scholarly journals Two-loop mixed QCD-EW corrections to gg → Hg

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Marco Bonetti ◽  
Erik Panzer ◽  
Vladimir A. Smirnov ◽  
Lorenzo Tancredi
Keyword(s):  
Higgs Boson ◽  
Differential Equations ◽  
Helicity Amplitude ◽  
Numerical Evaluation ◽  
Gluon Fusion ◽  
Physical Region ◽  
Multiple Polylogarithms ◽  
Helicity Amplitudes ◽  
Weight Drop

Abstract We compute the two-loop mixed QCD-Electroweak (QCD-EW) corrections to the production of a Higgs boson and a gluon in gluon fusion through a loop of light quarks. The relevant four-point functions with internal massive propagators are expressed as multiple polylogarithms with algebraic arguments. We perform the calculation by integration over Feynman parameters and, independently, by the method of differential equations. We compute the two independent helicity amplitudes for the process and we find that they are both finite. Moreover, we observe a weight drop when all gluons have the same helicity. We also provide a simplified expression for the all-plus helicity amplitude, which is optimised for fast and reliable numerical evaluation in the physical region.

scholarly journals Contribution of third generation quarks to two-loop helicity amplitudes for W boson pair production in gluon fusion

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Christian Brønnum-Hansen ◽  
Chen-Yu Wang
Keyword(s):  
Phase Space ◽  
Differential Equations ◽  
Pair Production ◽  
W Boson ◽  
Gluon Fusion ◽  
Third Generation ◽  
Boson Pair ◽  
Boson Pair Production ◽  
Helicity Amplitudes ◽  
Loop Amplitude

Abstract We compute the contribution of third generation quarks (t, b) to the two-loop amplitude for on-shell W boson pair production in gluon fusion gg → WW. We present plots for the amplitude across partonic phase space as well as reference values for two kinematic points. The master integrals are efficiently evaluated by numerically solving a system of ordinary differential equations.

scholarly journals Boosting invisible Higgs boson searches by tagging a gluon jet for the gluon fusion process

2020 ◽  
Vol 102 (11) ◽  
Author(s):  
Won Sang Cho ◽  
Hyung Do Kim ◽  
Dongsub Lee
Keyword(s):  
Higgs Boson ◽  
Gluon Fusion ◽  
Fusion Process

scholarly journals ZH production in gluon fusion: two-loop amplitudes with full top quark mass dependence

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Long Chen ◽  
Gudrun Heinrich ◽  
Stephen P. Jones ◽  
Matthias Kerner ◽  
Jonas Klappert ◽  
...  
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Mass Dependence ◽  
Finite Part ◽  
Top Quark Mass ◽  
Helicity Amplitudes ◽  
Quark Mass Dependence ◽  
Loop Amplitudes

Abstract We present results for the two-loop helicity amplitudes entering the NLO QCD corrections to the production of a Higgs boson in association with a Z -boson in gluon fusion. The two-loop integrals, involving massive top quarks, are calculated numerically. Results for the interference of the finite part of the two-loop amplitudes with the Born amplitude are shown as a function of the two kinematic invariants on which the amplitudes depend.

scholarly journals Higgs boson production via gluon fusion: Squark loops at NLO QCD

2008 ◽  
Vol 790 (1-2) ◽  
pp. 1-27 ◽  
Author(s):  
Margarete Mühlleitner ◽  
Michael Spira
Keyword(s):  
Higgs Boson ◽  
Gluon Fusion ◽  
Boson Production ◽  
Higgs Boson Production

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 The diagrammatic coaction beyond one loop

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Samuel Abreu ◽  
Ruth Britto ◽  
Claude Duhr ◽  
Einan Gardi ◽  
James Matthew
Keyword(s):  
Differential Equations ◽  
Hypergeometric Functions ◽  
Differential Forms ◽  
Feynman Graph ◽  
Loop Order ◽  
Feynman Integrals ◽  
Mathematical Properties ◽  
Multiple Polylogarithms ◽  
Complete Set ◽  
General Tool

Abstract The diagrammatic coaction maps any given Feynman graph into pairs of graphs and cut graphs such that, conjecturally, when these graphs are replaced by the corresponding Feynman integrals one obtains a coaction on the respective functions. The coaction on the functions is constructed by pairing a basis of differential forms, corresponding to master integrals, with a basis of integration contours, corresponding to independent cut integrals. At one loop, a general diagrammatic coaction was established using dimensional regularisation, which may be realised in terms of a global coaction on hypergeometric functions, or equivalently, order by order in the ϵ expansion, via a local coaction on multiple polylogarithms. The present paper takes the first steps in generalising the diagrammatic coaction beyond one loop. We first establish general properties that govern the diagrammatic coaction at any loop order. We then focus on examples of two-loop topologies for which all integrals expand into polylogarithms. In each case we determine bases of master integrals and cuts in terms of hypergeometric functions, and then use the global coaction to establish the diagrammatic coaction of all master integrals in the topology. The diagrammatic coaction encodes the complete set of discontinuities of Feynman integrals, as well as the differential equations they satisfy, providing a general tool to understand their physical and mathematical properties.

On Higgs Boson Production via Gluon Fusion

2018 ◽  
Vol 73 (1) ◽  
pp. 57-60
Author(s):  
A. V. Borisov ◽  
E. A. Stepanova
Keyword(s):  
Higgs Boson ◽  
Gluon Fusion ◽  
Boson Production ◽  
Higgs Boson Production

scholarly journals TWO COMPOSITE HIGGS DOUBLETS: IS IT THE LOW ENERGY LIMIT OF A NATURAL STRONG ELECTROWEAK SYMMETRY BREAKING SECTOR?

2010 ◽  
Vol 25 (06) ◽  
pp. 423-429 ◽  
Author(s):  
ALFONSO R. ZERWEKH
Keyword(s):  
Higgs Boson ◽  
Symmetry Breaking ◽  
Top Quark ◽  
Gluon Fusion ◽  
Electroweak Symmetry Breaking ◽  
Electroweak Symmetry ◽  
Associated Production ◽  
Composite Higgs ◽  
Main Production ◽  
Model Scheme

In this paper, we propose an effective model scheme that describes the electroweak symmetry breaking sector by means of composite Higgs-like scalars, following the ideas of Minimal Walking Technicolor (MWT). We argue that, because of the general failure of Extended Technicolor (ETC) to explain the mass of the top quark, it is necessary to introduce two composite Higgs bosons: one of them originated by a MWT–ETC sector and the other produced by a Topcolor sector. We focus on the phenomenological differences between the light composite Higgs present in our model and the fundamental Higgs boson predicted by the Standard Model and their production at the LHC. We show that in this scheme the main production channel of the lighter Higgs boson is the associated production with a gauge boson and WW fusion but not the gluon–gluon fusion channel which is substantially suppressed.

scholarly journals Search for a light pseudoscalar Higgs boson in the boosted μμττ final state in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Branching Fraction ◽  
Vector Boson ◽  
Mass Difference ◽  
Standard Technique ◽  
Gluon Fusion ◽  
Large Mass ◽  
Proton Collision ◽  
Final State ◽  
Proton Proton

Abstract A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1, collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H → aa → μμττ, and considers pseudoscalar masses in the range 3.6 < ma< 21 GeV. Because of the large mass difference between the H and the a bosons and the small masses of the a boson decay products, both the μμ and the ττ pairs have high Lorentz boost and are collimated. The ττ reconstruction efficiency is increased by modifying the standard technique for hadronic τ lepton decay reconstruction to account for a nearby muon. No significant signal is observed. Model-independent limits are set at 95% confidence level, as a function of ma, on the branching fraction (ℬ) for H → aa → μμττ, down to 1.5 (2.0) × 10−4 for mH = 125 (300) GeV. Model-dependent limits on ℬ(H → aa) are set within the context of two Higgs doublets plus singlet models, with the most stringent results obtained for Type-III models. These results extend current LHC searches for heavier a bosons that decay to resolved lepton pairs and provide the first such bounds for an H boson with a mass above 125 GeV.

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