Related papers: Light quark contributions to Higgs decays
We present results on an analysis of the decay constants fB and fBs with two flavours of sea quark. The calculation has been carried out on 3 different bare gauge couplings and 4 sea quark masses at each gauge coupling, with m_pi/m_rho…
In this paper we investigate the next-to-leading power contribution to the $B_s \to \gamma\gamma$ and $B_s \to \gamma\ell\bar{\ell}$ decays from the strange quark mass effect with the dispersion approach which is QCD inspired and more…
A Lagrangian of electroweak interactions without Higgs is used to study the contributions of quarks and leptons to the masses of the W and the Z bosons. It is shown that the $SU(2)\times U(1)$ symmetry is broken by both fermion masses and…
Recent LHC searches have provided strong evidence for the Higgs, a boson whose gauge quantum numbers coincide with those of a SM fermion, the neutrino. This raises the mandatory question of whether Higgs and neutrino can be related by…
We analyse the interplay between the Higgs to diphoton rate and electroweak precision measurements contraints in extensions of the Standard Model with new uncolored charged fermions that do not mix with the ordinary ones. We also compute…
We propose that the leptonic cosmic ray signals seen by PAMELA and ATIC result from the annihilation or decay of dark matter particles via states of a leptonic Higgs doublet to $\tau$ leptons, linking cosmic ray signals of dark matter to…
Contributions to the energy levels in light muonic atoms and, in particular, to the Lamb shift fall into a few well-distinguished classes. The related diagrams are calculated using different approaches. In particular, there is a specific…
The results of the searches for a Higgs boson decaying to down-type fermions are presented using the proton-proton collision data collected by the ATLAS and CMS experiments at the LHC, at a centre-of-mass energy of 7 and 8 TeV. The results…
We present results for the leptonic decays of heavy-light mesons in the quenched approximation and a preliminary result for f_Ds with dynamical fermions for Nf=2. We examine the systematic effects of extrapolating the decay constants from…
We study the light-front zero-mode contribution to the tensor form factors $T_i(i=1,2,3)$ for the exclusive rare $P\to V\ell^+\ell^-$ decays using a covariant fermion field theory model in $(3+1)$ dimensions. While the zero-mode…
The decay of the Higgs boson into two photons, $h \to \gamma \gamma$, is a loop-induced process within the Standard Model, predominantly mediated by loops of $W$ bosons and top quarks. While these leading contributions are well understood,…
We compute the electroweak corrections due to the light fermions to the production cross section $\sigma(g g \to H)$ and to the partial decay widths $\Gamma (H \to \gamma \gamma)$ and $\Gamma (H \to g g)$. We present analytic results for…
A simple thought experiment suggests that, contrary to assertions in an earlier Letter, constancy across materials of the ratio of active to passive gravitational mass does not rule out that electrons (and other leptons) could have active…
We propose a multiplicative formulation of the Higgs Lagrangian, derived from the inverse problem in the calculus of variations, as an alternative framework to investigate the fermion mass hierarchy. In this setup, fermion masses emerge as…
We study the exclusive decay of $J/\Psi$ into a lepton pair combined with light hadrons in the kinematic region, specified by that the total energy of the light hadrons is much smaller than $m_c$, the mass of the $c$-quark. In this region,…
We derive the low-energy electroweak effective lagrangian for the case of additional heavy, unmixed, sequential fermions. Present data still allow for the presence of a new quark and/or lepton doublet with masses greater than $M_Z/2$,…
We compute the fermionic radiative contributions to the decay $H^+ \to W^{+(*)} A^0$ in the framework of models with two Higgs doublets (2HDM), for the case of an on-shell and off-shell W. We show that, in the majority of the cases, current…
The effects of spectator light quark in decays of heavy mesons are considered, which vanish in the limit of factorization of matrix elements of four-quark operators over the mesons. These effects include the difference of the total widths…
We report contributions to the nucleon spin and momentum from light quarks calculated using dynamical domain wall fermions with pion masses down to 300 MeV and fine lattice spacing a=0.084 fm. Albeit without disconnected diagrams, we…
The Higgs-mass dependence of the two-loop contributions to muon decay is analyzed at the two-loop level. Exact results are given for the Higgs-dependent two-loop corrections associated with the fermions, i.e. no expansion in the top-quark…