We present a theoretical framework that accounts for the new DJ and DsJ mesons measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional P−wave quark-antiquark states and four-quark components. The narrowest states are basically P−wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the corresponding tw...

Top-quark physics is one of the main fields of investigation at the Tevatron accelerator and, ultimately, at the LHC. We perform a phenomenological analysis of tt̄ events at hadron colliders, with a focus on observables relying on bottom-quark fragmentation in top-quark decay. In particular, we investigate the B-lepton invariant-mass distribution in the dilepton channel and give an estimate of t...

We compute the leptonic decay constants f D þ , f D s , and f K þ and the quark-mass ratios m c =m s and m s =m l in unquenched lattice QCD using the experimentally determined value of f π þ for normalization. We use the MILC highly improved staggered quark ensembles with four dynamical quark flavors—up, down, strange, and charm—and with both physical and unphysical values of the light sea-quar...

We present a lattice investigation of the heavy-light meson decay constants using Wilson light quarks and NRQCD heavy quarks, partially including the effects of dynamical sea quarks. We calculate the pseudoscalar and vector decay constants over a wide range in heavy quark mass and are able to perform a detailed analysis of heavy quark symmetry. We find consistency between the extrapolation of t...

1550-7998=20 We present the results of a nonrelativistic constituent quark model study of the semileptonic decays b ! c l l and b ! c l l (l e; ). We work on coordinate space, with baryon wave functions recently obtained from a variational approach based on heavy quark symmetry. We develop a novel expansion of the electroweak current operator, which supplemented with heavy quark effective the...

Azimuthal correlation between the (p ℓ , p X b) and (p ℓ , P t) planes in the semileptonic rest frame decay of a polarized top quark: An O(α s) effect Abstract The azimuthal correlation between the planes formed by the vectors (p ℓ , p X b) and (p ℓ , P t) in the semileptonic rest frame decay of a polarized top quark t(↑) → X b + l + + ν ℓ belongs to a class of polarization observables involvin...

A new set of measurements of the top quark mass are presented, based on the proton-proton data recorded by the CMS experiment at the LHC at ffiffi s p 1⁄4 8 TeV corresponding to a luminosity of 19.7 fb−1. The top quark mass is measured using the leptonþ jets, all-jets and dilepton decay channels, giving values of 172.35 0.16ðstatÞ 0.48ðsystÞ GeV, 172.32 0.25ðstatÞ 0.59ðsystÞ GeV, and 172.82 0.1...

The study of inclusive semileptonic decays of B mesons is analyzed from the viewpoint of probing hadron structure and strong interactions. General formulas for the differential decay rates are given in terms of the structure functions in arbitrary frame of reference, taking into account the finite charged lepton mass. These formulas can be used for structure function measurements. The behavior ...

The partial width of the decay D s → D s π going through the violation of isotopical symmetry is computed with respect to the partial width of the radiative decay D s → D s γ in the effective quark model with chiral U(3)× U(3) symmetry incorporating Heavy quark effective theory (HQET) and Chiral perturbation theory at the quark level (CHPT)q. We investigate a sensitivity of the ratio R0 = Γ(D ∗...