scholarly journals Matched predictions for Higgs production via heavy-quark loops in the standard model and beyond

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Johan Alwall ◽  
Qiang Li ◽  
Fabio Maltoni
Keyword(s):  
Standard Model ◽  
Heavy Quark ◽  
Higgs Production ◽  
The Standard Model ◽  
Quark Loops

TeV Scale B – L Phenomenology at LHC

2007 ◽  
Vol 22 (31) ◽  
pp. 5889-5908 ◽  
Author(s):  
M. Abbas ◽  
W. Emam ◽  
S. Khalil ◽  
M. Shalaby
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Cross Sections ◽  
Branching Ratios ◽  
Higgs Production ◽  
Neutrino Masses ◽  
Natural Explanation ◽  
The Standard Model ◽  
The Cross

We present the phenomenology of the low scale U(1)B–L extension of the standard model and its implications at LHC. We show that this model provides a natural explanation for the presence of three right-handed neutrinos and can naturally account the observed neutrino masses and mixing. We study the decay and production of the extra gauge boson and the SM singlet scalar (heavy Higgs) predicted in this type of models. We find that the cross sections of the SM-like Higgs production are reduced by ~ 20% – 30%, while its decay branching ratios remain intact. The extra Higgs has relatively small cross sections and the branching ratios of Z′ → l+l− are of order ~ 20% compared to ~ 3% of the SM results.

B → K* ℓ+ ℓ- DECAYS WITH POLARIZED K*

2003 ◽  
Vol 18 (08) ◽  
pp. 1443-1448
Author(s):  
C. H. CHEN ◽  
C. Q. GENG
Keyword(s):  
Standard Model ◽  
Heavy Quark ◽  
B Meson ◽  
Form Factors ◽  
Decay Chain ◽  
New Physics ◽  
Effective Theory ◽  
Heavy Quark Effective Theory ◽  
B Meson Decays ◽  
The Standard Model

We study the exclusive decays of B → K* ℓ+ ℓ- within the framework of the PQCD. We obtain the form factors for the B → K* transition in the large recoil region, where the PQCD for heavy B meson decays is reliable. We find that the form factors at q2 = 0 are consistent with those from the large energy effective theory combined with the heavy quark effective theory and the experiment of B → K*γ. Via the decay chain of B → K* (Kπ) ℓ+ ℓ-, we can study many physical observables which are related to the different helicity combinations of B → K* ℓ+ ℓ-, such as the forward-backward asymmetries (FBAs). In particular, we can study the T violating effect which is small in the standard model but can be up to 10% in models with new physics.

scholarly journals Testing a Model with Additional Vector Fermions at the LEP2 Collider

1997 ◽  
Vol 12 (06) ◽  
pp. 393-401
Author(s):  
M. Heyssler ◽  
V. C. Spanos
Keyword(s):  
Standard Model ◽  
Heavy Quark ◽  
Cross Sections ◽  
Indirect Test ◽  
The Standard Model ◽  
Model Predictions ◽  
Quark Flavors

Our aim is to test a model recently presented, motivated by the reported Rb and Rc "crisis", which contains extra vector fermions. We suggest an alternative indirect test of the possible existence of new heavy quark flavors at the LEP2 collider, which turns out to give the clearest signal. We calculate [Formula: see text] cross-sections within this framework, including one-loop corrections, and find measurable differences compared to the Standard Model predictions.

scholarly journals Gluon-fusion Higgs production in the Standard Model Effective Field Theory

2017 ◽  
Vol 2017 (12) ◽  
Author(s):  
Nicolas Deutschmann ◽  
Claude Duhr ◽  
Fabio Maltoni ◽  
Eleni Vryonidou
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Gluon Fusion ◽  
Effective Field ◽  
Higgs Production ◽  
The Standard Model

scholarly journals Update on ɛK with lattice QCD inputs

2018 ◽  
Vol 175 ◽  
pp. 14015 ◽  
Author(s):  
Yong-Chull Jang ◽  
Weonjong Lee ◽  
Sunkyu Lee ◽  
Jaehoon Leem
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Lattice Qcd ◽  
Heavy Quark ◽  
Sum Rules ◽  
Qcd Sum Rules ◽  
Neutral Kaons ◽  
The Standard Model

We report updated results for ɛK, the indirect CP violation parameter in neutral kaons, which is evaluated directly from the standard model with lattice QCD inputs. We use lattice QCD inputs to fix [see formula in PDF], and mc(mc). Since Lattice 2016, the UTfit group has updated the Wolfenstein parameters in the angle-only-fit method, and the HFLAV group has also updated |Vcb|. Our results show that the evaluation of ɛK with exclusive |Vcb| (lattice QCD inputs) has 4.0σ tension with the experimental value, while that with inclusive |Vcb| (heavy quark expansion based on OPE and QCD sum rules) shows no tension.

scholarly journals Contribution of charm to rare radiative leptonic B-decays

2018 ◽  
Vol 191 ◽  
pp. 02012
Author(s):  
Anastasiia Kozachuk
Keyword(s):  
Standard Model ◽  
Charm Quark ◽  
B Decays ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Quark Loops

We revisit rare radiative leptonic decays Bd,s → γμ+μ- and Bd,s → γe+e- in the Standard Model and obtain predictions for a number of differential distributions in these decays with special emphasis on the contribution of charm-quark loops.

scholarly journals Inclusive semileptonic Λb decays in the Standard Model and beyond

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
P. Colangelo ◽  
F. De Fazio ◽  
F. Loparco
Keyword(s):  
Standard Model ◽  
Heavy Quark ◽  
Semileptonic Decays ◽  
Effective Hamiltonian ◽  
Leading Order ◽  
Left Handed ◽  
The Standard Model ◽  
Inclusive Semileptonic Decays

Abstract Inclusive semileptonic decays of beauty baryons are studied using the heavy quark expansion to $$ \mathcal{O}\left(1/{m}_b^3\right) $$ O 1 / m b 3 , at leading order in αs. The case of a polarized decaying baryon is examined, with reference to Λb. An extension of the Standard Model effective Hamiltonian inducing b → $$ U\mathrm{\ell}{\overline{\nu}}_{\mathrm{\ell}} $$ U ℓ ν ¯ ℓ transitions (U = u, c and ℓ = e, μ, τ) is considered, which comprises the full set of D=6 semileptonic operators with left-handed neutrinos. The effects of the new operators in several observables are described.

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