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Measurement Of Higgs Boson Production Via Vector Boson Fusion In Decays Into W Bosons With The Atlas Detector
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Book Synopsis Measurement of Higgs Boson Production Via Vector Boson Fusion in Decays Into W Bosons with the ATLAS Detector by : Johanna Bronner
Download or read book Measurement of Higgs Boson Production Via Vector Boson Fusion in Decays Into W Bosons with the ATLAS Detector written by Johanna Bronner and published by . This book was released on 2014 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Search for the Higgs Boson in the Vector Boson Fusion Channel at the ATLAS Detector by : Eric Ouellette
Download or read book Search for the Higgs Boson in the Vector Boson Fusion Channel at the ATLAS Detector written by Eric Ouellette and published by Springer. This book was released on 2015-01-20 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Thesis describes the first measurement of, and constraints on, Higgs boson production in the vector boson fusion mode, where the Higgs decays to b quarks (the most common decay channel), at the LHC. The vector boson fusion mode, in which the Higgs is produced simultaneously with a pair of quark jets, provides an unparalleled opportunity to study the detailed properties of the Higgs, including the possibility of parity and CP violation, as well as its couplings and mass. It thus opens up this new field of study for precision investigation as the LHC increases in energy and intensity, leading the way to this new and exciting arena of precision Higgs research.
Book Synopsis Discovery and Measurement of the Higgs Boson in the WW Decay Channel by : David Hall
Download or read book Discovery and Measurement of the Higgs Boson in the WW Decay Channel written by David Hall and published by Springer. This book was released on 2015-06-15 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the stand-alone discovery and measurement of the Higgs boson in its decays to two W bosons using the Run-I ATLAS dataset. This is the most precise measurement of gluon-fusion Higgs boson production and is among the most significant results attained at the LHC. The thesis provides an exceptionally clear exposition on a complicated analysis performed by a large team of researchers. Aspects of the analysis performed by the author are explained in detail; these include new methods for evaluating uncertainties on the jet binning used in the analysis and for estimating the background due to associated production of a W boson and an off-shell photon. The thesis also describes a measurement of the WW cross section, an essential background to Higgs boson production. The primary motivation of the LHC was to prove or disprove the existence of the Higgs boson. In 2012, CERN announced this discovery and the resultant ATLAS publication contained three decay channels: gg, ZZ, and WW.
Book Synopsis Precision Measurements of Higgs Boson Production in Decays to W Bosons Using Machine Learning with the ATLAS Experiment by : Benjamin Jäger
Download or read book Precision Measurements of Higgs Boson Production in Decays to W Bosons Using Machine Learning with the ATLAS Experiment written by Benjamin Jäger and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Higgs boson is a unique tool in the search for the fundamental laws of nature, as it is connected to many of the open fundamental questions the Standard Model (SM) of particle physics cannot answer. Precision measurements of the properties of the Higgs boson, including its interactions with other fundamental particles, provide a powerful tool to test the predictions of the SM and possibly find deviations from them. As part of a broad Higgs boson physics program at the Large Hadron Collider (LHC), this thesis presents cross-section measurements of Higgs boson production via gluon fusion (ggF) and vector-boson fusion (VBF) in decays to W bosons. The H -> WW* decay is the second most likely decay of the Higgs boson and, in the VBF production mode, the most sensitive channel to measure the coupling of the Higgs boson to vector bosons at the LHC. The measurement is based on pp collisions at a center-of-mass energy of \sqrt{s} = 13 TeV recorded by the ATLAS experiment at the LHC between 2015 and 2018, corresponding to an integrated luminosity of 139 / fb. The measurements of the inclusive ggF and VBF cross sections times branching fraction result in 12.0 +-1.4 pb and 0.75 +0.19 -0.16 pb, respectively. In addition, Higgs boson production is measured in 11 exclusive kinematic regions. All results are found to be consistent with their corresponding SM predictions. The H -> WW* analysis is also an important input to combined Higgs boson measurements, which provide some of the most precise measurements of Higgs boson interactions to date and are briefly summarized in this work. The measurement of the VBF, H -> WW* process is drastically improved over previous results by the implementation of a binary classifier based on a deep neural network (DNN) that distinguishes the VBF, H -> WW* signal from other physical processes. The development and optimization of the DNN are presented in this thesis. This thesis also presents the measurement of the jet energy resolution, which is essential for many physics analyses performed with the ATLAS experiment, such as the H -> WW* analysis, due to the abundance of jets in pp collisions.
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.
Book Synopsis Discovery and Measurement of the Higgs Boson in the WW Decay Channel by : David Hall
Download or read book Discovery and Measurement of the Higgs Boson in the WW Decay Channel written by David Hall and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the stand-alone discovery and measurement of the Higgs boson in its decays to two W bosons using the Run-I ATLAS dataset. This is the most precise measurement of gluon-fusion Higgs boson production, and is among the most significant results attained at the LHC. The thesis provides an exceptionally clear exposition on a complicated analysis performed by a large team of researchers. Aspects of the analysis performed by the author are explained in detail; these include new methods for evaluating uncertainties on the jet binning used in the analysis, and for estimating the background due to associated production of a W boson and an off-shell photon. The thesis also describes a measurement of the WW cross section, an essential background to Higgs boson production. The primary motivation of the LHC was to prove or disprove the existence of the Higgs boson. In 2012, CERN announced this discovery and the resultant ATLAS publication contained three decay channels: gg, ZZ, and WW.
Book Synopsis Measurements of Higgs Boson Production and Couplings in Diboson Final States with the ATLAS Detector at the LHC. by :
Download or read book Measurements of Higgs Boson Production and Couplings in Diboson Final States with the ATLAS Detector at the LHC. written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H→[gamma][gamma], H→ZZ{sup *}→4l and H→WW{sup *}→l[nu]l[nu]. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of {radical s}=7 TeV and {radical s}=8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.
Book Synopsis Evidence for the Production of the Standard Model Higgs Boson Produced Via Vector Boson Fusion in the WW* Channel at the ATLAS Detector by : Koos van Nieuwkoop
Download or read book Evidence for the Production of the Standard Model Higgs Boson Produced Via Vector Boson Fusion in the WW* Channel at the ATLAS Detector written by Koos van Nieuwkoop and published by . This book was released on 2017 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2012, the ATLAS and CMS experiments at CERN's Large Hadron Collider announced they had each observed a new particle with a mass of about 125 GeV/c^2. Given the available data, the properties of this particle are consistent with the Higgs boson predicted by the Standard Model of particle physics (SM). The Higgs boson, as proposed within the SM, is the simplest manifestation of the Brout-Englert-Higgs mechanism. This discovery was driven by the gluon fusion (ggF) production mode, the dominant Higgs boson production mechanism at the LHC. The SM also predicts that the Higgs boson can be produced by the fusion of two weak vector bosons (VBF). Measuring VBF Higgs boson production is an important test of the SM but it is challenging to measure given its cross section is an order of magnitude smaller than that of ggF. After H->bb, H->WW* is the dominant decay channel for the SM Higgs boson at 125 GeV/c^2 and is therefore a promising channel to measure its properties. In addition, the VBF H->WW* search channel makes it possible to probe the exclusive coupling of the Higgs boson to the weak vector bosons. Precise measurements of these coupling strengths make it possible to constrain new models of physics beyond the SM. Despite its relatively large branching ratio, H->WW*->lnln is a challenging channel to search for the Higgs boson because of the neutrinos in the final state which are not directly detectable by the ATLAS detector. Consequently, it is not possible to fully reconstruct the mass of the WW system. Furthermore, there are several backgrounds that have the same signature in the detector as the signal. Top quark pair production is the largest background in this analysis. A multivariate analysis technique, based on an eight-variable boosted decision tree (BDT), is used to search for VBF H->WW*->lnln in the Run-I data and a subset of the Run-II data. This analysis provides the first evidence for VBF H->WW*->lnln with a significance of 3.2 standard deviations in Run-I and 1.9 standard deviations in Run-II. The measured signal strength relative to the rate predicted by the SM for VBF H->WW*->lnln is 1.3 +/- 0.5 using the Run-I data, and 1.7 +1.1/-0.9 using a fraction of the Run-II data.
Book Synopsis Study of (W/Z)H Production and Higgs Boson Couplings Using H2!WW* Decays with the ATLAS Detector by :
Download or read book Study of (W/Z)H Production and Higgs Boson Couplings Using H2!WW* Decays with the ATLAS Detector written by and published by . This book was released on 2015 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for Higgs boson production in association with a W or Z boson, in the H2!W W* decay channel, is performed with a data sample collected with the ATLAS detector at the LHC in proton-proton collisions at centre-of-mass energies [arrow]"=7 TeV and 8 TeV, corresponding to integrated luminosities of 4.5 fb-1 and 20.3 fb-1, respectively. The WH production mode is studied in two-lepton and three-lepton final states, while two- lepton and four-lepton final states are used to search for the ZH production mode. The observed significance, for the combined WH and ZH production, is 2.5 standard deviations while a significance of 0.9 standard deviations is expected in the Standard Model Higgs boson hypothesis. The ratio of the combined WH and ZH signal yield to the Standard Model expectation, [mu]VH, is found to be [mu]VH = 3.0-1.1+1.3 (stat.)-0.7+1.0 (sys.) for the Higgs boson mass of 125.36 GeV. WH and ZH production modes are also combined with the gluon fusion and vector boson fusion production modes studied in the H 2!W W* 2!l[nu]l[nu] decay channel, resulting in an overall observed significance of 6.5 standard deviations and [mu]ggF+VBF+VH=1.16-0.15+0.16 (stat.) -0.15+0.18 (sys.). The results are interpreted in terms of scaling factors of the Higgs boson couplings to vector bosons ([kappa]V) and fermions ([kappa]F); the combined results are.
Book Synopsis Study of (W/Z)H Production and Higgs Boson Couplings Using H2!W W * Decays with the ATLAS Detector by :
Download or read book Study of (W/Z)H Production and Higgs Boson Couplings Using H2!W W * Decays 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: A search for Higgs boson production in association with a W or Z boson, in the H2!W W * decay channel, is performed with a data sample collected with the ATLAS detector at the LHC in proton-proton collisions at centre-of-mass energies \(\sqrt{s}=7 \) TeV and 8 TeV, corresponding to integrated luminosities of 4.5 fb-1 and 20.3 fb-1, respectively. The WH production mode is studied in two-lepton and three-lepton final states, while two- lepton and four-lepton final states are used to search for the ZH production mode. The observed significance, for the combined W H and ZH production, is 2.5 standard deviations while a significance of 0.9 standard deviations is expected in the Standard Model Higgs boson hypothesis. The ratio of the combined W H and ZH signal yield to the Standard Model expectation, [mu]V H, is found to be [mu] V H = 3.0-1.1+1.3 (stat.)-0.7 +1.0 (sys.) for the Higgs boson mass of 125.36 GeV. The W H and ZH production modes are also combined with the gluon fusion and vector boson fusion production modes studied in the H 2!W W * 2!l[nu]l[nu] decay channel, resulting in an overall observed significance of 6.5 standard deviations and [mu]ggF + VBF + VH = 1.16-0.15+0.16 (stat.) -0.15+0.18 (sys.). The results are interpreted in terms of scaling factors of the Higgs boson couplings to vector bosons ([kappa]V) and fermions ([kappa]F); the combined results are.
Book Synopsis Search for the Higgs Boson in the Process H 2!ZZ 2!llv Produced Via Vector-boson Fusion with the ATLAS Detector by : Clive Andrew Edwards
Download or read book Search for the Higgs Boson in the Process H 2!ZZ 2!llv Produced Via Vector-boson Fusion with the ATLAS Detector written by Clive Andrew Edwards and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The search potential of a Standard Model Higgs boson in the Vector Boson Fusion production mechanism with Higgs boson decaying to two leptons and two neutrinos via decay to two Z bosons with the ATLAS detector is investigated. The ATLAS detector is a general purpose detector in operation at CERN measuring proton-proton collisions produced by the Large Hadron Collider. This channel has been shown to have high sensitivity at large Higgs mass, where large amounts of missing energy in the signal provide good discrimination over expected backgrounds. This work takes a first look at whether the sensitivity of this channel may be improved using the remnants of the vector boson fusion process to pro- vide extra discrimination, particularly at lower mass where sensitivity of the main analysis is reduced because of lower missing energy. Simulated data samples at centre of mass energy 7 Te V are used to derive signal significances over the mass range between 200-600 Ge V / c2. Because of varying signal properties with mass, a low and a high mass event selection were developed and optimized. A comparison between simulated and real data (collected in 2010) is made of variables used in the analysis and the effect of pileup levels corresponding to those in the 2010 data is investigated. Possible methods to estimate some of the main backgrounds to this search are described and discussed. The impact • of important theoretical and detector related systematics are taken into account. Final results are presented in the form of 95 % Confidence Level exclusion limits on the signal cross section relative to the SM prediction as a function of Higgs boson mass, based on an integrated luminosity of 33.4 pb -1 of data collected during 2010.
Book Synopsis Search for Invisible Higgs-boson Decays in Events with Vector-boson Fusion Signatures Using 139 Fb−1 of Proton-proton Data Recorded by the ATLAS Experiment by : [Study Group] ATLAS Collaboration CERN
Download or read book Search for Invisible Higgs-boson Decays in Events with Vector-boson Fusion Signatures Using 139 Fb−1 of Proton-proton Data Recorded by the ATLAS Experiment written by [Study Group] ATLAS Collaboration CERN and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A direct search for Higgs bosons produced via vector-boson fusion and subsequently decaying into invisible particles is reported. The analysis uses 139 fb−1 of pp collision data at a centre-of-mass energy of s√ = 13 TeV recorded by the ATLAS detector at the LHC. The observed numbers of events are found to be in agreement with the background expectation from Standard Model processes. For a scalar Higgs boson with a mass of 125 GeV and a Standard Model production cross section, an observed upper limit of 0.145 is placed on the branching fraction of its decay into invisible particles at 95% confidence level, with an expected limit of 0.103. These results are interpreted in the context of models where the Higgs boson acts as a portal to dark matter, and limits are set on the scattering cross section of weakly interacting massive particles and nucleons. Invisible decays of additional scalar bosons with masses from 50 GeV to 2 TeV are also studied, and the derived upper limits on the cross section times branching fraction decrease with increasing mass from 1.0 pb for a scalar boson mass of 50 GeV to 0.1 pb at a mass of 2 TeV
Book Synopsis Observation and Measurement of Higgs Boson Decays to WW* with the ATLAS Detector by :
Download or read book Observation and Measurement of Higgs Boson Decays to WW* 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: We report the observation of Higgs boson decays to WW* based on an excess over background of 6.1 standard deviations in the dilepton final state, where the Standard Model expectation is 5.8 standard deviations. Evidence for the vector-boson fusion (VBF) production process is obtained with a significance of 3.2 standard deviations. The results are obtained from a data sample corresponding to an integrated luminosity of 25 fb-1 from [arrow]"=7 and 8 TeV pp collisions recorded by the ATLAS detector at the LHC. For a Higgs boson mass of 125.36 GeV, the ratio of the measured value to the expected value of the total production cross section times branching fraction is 1.09+0.16-0.15(stat)+0.17-0.14(syst). The corresponding ratios for the gluon fusion and vector-boson fusion production mechanisms are 1.02 " 0.19(stat)+0.22-0.18(syst) and 1.27+0.44-0.40(stat)+0.30-0.21(syst), respectively. At [arrow]"=8 TeV, the total production cross sections are measured to be [sigma](gg 2!>H 2!WW*)=4.6"0.9(stat)+0.8-0.7(syst) pb and [sigma](VBF H 2!W*)=0.51+0.17-0.15(stat)+0.13-0.08(syst) pb. The fiducial cross section is determined for the gluon-fusion process in exclusive final states with 0 or one associated jet.
Book Synopsis ATLAS Measurements of the Higgs Boson Coupling to the Top Quark in the Higgs to Diphoton Decay Channel by : Jennet Elizabeth Dickinson
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.
Book Synopsis Measurement of Vector Boson Pair Production Using Hadronic Decays of High Transverse Momentum W and Z Bosons at the ATLAS Detector by : David Peter Wallis Freeborn
Download or read book Measurement of Vector Boson Pair Production Using Hadronic Decays of High Transverse Momentum W and Z Bosons at the ATLAS Detector written by David Peter Wallis Freeborn and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Precision Coupling Measurements of the Higgs Boson Using the H->ZZ*->4l Decay Channel by : Syed Haider Abidi
Download or read book Precision Coupling Measurements of the Higgs Boson Using the H->ZZ*->4l Decay Channel written by Syed Haider Abidi and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The coupling of the Higgs boson to other particles is probed by measuring the production cross sections at the Large Hadron Collider using the ATLAS detector. The present measurement is performed using the H->ZZ*->4l decay channel, with l= electron or muon and with datasets corresponding to various integrated luminosities. The inclusive production cross section is measured to be 1.34 +/- 0.12 pb, which is in good agreement with the predicted value of 1.33 +/- 0.08 pb. The gluon-gluon fusion, the vector boson fusion, the vector boson associated and the top associated production cross sections are measured to be 1.12 +/- 0.12 pb, 110 +/- 40 fb, 75 +61 -49 fb and 27 +26 -17 fb, respectively. The differential production cross sections are also measured using the Simplified Template cross sections framework. All measurements are in good agreement with the Standard Model predictions. These results are used to measure the Higgs boson coupling to fermions and vector bosons using the kappa-framework and to derive constraints on contributions from beyond the Standard Model physics using an effective field theory approach. No significant deviations from the Standard Model are observed.
Book Synopsis Constraints on New Phenomena Via Higgs Boson Couplings and Invisible Decays with the ATLAS Detector by :
Download or read book Constraints on New Phenomena Via Higgs Boson Couplings and Invisible Decays with the ATLAS Detector written by and published by . This book was released on 2015 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ATLAS experiment at the LHC has measured the Higgs boson couplings and mass, and searched for invisible Higgs boson decays, using multiple production and decay channels with up to 4.7 fb-1 of pp collision data at √s=7 TeV and 20.3 fb-1 at √s=8 TeV. In the current study, the measured production and decay rates of the observed Higgs boson in the [gamma][gamma], ZZ, W W , Z[gamma], bb, [tau] [tau] , and [mu][mu] decay channels, along with results from the associated production of a Higgs boson with a top-quark pair, are used to probe the scaling of the couplings with mass. The limits are set on parameters in extensions of the Standard Model including a composite Higgs boson, an additional electroweak singlet, and two-Higgs-doublet models. Together with the measured mass of the scalar Higgs boson in the [gamma][gamma] and ZZ decay modes, a lower limit is set on the pseudoscalar Higgs boson mass of mA > 370 GeV in the "hMSSM" simplified Minimal Supersymmetric Standard Model. Results from direct searches for heavy Higgs bosons are also interpreted in the hMSSM. Finally, direct searches for invisible Higgs boson decays in the vector-boson fusion and associated production of a Higgs boson with W/Z (Z → ll, W/Z → jj) modes are statistically combined to set an upper limit on the Higgs boson invisible branching ratio of 0.25. As a result, the use of the measured visible decay rates in a more general coupling fit improves the upper limit to 0.23, constraining a Higgs portal model of dark matter.
