Measurement of Higgs Boson Production Via Vector Boson Fusion in Decays Into W Bosons with the ATLAS Detector
Author: Johanna Bronner
Publisher:
Published: 2014
Total Pages: 214
ISBN-13:
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Discovery and Measurement of the Higgs Boson in the WW Decay Channel
Author: David Hall
Publisher: Springer
Published: 2015-06-15
Total Pages: 175
ISBN-13: 3319199897
DOWNLOAD EBOOKThis 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.
Search for the Higgs Boson in the Vector Boson Fusion Channel at the ATLAS Detector
Author: Eric Ouellette
Publisher: Springer
Published: 2015-01-20
Total Pages: 114
ISBN-13: 3319135996
DOWNLOAD EBOOKThis 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.
Precision Measurements of Higgs Boson Production in Decays to W Bosons Using Machine Learning with the ATLAS Experiment
Author: Benjamin Jäger
Publisher:
Published: 2022
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKThe 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.
A Beauty-ful Boson
Author: Giulia Di Gregorio
Publisher: Springer Nature
Published: 2023-01-01
Total Pages: 229
ISBN-13: 3031200136
DOWNLOAD EBOOKThe 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.
Discovery and Measurement of the Higgs Boson in the WW Decay Channel
Author: David Hall
Publisher:
Published: 2015
Total Pages:
ISBN-13: 9783319199900
DOWNLOAD EBOOKThis 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.
Study of (W/Z)H Production and Higgs Boson Couplings Using H2!W W * Decays with the ATLAS Detector
Author:
Publisher:
Published: 2015
Total Pages:
ISBN-13:
DOWNLOAD EBOOKA 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.
Study of (W/Z)H Production and Higgs Boson Couplings Using H2!WW* Decays with the ATLAS Detector
Author:
Publisher:
Published: 2015
Total Pages: 65
ISBN-13:
DOWNLOAD EBOOKA 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.
Measurements of Higgs Boson Production and Couplings in Diboson Final States with the ATLAS Detector at the LHC.
Author:
Publisher:
Published: 2013
Total Pages:
ISBN-13:
DOWNLOAD EBOOKMeasurements 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.
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
Author: [Study Group] ATLAS Collaboration CERN
Publisher:
Published: 2022
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAbstract: 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
