scholarly journals Measurements of Higgs boson properties using a combination of different Higgs decay channels

2019 ◽  
Author(s):  
Nicolas Morange ◽  
Keyword(s):  
Higgs Boson ◽  
Decay Channels ◽  
Higgs Decay

scholarly journals Synthesis on Heavy Higgs from the Standard Model to 2HDM and Beyond

2020 ◽  
Vol 18 ◽  
pp. 110-142
Author(s):  
Abdeljalil Habjia
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Particle Physics ◽  
Hadron Collider ◽  
Signal Strength ◽  
Beyond The Standard Model ◽  
Decay Channels ◽  
Higgs Decay ◽  
The Standard Model

In the context of particle physics, within the ATLAS and CMS experiments at large hadron collider (LHC), this work presents the discussion of the discovery of a particle compatible with the Higgs boson by the combination of several decay channels, with a mass of the order of 125.5 GeV. With increased statistics, that is the full set of data collected by the ATLAS and CMS experiments at LHC ( s1/2 = 7GeV and s1/2 = 8GeV ), the particle is also discovered individually in the channel h-->γγ with an observed significance of 5.2σ and 4.7σ, respectively. The analysis dedicated to the measurement of the mass mh and signal strength μ which is defined as the ratio of σ(pp --> h) X Br(h-->X) normalized to its Standard Model where X = WW*; ZZ*; γγ ; gg; ff. The combined results in h-->γγ channel gave the measurements: mh = 125:36 ± 0:37Gev, (μ = 1:17 ± 0:3) and the constraint on the width Γ(h) of the Higgs decay of 4.07 MeV at 95%CL. The spin study rejects the hypothesis of spin 2 at 99 %CL. The odd parity (spin parity 0- state) is excluded at more than 98%CL. Within the theoretical and experimental uncertainties accessible at the time of the analysis, all results: channels showing the excess with respect to the background-only hypothesis, measured mass and signal strength, couplings, quantum numbers (JPC), production modes, total and differential cross-sections, are compatible with the Standard Model Higgs boson at 95%CL. Although the Standard Model is one of the theories that have experienced the greatest number of successes to date, it is imperfect. The inability of this model to describe certain phenomena seems to suggest that it is only an approximation of a more general theory. Models beyond the Standard Model, such as 2HDM, MSSM or NMSSM, can compensate some of its limitations and postulate the existence of additional Higgs bosons.

scholarly journals Search for decays of the 125 GeV Higgs boson into a Z boson and a ρ or ϕ meson

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Z Boson ◽  
Branching Fractions ◽  
Proton Collision ◽  
Data Set ◽  
Proton Proton ◽  
Decay Channels ◽  
Decay Products ◽  
Upper Limits ◽  
Z Boson Decays

Abstract Decays of the 125 GeV Higgs boson into a Z boson and a ρ0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at $$ \sqrt{s} $$ s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb−1. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels.

scholarly journals Search for Heavy Higgs Bosons in Fermionic Decay Channels with CMS

2018 ◽  
Vol 46 ◽  
pp. 1860058
Author(s):  
Ye Chen
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Higgs Bosons ◽  
Final States ◽  
Centre Of Mass ◽  
Decay Channels ◽  
Upper Limits ◽  
The Standard Model ◽  
Cms Detector

Latest results of searches for heavy Higgs bosons in fermionic final states are presented using the CMS detector at the LHC. Results are based on pp collision data collected at centre-of-mass energies of 8 and 13 TeV which have been interpreted according to different extensions of the Standard Model such as MSSM, 2HDM, and NMSSM. These searches look for evidence of other scalar or pseudoscalar bosons, in addition to the observed SM-like 125 GeV Higgs boson, and set 95% confidence level upper limits in fermionic final states and benchmark models explored. The talk reviews briefly the major results obtained by the CMS Collaboration during Run I, and presents the most recent searches performed during Run II.

scholarly journals Fiducial cross sections for the lepton-pair-plus-photon decay mode in Higgs production up to NNLO QCD

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
X. Chen ◽  
T. Gehrmann ◽  
E. W. N. Glover ◽  
A. Huss
Keyword(s):  
Higgs Boson ◽  
Decay Mode ◽  
Cross Sections ◽  
Gluon Fusion ◽  
Lepton Pair ◽  
Distinctive Features ◽  
Photon Decay ◽  
Higgs Decay ◽  
Decay Products ◽  
Three Body

Abstract The rare three-body decay of a Higgs boson to a lepton-antilepton pair and a photon is starting to become experimentally accessible at the LHC. We investigate how higher-order QCD corrections to the dominant gluon-fusion production process impact on the fiducial cross sections in this specific Higgs decay mode for electrons and muons. Corrections up to NNLO QCD are found to be sizeable. They are generally uniform in kinematical variables related to the Higgs boson, but display several distinctive features in the kinematics of its individual decay products.

scholarly journals tt̄H Coupling Measurement with the ATLAS Detector at the LHC

2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
High Energy Physics ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Higgs Decay

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.

scholarly journals The second lightest CP-even Higgs boson signals in the NMSSM at the LHC

2018 ◽  
Vol 33 (10) ◽  
pp. 1850071
Author(s):  
M. M. Almarashi
Keyword(s):  
Higgs Boson ◽  
Parameter Space ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Bottom Quarks ◽  
Final States ◽  
Production Rates ◽  
Decay Channels ◽  
Text Signals

We study the signal rates of the second lightest CP-even Higgs boson, [Formula: see text], of the NMSSM produced in gluon fusion, in association with bottom quarks and in association with top quarks, which is not the SM-like Higgs boson, at the LHC. We evaluate the production rates of [Formula: see text] in the SM fermionic and bosonic final states in addition to [Formula: see text], [Formula: see text] and [Formula: see text] final states. It is observed that the size of the signal rates in some regions of the NMSSM parameter space is quite large and that could help extracting [Formula: see text] signals at the LHC through a variety of decay channels.

Sign in / Sign up

Export Citation Format

Share Document