نتایج جستجو برای: quark decay
تعداد نتایج: 99408 فیلتر نتایج به سال:
Moments of the renormalized B-meson shape function provide a natural way to define short-distance, running heavy-quark parameters such as the b-quark mass and kinetic energy. These parameters are particularly well suited for studies of inclusive decay distributions. The definitions of mb and μ 2 π in this “shape-function scheme” are derived to two-loop order. Using previous determinations of he...
Standard Model fits are performed on the most recent leptonic and b quark Z decay data from LEP and SLD, and FERMILAB data on top quark production, to obtain m t and m H. Poor fits are obtained, with confidence levels ≃ 2%. Removing the b quark data improves markedly the quality of the fits and reduces the 95% CL upper limit on m H from 169 GeV to 110 GeV.
It is hoped that the accuracy of a variety of lattice calculations will be improved by perturbatively eliminating effects proportional to the lattice spacing. In this paper, we apply this improvement program to the heavy quark effective theory currents which cause a heavy quark to decay to a light quark, and renormalize the resulting operators to order αS. We find a small decrease in the amount...
Single top quark production at hadron colliders allows a direct measurement of the top quark charged current coupling. We present the complete tree-level helicity amplitudes for four processes involving the production and semileptonic decay of a single top quark: W -gluon fusion, flavor excitation, s-channel production and W associated production. For the first three processes we study the qual...
In this paper, we evaluate the expectation values of four-quark operators for the inclusive beauty decays from the differences in the inclusive total decay rates, assuming that the heavy quark expansion converges at O(1/m). The obtained expectation values values yeilds the ratio τ(Λb)/τ(B) close to the experimental value. We further point out that the quark-hadron duality violation would be rat...
We review recent results for the chiral behavior of meson masses and decay constants and the determination of the light quark masses by the RBC and UKQCD collaborations. We find that one-loop SU(2) chiral perturbation theory represents the behavior of our lattice data better than one-loop SU(3) chiral perturbation theory in both the pion and kaon sectors. The simulations have been performed usi...
The mass of the top quark is measured in a data set corresponding to 4.6 fb −1 of proton–proton collisions with centre-of-mass energy √ s = 7 TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top–antitop quark pairs with at least six jets in the final state are selected. The substantial background from mul-tijet production is modelled with data-driven met...
We review recent results for the chiral behavior of meson masses and decay constants and the determination of the light quark masses by the RBC and UKQCD collaborations. We find that one-loop SU(2) chiral perturbation theory represents the behavior of our lattice data better than one-loop SU(3) chiral perturbation theory in both the pion and kaon sectors. The simulations have been performed usi...
Twelve years after the discovery of the Top quark, the CDF detector has collected large samples of tt̄ events with integrated luminosities up to 1-1.7 fb, where we are able to probe our knowledge of the Standard Model Top quark. This article will foccuss on those analysis results dedicated to find new physics in the Top quark production: measurement of relative fractions of Top pair production m...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید