Search for Higgs Bosons Beyond the Standard Model in Proton-Proton Collisions with the CMS Detector at the LHC

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (916 download)

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Book Synopsis Search for Higgs Bosons Beyond the Standard Model in Proton-Proton Collisions with the CMS Detector at the LHC by : Felix Frensch

Download or read book Search for Higgs Bosons Beyond the Standard Model in Proton-Proton Collisions with the CMS Detector at the LHC written by Felix Frensch and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Discovery of the Higgs Boson and a Search for Beyond the Standard Model Physics in ZZ Decays Using the CMS Detector at the LHC

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (865 download)

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Book Synopsis Discovery of the Higgs Boson and a Search for Beyond the Standard Model Physics in ZZ Decays Using the CMS Detector at the LHC by :

Download or read book Discovery of the Higgs Boson and a Search for Beyond the Standard Model Physics in ZZ Decays Using the CMS Detector at the LHC written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the pp to ZZ 6́2 llll final state is conducted using 19.6 inverse femtobarn of 8 TeV proton-proton collisions at the LHC using the CMS detector. The Standard Model pp 6́2 ZZ production cross section is measured to be 7.7+0.5 -0.5 (stat.) +0.6 -0.5(sys.) ± 0.3(lumi) pb. Evidence of a new Higgs-like boson is observed with a significance of 6.1ï3 at 126 GeV. 95% confidence level upper limits are set on the neutral anomalous triple gauge couplings; -0.004

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

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Publisher : Springer Nature
ISBN 13 : 3030902064
Total Pages : 291 pages
Book Rating : 4.0/5 (39 download)

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Book Synopsis Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC by : Cristina Martin Perez

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.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

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Publisher : Frontiers Media SA
ISBN 13 : 2889639908
Total Pages : 180 pages
Book Rating : 4.8/5 (896 download)

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Book Synopsis Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? by : Roman Pasechnik

Download or read book Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

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

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Publisher : Springer Science & Business Media
ISBN 13 : 3319009036
Total Pages : 137 pages
Book Rating : 4.3/5 (19 download)

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Book Synopsis Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS by : Francesco Pandolfi

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.

Search for the Standard Model Higgs Boson in the Dimuon Final State in Proton-proton Collisions at a Center-of-mass Energy of 13tev with the Cms Detector

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Publisher :
ISBN 13 : 9780355471915
Total Pages : 141 pages
Book Rating : 4.4/5 (719 download)

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Book Synopsis Search for the Standard Model Higgs Boson in the Dimuon Final State in Proton-proton Collisions at a Center-of-mass Energy of 13tev with the Cms Detector by : Elizabeth Michelle Goens Kennedy

Download or read book Search for the Standard Model Higgs Boson in the Dimuon Final State in Proton-proton Collisions at a Center-of-mass Energy of 13tev with the Cms Detector written by Elizabeth Michelle Goens Kennedy and published by . This book was released on 2017 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a search for the 125 GeV Standard Model Higgs boson in the opposite-sign dimuon decay channel. The search is performed in 35.92 fb-1 of proton-proton collision data taken at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. Results are found by combining several topological categories. The resulting 95% confidence level upper limit on [sigma]/[sigma] subcript [SM H→ [mu]+[mu]-] is 2.41 × SM expected and 2.79 × SM observed.

Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider

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Publisher : Springer Nature
ISBN 13 : 3030254747
Total Pages : 103 pages
Book Rating : 4.0/5 (32 download)

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Book Synopsis Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider by : Ulascan Sarica

Download or read book Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider written by Ulascan Sarica and published by Springer Nature. This book was released on 2019-09-26 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis documents the measurement of lifetime, width, mass, and couplings to two electroweak bosons of the recently-discovered Higgs boson using data from the CMS experiment at the Large Hadron Collider. Both on-shell (at the mass of around 125 GeV) and off-shell (above 200 GeV) Higgs boson production is studied and an excess of off-shell production with significance above two standard deviations is observed for the first time. The latter is a qualitative new way to study the Higgs field, responsible for generation of mass of all the known elementary particles. In addition, phenomenological tools have been developed with the Monte Carlo event generator and matrix element techniques for an optional analysis of LHC data. Optimization of the CMS data with careful alignment of the silicon tracker is also presented.

Fishing for New Physics with Massive Neutral Dibosons

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ISBN 13 :
Total Pages : 201 pages
Book Rating : 4.:/5 (91 download)

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Book Synopsis Fishing for New Physics with Massive Neutral Dibosons by : Matthew Ervin Chasco

Download or read book Fishing for New Physics with Massive Neutral Dibosons written by Matthew Ervin Chasco and published by . This book was released on 2014 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics is a theory describing the fundamental interactions and properties of subatomic particles. A key feature is its ability to explain particle mass through the Higgs mechanism, and a by-product of this mechanism is the Higgs boson. The discovery of the Higgs boson, in 2012 at CERN, completed the Standard Model particle zoo, but observed phenomena, like dark matter, remain unexplained. The analyses presented explore proton-proton collison events resulting in a Z boson plus missing transverse energy (MET). The motivation for this is to investigate two processes: Standard Model (SM) ZZ production, and beyond Standard Model (BSM) ZH production, in particular the ZZ to 2l2nu and ZH to 2l + H(inv) channels. The place-holder H(inv) is for all Higgs boson decay modes resulting in undetected "invisible" particles, which may branch to new physics, like dark matter particles. The data used are from Run 1 (2011-2012) of CMS, where proton-proton collisions at 7 TeV and 8 TeV were delivered by the LHC. The Compact Muon Solenoid (CMS) is a general-purpose detector located along the Large Hadron Collider (LHC), which is a particle accelerator at CERN in Geneva, Switzerland. To extract these signals containing real MET from background containing fake mismeasured MET, a new "reduced MET" variable is constructed and optimized. This assists in the measurement of the ZZ production cross section. The results of the exclusive ZZ to 2l2nu cross section measurement are 201+82/-69 fb and 264+81/-64 fb from the 7 and 8 TeV portions of Run 1 data, respectively. Bayesian unfolding is used to measure a cross section of 224+68/-70 fb from the 8 TeV data. These results both agree with next-to-leading order predictions from the Standard Model. The differential cross section as a function of transverse momentum of the Z boson is also measured from unfolding, for the purpose of providing a way to compare data to new theories. To distinguish ZH to 2l + H(inv) from ZZ to 2l2nu a machine learning algorithm is used with physical variables as the input. A shape analysis is performed on the resulting distribution, and an upper limit is placed at 95% C.L. on the invisible branching fraction of the Higgs boson. For a Higgs boson with a Standard Model cross section and mass of 125 GeV, the observed limit on the branching fraction is 52% and the expected is 49%. Considering a mass spectrum of 115-200 GeV, a fully invisible Higgs is excluded for masses below 163 GeV.

Scalar Boson Decays to Tau Leptons

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Publisher : Springer
ISBN 13 : 3319706500
Total Pages : 282 pages
Book Rating : 4.3/5 (197 download)

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Book Synopsis Scalar Boson Decays to Tau Leptons by : Cécile Caillol

Download or read book Scalar Boson Decays to Tau Leptons written by Cécile Caillol and published by Springer. This book was released on 2017-11-15 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

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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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (137 download)

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Book Synopsis 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 by : Jake Rosenzweig

Download or read book 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 published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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, 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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Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (971 download)

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Book Synopsis 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 by : Hongtao Yang

Download or read book 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 published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Particle Physics Reference Library

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Publisher : Springer Nature
ISBN 13 : 3030382079
Total Pages : 632 pages
Book Rating : 4.0/5 (33 download)

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Book Synopsis Particle Physics Reference Library by : Herwig Schopper

Download or read book Particle Physics Reference Library written by Herwig Schopper and published by Springer Nature. This book was released on 2020 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access

A Search for Charged Higgs Bosons in Multilepton Final States and a Measurement of [p][p] to WZ to [l][v][l]'[l]' with the CMS Detector at the LHC

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Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (974 download)

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Book Synopsis A Search for Charged Higgs Bosons in Multilepton Final States and a Measurement of [p][p] to WZ to [l][v][l]'[l]' with the CMS Detector at the LHC by : Devin Nathaniel Taylor

Download or read book A Search for Charged Higgs Bosons in Multilepton Final States and a Measurement of [p][p] to WZ to [l][v][l]'[l]' with the CMS Detector at the LHC written by Devin Nathaniel Taylor and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a search for a doubly-charged Higgs boson in three and four lepton final states. The two production modes considered are the associated production mode with a doubly-charged Higgs boson produced in association with a singly-charged Higgs boson and the pair production mode with the simultaneous production of two doubly-charged Higgs bosons. The search is performed with 12.9 fb-1 of square root s = 13 TeV proton-proton collision data collected with the Compact Muon Solenoid at the Large Hadron Collider. In addition, this thesis presents the first measurement of the WZ production cross section in proton-proton collisions at square root s = 13 TeV. The measurement is performed in the WZ to [l][v][l]'[l]' decay mode where [l], [l]' = e, [mu] with an integrated luminosity of 2.3 fb-1.

A Beauty-ful Boson

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Publisher : Springer Nature
ISBN 13 : 3031200136
Total Pages : 229 pages
Book Rating : 4.0/5 (312 download)

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Book Synopsis A Beauty-ful Boson by : Giulia Di Gregorio

Download or read book A Beauty-ful Boson written by Giulia Di Gregorio and published by Springer Nature. This book was released on 2023-01-01 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis described in this thesis is the search for the Higgs boson, decaying into bb pair, in the associated production with a vector boson, in the extreme Higgs boson transverse momentum region where the Higgs boson is reconstructed using the large-R jet technique. The use of the large-R jets allows to add a part of the phase space unexplored so far, which is particularly sensitive to possible new physics. The analysed data have been collected at LHC by the ATLAS detector between 2015 and 2018 at a centre-of-mass energy of √s = 13 TeV. The same dataset has been used to perform the differential pp → ZH and pp → WH cross-section measurements used to extract the information on the Higgs couplings and to put limits on Beyond the Standard Model effects. Furthermore the analysis has been re-used to perform a cross-section measurement of the diboson ZZ and WZ processes because the diboson and the Higgs processes have a similar topology. For the first time the ZZ(bb) and WZ(bb) cross-sections are measured at √s = 13 TeV and the observed cross-section measurements are consistent with the Standard Model predictions.

Physics with Photons Using the ATLAS Run 2 Data

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Publisher : Springer
ISBN 13 : 3030243702
Total Pages : 265 pages
Book Rating : 4.0/5 (32 download)

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Book Synopsis Physics with Photons Using the ATLAS Run 2 Data by : Stefano Manzoni

Download or read book Physics with Photons Using the ATLAS Run 2 Data written by Stefano Manzoni and published by Springer. This book was released on 2019-08-02 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this book is based on the proton-proton collision data from the Large Hadron Collider at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector in 2015 and 2016. The research program of the ATLAS experiment includes the precise measurement of the parameters of the Standard Model, and the search for signals of physics beyond the SM. Both these approaches are pursued in this thesis, which presents two different analyses: the measurement of the Higgs boson mass in the di-photon decay channel, and the search for production of supersymmetric particles (gluinos, squarks or winos) in a final state containing two photons and missing transverse momentum. Finally, ATLAS detector performance studies, which are key ingredients for the two analyses outlined before, are also carried out and described.

Search for Light Bosons in Decays of the 125 GeV Higgs Boson in Proton-proton Collisions at Sqrt(s)

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (971 download)

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Book Synopsis Search for Light Bosons in Decays of the 125 GeV Higgs Boson in Proton-proton Collisions at Sqrt(s) by :

Download or read book Search for Light Bosons in Decays of the 125 GeV Higgs Boson in Proton-proton Collisions at Sqrt(s) written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for decays beyond the standard model of the 125 GeV Higgs bosons to a pair of light bosons, based on models with extended scalar sectors. Light boson masses between 5 and 62.5 GeV are probed in final states containing four tau leptons, two muons and two b quarks, or two muons and two tau leptons. The results are from data in proton-proton collisions corresponding to an integrated luminosity of 19.7 inverse-femtobarns, accumulated by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV. No evidence for such exotic decays is found in the data. Upper limits are set on the product of the cross section and branching fraction for several signal processes. The results are also compared to predictions of two-Higgs-doublet models, including those with an additional scalar singlet.

Search for Charged Higgs Bosons in Tau-lepton Final States with 139 Inverse Femtobarns of Proton-proton Collision Data Recorded at a Centre of Mass Energy of 13 TeV with the ATLAS Detector

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Publisher :
ISBN 13 :
Total Pages : 240 pages
Book Rating : 4.:/5 (116 download)

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Book Synopsis Search for Charged Higgs Bosons in Tau-lepton Final States with 139 Inverse Femtobarns of Proton-proton Collision Data Recorded at a Centre of Mass Energy of 13 TeV with the ATLAS Detector by : Sina Bahrasemani

Download or read book Search for Charged Higgs Bosons in Tau-lepton Final States with 139 Inverse Femtobarns of Proton-proton Collision Data Recorded at a Centre of Mass Energy of 13 TeV with the ATLAS Detector written by Sina Bahrasemani and published by . This book was released on 2019 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Higgs boson, with a measured mass of approximately $125~GeV$, has been studied extensively since its discovery in 2012 at the Large Hadron Collider. This discovery opens the question of whether the Higgs boson of the Standard Model (SM) is the only scalar particle of Nature or it belongs to a larger scalar sector, as predicted in many Beyond the Standard Model (BSM) theories. Therefore, observation of charged Higgs bosons would indicate new physics. This thesis presents results of a search for a charged Higgs boson in the mass range $80~GeV$ to $3~TeV$, through tau-lepton final states. The search is performed using proton-proton collisions data at $\sqrt{s}=13~\mbox{TeV}$, collected with the ATLAS experiment, during 2015 to 2018. The final results are interpreted in the context of the Minimal SuperSymmetric Standard Model (MSSM) benchmark scenarios. In these scenarios, charged Higgs bosons coupling to tau-lepton are enhanced for some parts of the search phase space, thus increasing the chance of their discovery. No significant excess of events above the expected background from the Standard Model processes is observed. Therefore, upper limits on the charged Higgs boson production cross section times its branching ratio to tau-lepton and its associated neutrino are set at a 95\% Confidence Level. The results are also interpreted in the context of the hMSSM and $m^{mod -}_{h}$ benchmark scenarios of the MSSM. Due to the enhancement of the charged Higgs boson coupling to tau-leptons at high values of the $\tan\beta$ parameter of the MSSM, it is possible to exclude the high $\tan\beta$ region in the $M_{H^{\pm}}$--$\tan\beta$ parameter space. In this work, $\tan\beta$ values around 60 are excluded up to a charged Higgs boson mass of $1400~\GeV$. Furthermore, in the low mass region, below $170~GeV$, all values of $\tan\beta$ in range 1--60 are excluded at 95\% confidence level.