scholarly journals Higgs boson decay into a lepton pair and a photon: A roadmap to the discovery of H→Zγ and probes of new physics

2022 ◽  
Vol 105 (1) ◽  
Author(s):  
Aliaksei Kachanovich ◽  
Ulrich Nierste ◽  
Ivan Nišandžić
Keyword(s):  
Higgs Boson ◽  
New Physics ◽  
Lepton Pair

scholarly journals Indirect $$ \mathcal{CP} $$ probes of the Higgs-top-quark interaction: current LHC constraints and future opportunities

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Henning Bahl ◽  
Philip Bechtle ◽  
Sven Heinemeyer ◽  
Judith Katzy ◽  
Tobias Klingl ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Top Quark ◽  
Decay Channel ◽  
New Physics ◽  
Current Data ◽  
Quark Interaction ◽  
The Standard Model ◽  
Vector Bosons ◽  
Selection Of

Abstract The $$ \mathcal{CP} $$ CP structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this study, all relevant inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments are used to constrain the $$ \mathcal{CP} $$ CP -nature of the top-Yukawa interaction. The model dependence of the constraints is studied by successively allowing for new physics contributions to the couplings of the Higgs boson to massive vector bosons, to photons, and to gluons. In the most general case, we find that the current data still permits a significant $$ \mathcal{CP} $$ CP -odd component in the top-Yukawa coupling. Furthermore, we explore the prospects to further constrain the $$ \mathcal{CP} $$ CP properties of this coupling with future LHC data by determining tH production rates independently from possible accompanying variations of the $$ t\overline{t}H $$ t t ¯ H rate. This is achieved via a careful selection of discriminating observables. At the HL-LHC, we find that evidence for tH production at the Standard Model rate can be achieved in the Higgs to diphoton decay channel alone.

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 Future e+e−Colliders at the Energy Frontier

2019 ◽  
Vol 206 ◽  
pp. 08001
Author(s):  
Tadeusz Lesiak
Keyword(s):  
Higgs Boson ◽  
Particle Physics ◽  
New Physics ◽  
Stages Of Development ◽  
Physics Program ◽  
Electron Positron ◽  
Energy Frontier

A future giant electron-positron collider, operating at the energy frontier, is a natural proposal in order to push particle physics into new regime of precise measurements, in particular in the sectors of electroweak observables and Higgs boson parameters. The four projects of such accelerators: two linear (ILC and CLIC) and two circular (FCC and CEPC) are currently in various stages of development. In view of the update of European HEP strategy for particle physics and expectations of important decisions from Japan, China and USA, the next few years will be critical as far as the decisions about the construction of such colliders are concerned. The paper concisely reviews the relevant aspects and challenges of the proposed accelerators and detectors along with the presumed schedules of construction and operation. The motivation and very attractive physics program for new e+e− colliders, spanning in particular perspectives in Higgs, electroweak, and neutrino sectors, together with expectations of searches for New Physics, will be discussed as well.

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 Higgs boson decay into a lepton pair and a photon revisited

2020 ◽  
Vol 101 (7) ◽  
Author(s):  
Aliaksei Kachanovich ◽  
Ulrich Nierste ◽  
Ivan Nišandžić
Keyword(s):  
Higgs Boson ◽  
Lepton Pair

scholarly journals Charged Higgs bosons in the NMSSM under current LHC constraints

2019 ◽  
Vol 34 (28) ◽  
pp. 1950230
Author(s):  
Zhaoxia Heng ◽  
Lin Guo ◽  
Pengqiang Sun ◽  
Wei Wei
Keyword(s):  
Higgs Boson ◽  
Parameter Space ◽  
Branching Ratio ◽  
New Physics ◽  
Direct Search ◽  
Charged Higgs Boson ◽  
Higgs Bosons ◽  
Charged Higgs ◽  
Charged Higgs Bosons ◽  
The Masses

Charged Higgs boson is a crucial prediction of new physics beyond the SM. In this work, we perform a comprehensive scan over the parameter space of NMSSM considering various experimental constraints including the direct search limits from the 13 TeV LHC, and consider the scenario that the next-to-lightest CP-even Higgs boson is SM-like. We find that the masses of charged Higgs bosons can be as light as 350 GeV, the lightest CP-even Higgs boson [Formula: see text] is predominantly singlet and can be as light as 48 GeV, and the lightest CP-odd Higgs boson [Formula: see text] is also singlet-dominated and can be as light as 82 GeV. The charged Higgs bosons mainly decay to [Formula: see text] or [Formula: see text], but the branching ratio of the exotic decays [Formula: see text] and [Formula: see text] can maximally reach 20% and 11%, respectively, which can be used to distinguish the NMSSM from MSSM. Such a heavy charged Higgs boson is inaccessible at the 13 TeV LHC with a luminosity of 36.1 fb[Formula: see text] and its detection needs higher energy and/or higher luminosity.

Scientists and Students from Hong Kong Join a Top Particle Physics Experiment

2014 ◽  
Vol 03 (02) ◽  
pp. 23-24
Author(s):  
Keyword(s):  
Hong Kong ◽  
Higgs Boson ◽  
Particle Physics ◽  
Hadron Collider ◽  
New Physics ◽  
Particle Accelerator ◽  
Atlas Collaboration ◽  
Particle Detectors ◽  
The World ◽  
Physics Experiment

A team of physicists from Hong Kong has now formally joined one of the most prestigious physics experiments in the world. Following a unanimous vote of approval today by its Collaboration Board, ATLAS has admitted the Hong Kong team as a member. The ATLAS Collaboration operates one of the largest particle detectors in the world, located at the Large Hadron Collider (LHC), the world's highest energy particle accelerator at CERN, Switzerland. In 2012, the ATLAS team — along with the CMS Collaboration — co-discovered the Higgs boson, or so-called 'God Particle'. The gigantic but sensitive and precise ATLAS detector, together with the unprecedentedly high collision energy and luminosity of the LHC, make it possible to search for fundamentally new physics, such as dark matter, hidden extra dimensions, and supersymmetry — a proposed symmetry among elementary particles. The LHC is currently undergoing an upgrade, targeting a substantial increase in beam energy and intensity in a year's time. It is widely expected that the discovery of the Higgs boson is only the beginning of an era of new breakthroughs in fundamental physics. All these exciting opportunities are now opened up to scientists and students from Hong Kong.

scholarly journals SUPERSYMMETRY PHENOMENOLOGY BEYOND THE MSSM AFTER 5/fb OF LHC DATA

2012 ◽  
Vol 27 (10) ◽  
pp. 1230010 ◽  
Author(s):  
PAOLO LODONE
Keyword(s):  
Higgs Boson ◽  
Supersymmetry Phenomenology ◽  
Cp Violation ◽  
New Physics ◽  
The Status ◽  
Recent Developments

We briefly review the status of motivated beyond-the-MSSM phenomenology in the light of the LHC searches to date. In particular, we discuss the conceptual consequences of the exclusion bounds, of the hint for a Higgs boson at about 125 GeV, and of interpreting the excess of direct CP violation in the charm sector as a signal of New Physics. We try to go into the various topics in a compact way while providing a relatively rich list of references, with particular attention to the most recent developments.

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