scholarly journals Improved effective vector boson approximation revisited

2016 ◽  
Vol 93 (5) ◽  
Author(s):  
Werner Bernreuther ◽  
Long Chen
Keyword(s):  
Vector Boson ◽  
Boson Approximation

CONTRIBUTION OF TRANSVERSE GAUGE BOSONS TO HIGGS PRODUCTION AND THE EQUIVALENT VECTOR BOSON APPROXIMATION

1987 ◽  
Vol 02 (04) ◽  
pp. 1025-1034 ◽  
Author(s):  
R.M. GODBOLE ◽  
F. OLNESS
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Vector Boson ◽  
Higgs Production ◽  
Exact Calculation ◽  
Centre Of Mass ◽  
Gauge Bosons ◽  
Boson Approximation

It is shown that for intermediate Higgs masses, in the range 0.3– 0.6 TeV, the contribution σ T of the transversely polarized gauge bosons (V) to the process qq→qqVV→qqH , in the leading log (LL) Equivalent Vector Boson Approximation (EVBA) is comparable to the contribution σ L of the longitudinal ones. As a result the LL EVBA for σ=σ L +σ T overestimates the exact total cross-section by ~100–200 % at the q 1 q 2 centre of mass energies of interest for SSC; viz. 5–10 TeV. An improved formulation of the EVBA leads to modified vector boson densities. These densities lead to an EVBA estimate, including the transverse contributions, which agrees with the exact calculation, for m H as low as 0.3 TeV, within 20–30 % upto quark energies ~5–10 TeV .

scholarly journals Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Branching Fraction ◽  
Vector Boson ◽  
Boson Mass ◽  
Higgs Boson Mass ◽  
Vector Boson Fusion ◽  
Upper Limit ◽  
The Standard Model

Abstract A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS collaboration at the LHC, using a data set corresponding to an integrated luminosity of 130 fb−1, recorded at a center-of-mass energy of 13 TeV in 2016–2018. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for production via vector boson fusion and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, the observed (expected) 95% confidence level upper limit on the branching fraction is 3.5 (2.8)%. This is the first search for such decays in the vector boson fusion channel. Combination with a previous search for Higgs bosons produced in association with a Z boson results in an observed (expected) upper limit on the branching fraction of 2.9 (2.1)% at 95% confidence level.

scholarly journals Global analysis of the Sivers functions at NLO+NNLL in QCD

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Miguel G. Echevarria ◽  
Zhong-Bo Kang ◽  
John Terry
Keyword(s):  
Pair Production ◽  
Global Analysis ◽  
Vector Boson ◽  
Lepton Pair ◽  
Transverse Spin ◽  
Dglap Evolution ◽  
Spin Asymmetries ◽  
Lepton Pair Production ◽  
Asymmetry Data ◽  
The Impact

Abstract We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS, HERMES, and JLab, from Drell-Yan lepton pair production at COMPASS, and from W/Z boson at RHIC. This extraction is performed at next-to-leading order (NLO) and next-to-next-to leading logarithmic (NNLL) accuracy. We find excellent agreement between our extracted asymmetry and the experimental data for SIDIS and Drell-Yan lepton pair production, while tension arises when trying to describe the spin asymmetries of W/Z bosons at RHIC. We carefully assess the situation, and we study in details the impact of the RHIC data and their implications through different ways of performing the fit. In addition, we find that the quality of the description of W/Z vector boson asymmetry data could be strongly sensitive to the DGLAP evolution of Qiu-Sterman function, besides the usual TMD evolution. We present discussion on this and the implications for measurements of the transverse-spin asymmetries at the future Electron Ion Collider.

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