Related papers: Light quark contributions to Higgs decays
I corrected 3 mistakes from the first version: that were an omitted Feynman integration in the function f^3_{ij}, a factor of 2 in front of log f^3_{ij} in eq.2 and an overall factor of 2 in Fig.1 c). The final result is changed…
We present new data on the mass of the light and strange quarks from SESAM/T$\chi$L. The results were obtained on lattice-volumes of $16^3\times 32$ and $24^3\times 40$ points, with the possibility to investigate finite-size effects. Since…
Three families of quarks and leptons, one Higgs to rule them all, and in the darkness bind them.
Charged Higgs scalars light enough to contribute to top quark decays are possible in various non--minimal Higgs models. We show that such a decay would be consistent with the current Tevatron data, and will remain hidden until a larger…
Two-photon decays of light scalar mesons are discussed within the quarkonium and tetraquark asignements: in both cases the decay rate of the sigma resonances turns out to be smaller than 1 keV.
In this work we investigate the weak $\Lambda_{b}\to\Lambda_c$ semi-leptonic and non-leptonic decays. The light-front quark model and diquark picture for heavy baryons are adopted to evaluate the $\Lambda_{b}\to\Lambda_c$ transition form…
The quark mass dependences of light element binding energies and nuclear scattering lengths are derived using chiral perturbation theory in combination with non-perturbative methods. In particular, we present new, improved values for the…
We analyse the fine-tuning constraints arising from absence of superpartners at LEP, without strong universality assumptions. We show that such constraints do not imply that charginos or neutralinos should have been seen at LEP, contrary to…
The leading order vacuum polarization contribution of very light millicharged fermions and scalar (spin-0) particles with charge \epsilon e and mass \mu to the Lamb shift of the hydrogen atom is shown to imply universal, i.e.…
The hypothesis of dark matter interacting with the standard model uniquely via the Higgs portal is severely challenged by experiments. However, if dark matter is a fermion, the Higgs-portal interaction implies the presence of mediators,…
We present results for QCD with 2 degenerate flavours of quark using a non-perturbatively improved action on a lattice volume of $16^3\times32$ where the bare gauge coupling and bare dynamical quark mass have been chosen to maintain a fixed…
We investigate the contributions of neutral Higgs bosons to nonleptonic transition $b \to q \bar{s} s, q=d, s$ under the supersymmetric context. Their effects to decay width and CP violation in corresponding exclusive decays are explored.…
We consider the impact of a 4th generation on Higgs to $\gamma\gamma$ and $WW,ZZ$ signals and demonstrate that the Tevatron and LHC have essentially eliminated the possibility of a 4th generation if the Higgs is SM-like and has mass below…
We study the energy correlation of charged leptons produced in the decay of a heavy Higgs particle $H\to t\bar t\to bl^+\nu_l\bar bl^-\bar{\nu}_l$ and $H\to W^+W^-\to l^+\nu_ll^-\bar{\nu}_l.$ The possible influence of $CP$--violation in the…
We show that weak scale vector-like fermions with order one couplings to the Higgs can lead to a novel mechanism for a strongly first-order electroweak phase transition (EWPhT), through their tendency to drive the Higgs quartic coupling…
We present a determination of a new class of three-loop Feynman diagrams describing heavy-to-light transitions. We apply it to find the O(alpha_s^2) corrections to the top quark decay t -> bW and to the distribution of lepton invariant mass…
In this paper, we investigate the Higgs boson decay process $H\to f\bar{f}Z\to f\bar{f}\mu^-\mu^+$, where $f$ denotes any light fermions, at the next-to-leading order (NLO) accuracy. The calculation is performed within the framework of…
We study the top quark chromomagnetic factor $\kappa_t$-dependence of the effective interaction ${\cal L}_{hgg}$ and apply the result to the case of Higgs two gluon decay rate $\Gamma_{h\to gg}$. Perturbative standard model provides…
A Dirac fermion carrying an integral weak isospin and the vanishing hypercharge is considered as its neutral component can be a promising dark matter candidate (called the minimal dark matter) whose mass is of order 100 GeV. While the…
In an extension of the standard model where baryon number and lepton number are local gauge symmetries, we analyze the effect of corrections from exotic fermions and scalars on the oblique parameters $S,\;T,\;U$. Because a light neutral…