Download or read book Measurement of the Higgs Boson Coupling Structure in Decays to Four Leptons with the ATLAS Detector written by Verena Maria Walbrecht and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Higgs Boson Production and Couplings in the Four lepton Decay Channel with the ATLAS Detector written by Stefano Zambito and published by . This book was released on 2015 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Higgs boson Coupling to Tau leptons and Combined Measurements of Higgs boson Properties at Sqrt s written by Théo Megy and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The measurement of the Higgs-boson coupling to tau-leptons, based on an integrated luminosity of 36.1 ifb recorded at a centre-of-mass energy of 13 TeV by the ATLAS detector, is presented in this thesis. The analysis considers all combinations of leptonic and hadronic decays of tau-leptons, and targets the main two production modes of the Higgs boson, gluon Fusion and Vector-Boson Fusion. The inclusive cross section of the H->tautau decay channel is measured as 3.77 +1.06-0.95 (+0.60-0.59 (Stat.) +0.87-0.74 (Syst.)) pb, which corresponds to a deviation from the background-only hypothesis with an observed (expected) significance of 4.4 (4.1) standard deviations. In addition, the measurement of cross sections in the framework of Simplified Template Cross Sections is discussed. All measurement are in agreement with predictions of the Standard Model. The combined measurement of Higgs-boson properties is also presented, based on up to 79.8 ifb of data recorded at sqrt(s) = 13 TeV by the ATLAS detector. An observation of the four main production modes (ggF, VBF, VH and ttH+tH) and of four of the five main decay channels (H->gammagamma, H->ZZ, H->WW and H->bb) of the Higgs boson is achieved. In particular, the deviation from the background-only hypothesis with an observed (expected) significance of 6.5 (5.3) standard deviations for the VBF production mode is the first observation of this process by a single experiment. Measurements in the scope of the kappa-framework and of Simplified Template Cross Sections are also discussed. All the performed measurements are compatible with the Standard-Model expectations
Download or read book The Beauty and the Boost A Higgs Boson Tale written by Brian Moser and published by Springer Nature. This book was released on 2023-09-19 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precision measurements of the Higgs boson’s properties are a powerful tool to look for deviations from the predictions of the Standard Model (SM) of particle physics. The 139/fb of proton-proton collision data which have been collected by the ATLAS experiment during Run 2 of the LHC, offer an opportunity to investigate rare Higgs-boson topologies, which are particularly sensitive to new physics scenarios but experimentally difficult to access. Several such measurements, which target Higgs-boson decays to heavy-flavour quarks, as well as their combinations are presented in this thesis. A novel analysis that measures Higgs-boson production in association with a heavy vector boson V (VH, with V=W,Z) at high energies is presented. Dedicated Higgs-boson reconstruction techniques are applied to reconstruct the highly Lorentz-boosted Higgs-boson decays into pairs of bottom quarks. The measurement is subsequently combined with a VH cross-section measurement at low and intermediate pT(V) to provide a differential cross-section measurement in kinematic fiducial volumes over the largest possible pT(V) range. All cross-section measurements agree with the SM predictions within relative uncertainties that range from 30% to 300%. The results are furthermore interpreted as limits on the parameters of a SM effective field theory. Finally, a combination of measurements of Higgs decays to heavy-flavour quarks is used to experimentally determine that the Higgs-boson coupling to charm quarks is weaker than to bottom quarks, as predicted by the SM. The target audience for the thesis are physicists and physics students, in particular those with a background in high energy physics.
Download or read book ATLAS Measurements of the Higgs Boson Coupling to the Top Quark in the Higgs to Diphoton Decay Channel written by Jennet Elizabeth Dickinson and published by Springer Nature. This book was released on 2021-11-16 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: During Run 2 of the Large Hadron Collider, the ATLAS experiment recorded proton-proton collision events at 13 TeV, the highest energy ever achieved in a collider. Analysis of this dataset has provided new opportunities for precision measurements of the Higgs boson, including its interaction with the top quark. The Higgs-top coupling can be directly probed through the production of a Higgs boson in association with a top-antitop quark pair (ttH). The Higgs to diphoton decay channel is among the most sensitive for ttH measurements due to the excellent diphoton mass resolution of the ATLAS detector and the clean signature of this decay. Event selection criteria were developed using novel Machine Learning techniques to target ttH events, yielding a precise measurement of the ttH cross section in the diphoton channel and a 6.3 $\sigma$ observation of the ttH process in combination with other decay channels, as well as stringent limits on CP violation in the Higgs-top coupling.
Download or read book Measurements of Higgs Boson Production and Couplings in the Four lepton Channel in pp Collisions at Center of mass Energies of 7 and 8 TeV with the ATLAS Detector written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Higgs boson Coupling to Tau leptons and Combined Measurements of Higgs boson Properties at square Roots s written by Théo J. Megy and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The measurement of the Higgs-boson coupling to tau-leptons, based on an integrated luminosity of 36.1 ifb recorded at a centre-of-mass energy of 13 TeV by the ATLAS detector, is presented in this thesis. The analysis considers all combinations of leptonic and hadronic decays of tau-leptons, and targets the main two production modes of the Higgs boson, gluon Fusion and Vector-Boson Fusion. The inclusive cross section of the H->tautau decay channel is measured as 3.77 +1.06-0.95 (+0.60-0.59 (Stat.) +0.87-0.74 (Syst.)) pb, which corresponds to a deviation from the background-only hypothesis with an observed (expected) significance of 4.4 (4.1) standard deviations. In addition, the measurement of cross sections in the framework of Simplified Template Cross Sections is discussed. All measurement are in agreement with predictions of the Standard Model. The combined measurement of Higgs-boson properties is also presented, based on up to 79.8 ifb of data recorded at sqrt(s) = 13 TeV by the ATLAS detector. An observation of the four main production modes (ggF, VBF, VH and ttH+tH) and of four of the five main decay channels (H->gammagamma, H->ZZ, H->WW and H->bb) of the Higgs boson is achieved. In particular, the deviation from the background-only hypothesis with an observed (expected) significance of 6.5 (5.3) standard deviations for the VBF production mode is the first observation of this process by a single experiment. Measurements in the scope of the kappa-framework and of Simplified Template Cross Sections are also discussed. All the performed measurements are compatible with the Standard-Model expectations.
Download or read book Search for the Higgs Boson Decaying to Four Leptons in the ATLAS Detector at LHC Leading to the Observation of a New Particle Compatible with the Higgs Boson written by Meng Xiao and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
Download or read book Search for the Higgs Boson Decaying to Four Leptons in the ATLAS Detector at LHC and Studies of Muon Isolation and Energy Loss written by Bruno Lenzi and published by . This book was released on 2010 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: The central subject of this thesis is the evaluation of the discovery potential of the Higgs boson through its decay into four leptons (electrons and muons) in the ATLAS experiment installed at the Large Hadron Collider (LHC). The LHC was designed to accelerate proton beams at a center of mass energy of 14~TeV and started its physics program with 7~TeV collisions in the beginning of 2010. An inclusive analysis involving all tle production modes and an exclusive one aiming at production through vector boson fusion (VBF), studied for the first time in the collaboration are presented. Both are capable of discovering the Higgs boson after a few years of LHC operation, with integrated luminosities of 30~fb[dollar]^{-1}[dollar]. The first one covers most part of a Higgs mass window from 130 to 500~GeV. The second one concentrates on masses around 180~GeV and above, exploiting ftle presence of high energy jets with large separations in pseudo-rapidity to increase the signal over background ratio. An important part of the document is devoted to the reconstruction of muon isolation and energy loss in the ATLAS calorimeters. A software package that optimized the way of treating the energy deposits was developed and tested on simulated data and cosmic-ray events, leading ta improvements in the muon momentum resolution and the distinction between muons from heavy quark and vector boson decays. As a consequence of the last result one of the dominant backgrounds to the [dollar]H \to 4\mu[dollar] channel, [dollar]Z\bbar[dollar], is expected to be reduced by almost a factor of two.
Download or read book From Discovery to Precision Measurements written by Kathleen Charlotte Whalen and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Brout Englert Higgs Boson Couplings in Its Diphoton Decay Channel with the ATLAS Detector at the LHC written by Estelle Scifo and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the Higgs boson discovery in the first LHC data, the focus is now on its properties measurement. Among these properties, its couplings are of particular importance since any deviation from the expected value can be an indication of new physics, beyond the Standard Model. This thesis is oriented towards the Higgs couplings measurements with the ATLAS experiment, using the diphoton decay channel. Selected diphoton events are classified into different categories to disentangle the five Higgs production modes by tagging the objects produced in association with the Higgs boson: two jets for the VBF production mode, lepton and missing transverse energy for the higgsstrahlung (WH and ZH), b-jets for ttH, the remaining events being mostly produced via the dominant production mode ggH. The impact of the Higgs pT modelling in the ggH production mode is also investigated. Theoretical developments provide predictions of the pT shape at NNLO+NNLL accuracy, including top and bottom mass effects in the loop up to NLO+NLL, implemented in the HRes program. A reweighting technique to take into account these latest theoretical improvements is derived, taking into consideration the correlation with the number of jets. Its impact on the final measurement is estimated to be of the order of a few percent. The final couplings results, measured at the Higgs mass obtained by the combination of the H->gamma gamma and H->ZZ*->4l channels in ATLAS (mH = 125.4 +/- 0.4 GeV) do not show any statistically significant deviation from the Standard Model. The observed signal strength mu = sigma^{obs} / sigma^{exp} is found to be: mu = 1.17^{+0.28}_{-0.25} = 1.17 +/- 0.23(stat) ^{+0.10}_{-0.08}(syst) ^{+0.12}_{-0.08}(theory). The ratio of the observed number of events in each production mode to the expected ones are measured at: mu_ggH = 1.32 +/- 0.32(stat.) ^{+0.13}_{-0.09}(syst.) ^{+0.19}_{-0.11}(theory) ; mu_VBF = 0.8 +/- 0.7(stat.) ^{+0.2}_{-0.1}(syst.) ^{+0.2}_{-0.3}(theory) ; mu_WH = 1.0 +/- 1.5(stat.) ^{+0.3}_{-0.1}(syst.) ^{+0.2}_{-0.1}(theory) ; mu_ZH = 0.1 ^{+3.6}_{-0.1}(stat.) ^{+0.7}_{-0.0}(syst.) ^{+0.1}_{-0.0}(theory) ; mu_ttH = 1.6 ^{+2.6}_{-1.8}(stat.) ^{+0.6}_{-0.4}(syst.} ^{+0.5}_{-0.2}(theory).
Download or read book Measurement of the Higgs Boson Tensor Coupling in H ZZ 4l Decays with the ATLAS Detector written by Katharina Maria Ecker and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Higgs Boson Decay to pairs in the Lepton Plus Hadrons Final State in Proton proton Collisions with the ATLAS Detector written by Jessica Kristina Liebal and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ATLAS Measurements of the Higgs Boson Coupling to the Top Quark in the Higgs to Diphoton Decay Channel written by Jennet Elizabeth Dickinson and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During Run 2 of the Large Hadron Collider, the ATLAS experiment recorded proton-proton collision events at 13 TeV, the highest energy ever achieved in a collider. Analysis of this dataset has provided new opportunities for precision measurements of the Higgs boson, including its interaction with the top quark. The Higgs-top coupling can be directly probed through the production of a Higgs boson in association with a top-antitop quark pair (ttH). The Higgs to diphoton decay channel is among the most sensitive for ttH measurements due to the excellent diphoton mass resolution of the ATLAS detector and the clean signature of this decay. Event selection criteria were developed using novel Machine Learning techniques to target ttH events, yielding a precise measurement of the ttH cross section in the diphoton channel and a 6.3 $\sigma$ observation of the ttH process in combination with other decay channels, as well as stringent limits on CP violation in the Higgs-top coupling.
Download or read book Search for Higgs Boson Decays to Beyond the Standard Model Light Bosons in Four lepton Events with the ATLAS Detector at the LHC written by Justin Chiu and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the search for the dark sector process h -> Zd Zd -> 4l in events collected by the ATLAS detector at the Large Hadron Collider in 2015--2018. In this theorized process, the Standard Model Higgs boson (h) decays to four leptons via two intermediate Beyond-the-Standard-Model particles each called Zd. This process arises from interactions of the Standard Model with a dark sector. A dark sector consists of one or more new particles that have limited or zero interaction with the Standard Model, such as the new vector boson Zd (dark photon). It could have a rich and interesting phenomenology like the visible sector (the Standard Model) and could naturally address many outstanding problems in particle physics. For example, it could contain a particle candidate for dark matter. In particular, Higgs decays to Beyond-the-Standard-Model particles are well-motivated theoretically and are not tightly constrained; current measurements of Standard Model Higgs properties permit the fraction of such decays to be as high as approximately 30%. The results of this search do not show evidence for the existence of the h -> Zd Zd -> 4l process and are therefore interpreted in terms of upper limits on the branching ratio B(h -> Zd Zd) and the effective Higgs mixing parameter kappa^prime.
Download or read book Measuring the CP Properties of the Higgs Boson in Its Decay to Leptons with the ATLAS Detector written by Sebastiano Spinali and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
