at CMS written by Giovanni Petrucciani and published by Springer. This book was released on 2014-12-04 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for Neutral MSSM Higgs Bosons Decaying to a Pair of Tau Leptons in Pp Collisions written by and published by . This book was released on 2014 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 24.6 fb−1, with 4.9 fb−1 at 7 TeV and 19.7 fb−1 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-lepton-pair invariant mass spectrum. Exclusion limits are presented in the MSSM parameter space for different benchmark scenarios, mhmax, mhmod+, mhmod-, light-stop, light-stau, [tau]-phobic, and low-mH. Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given.

Download or read book Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC written by Cristina Martin Perez and published by Springer Nature. This book was released on 2022-02-09 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for Higgs Boson Pair Production in the bb Decay Channel written by Luca Cadamuro and published by Springer. This book was released on 2018-12-06 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying to Tau Pairs in Pp Collisions at Sqrt s written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for neutral MSSM Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 inverse picobarns recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the MSSM parameter space.

Download or read book Response of the High Granularity Calorimeter HGCAL and Characterisation of the Higgs Boson written by Matteo Bonanomi and published by Springer Nature. This book was released on 2023-05-23 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 a high-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.

Download or read book The Higgs Boson Discovery at the Large Hadron Collider written by Roger Wolf and published by Springer. This book was released on 2015-05-18 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the field of Higgs boson physics. It offers the first in-depth review of the complete results in connection with the discovery of the Higgs boson at CERN’s Large Hadron Collider and based on the full dataset for the years 2011 to 2012. The fundamental concepts and principles of Higgs physics are introduced and the important searches prior to the advent of the Large Hadron Collider are briefly summarized. Lastly, the discovery and first mensuration of the observed particle in the course of the CMS experiment are discussed in detail and compared to the results obtained in the ATLAS experiment.

Download or read book Search for a Heavy Neutral Higgs Boson Decaying Into Tau Pairs with the CMS Experiment at the LHC written by Luigi Calligaris and published by . This book was released on 2015 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Search for Heavy Neutral Higgs Bosons Decaying Into with the CMS Experiment as Predicted in Minimal Supersymmetric Standard Model of Particle Physics written by Olena Hlushchenko and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Search for the Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model with the ATLAS Detector at the Large Hadron Collider written by John Stakely Keller and published by . This book was released on 2013 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM), produced in proton-proton collisions recorded by the ATLAS detector, is presented. The data correspond to an integrated luminosity of 20.3 fb−1, with a center of mass energy of 8 TeV. The search focuses on final states where the Higgs bosons decay into a [tau]+[tau]− pair, with one [tau] lepton decaying leptonically and the other hadronically. Two analyses are performed which separately target low-mass and high-mass Higgs bosons, with the former divided into two sub-channels based on the presence or absence of a b-jet in final state. No evidence of new Higgs bosons is found, and upper limits are set on the cross-section times branching ratio of such Higgs bosons, and on the MSSM parameters m [Alpha] and tan [Beta].

Download or read book Search for the Standard Model Higgs Boson in the H ZZ l l qq Decay Channel at CMS written by Francesco Pandolfi and published by Springer Science & Business Media. This book was released on 2013-08-15 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for Beyond the Standard Model Physics at the CMS Experiment written by Leonardo Sala and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Neutral MSSM Higgs Bosons Decaying to Pairs of tau Leptons at square Root of S written by Evan Klose Friis and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for the Higgs boson, a new particle predicted by a theory called the minimal supersymmetric extension to the standard model (MSSM). The standard model of particle physics, the MSSM, and Higgs boson phenomenology are introduced briefly. The search presented in this thesis uses a single final state configuration, in which the Higgs boson decays to two tau leptons, with one tau decaying to a muon and neutrinos, and the other decaying to pions and a single neutrino. Two new methods are introduced in this analysis, the Tau Neural Classifier tau identification algorithm, and the Secondary Vertex fit tau pair mass reconstruction method. Both methods are discussed in detail. The analysis uses the 2010 dataset from the Compact Muon Solenoid (CMS) experiment, which contains 36 pb−1 of integrated luminosity at a center of mass energy of 7 TeV. In total, 573 events are selected in the analysis. We fit the observed tau pair mass spectrum and measure the composition of the events. The result is compatible with the standard model expectation. No excess of signal events is observed, and we set an upper limit on the cross section times branching ratio of a Higgs boson. This limit is interpreted in the parameter space of the MSSM.