相关论文: Neutral B-meson mixing from full lattice QCD at th…

We calculate the kaon $B$-parameter in quenched lattice QCD at $\beta=6.0$ using Wilson fermions at $\kappa=0.154$ and $0.155$. We use two kinds of non-local (``smeared'') sources for quark propagators to calculate the matrix elements…

The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the \Delta s=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables…

We compute on the lattice the ``bag'' parameters of the five (Delta B = 2) operators of the supersymmetric basis, by combining their values determined in full QCD and in the static limit of HQET. The extrapolation of the QCD results from…

We compute several matrix elements of dimension-six four-fermion operators and extract their B-parameters. The calculations have been performed with the tree-level Clover action at $\beta = 6.0$. The renormalization constants and mixing…

We calculate the B-parameters for operators arising in theories of new physics beyond the standard model (BSM) using HYP-smeared improved staggered fermions on the MILC asqtad lattices with N_f = 2+1 flavors. We use three different lattice…

We present the preliminary result of the calculation of $B_B$ parameter using lattice NRQCD. The calculation is performed on a $16^3 \times 48$ quenched lattice at $\beta=5.9$ with clover light quark. The use of lattice NRQCD enables us to…

We present a high statistics, quenched lattice calculation of the B-parameters $B_{B_d}$ and $B_{B_s}$, computed at lowest order in the HQET. The results were obtained using a sample of 600 quenched gauge field configurations, generated by…

The more precise extraction for the CKM matrix element |V_{cb}| in the heavy quark effective field theory (HQEFT) of QCD is studied from both exclusive and inclusive semileptonic B decays. The values of relevant nonperturbative parameters…

We present results for the $SU(3)$ breaking ratios of decay constants $f_{D_s}/f_D$ and $f_{B_s}/f_B$ and - for the first time with physical pion masses - the ratio of bag parameters $B_{B_s}/B_{B_d}$, as well as the ratio $\xi$, forming…

We present a calculation of the B and D meson decay constants in lattice QCD with two (Nf=2) flavours of light dynamical quarks, using an O(a)-improved Wilson action for both light and heavy quarks and a renormalization-group improved gauge…

We present precise lattice computations for the b-quark mass, the quark mass ratios mb/mc and mb/ms as well as the leptonic B-decay constants. We employ gauge configurations with four dynamical quark flavors, up/down, strange and charm, at…

We fit the ${\cal CKM}$-matrix to all recent data with the following free parameters: three mixing angles, the CP-violating angle $\delta$ in the Maiani parametrisation, the top quark mass $m_t$, and the product $f_B{\cal B}_{\B}^{1/2}$,…

We present an update of the D meson decay constant f_D using the Highly Improved Staggered Quark (HISQ) action for valence charm and light quarks on MILC N_f = 2+1 lattices. The new determination incorporates HPQCD's improved scale r_1^{N_f…

We present an analysis of exclusive charmless semileptonic B-meson decays based on 377 million BBbar pairs recorded with the BABAR detector at the Upsilon(4S) resonance. We select four event samples corresponding to the decay modes B0 -->…

$B_s - \bar B_s$ mixing has been measured recently by D0 and CDF. The range predicted in the standard model is consistent with data. However, the standard model central values for $\Delta M_{B_s}$ and also $\Delta M_ {B_d}$ are away from…

We present a progress report on new calculations of B and B_s meson decay constants employing NRQCD heavy and HISQ light valence quarks and using MILC N_f = 2+1 AsqTad lattices. Bare quark masses have been retuned in accord with HPQCD's new…

In this work, we derive the form factors and compute the branching fractions for the semitauonic decay modes, $B \to D^{(*)}\,\tau\,\nu_{\tau}$, $B_s \to D_s^{(*)}\,\tau\,\nu_{\tau}$, $B_c \to \eta_c\,(J/\psi)\,\tau\,\nu_{\tau}$, and $B_c…

The use of improved staggered actions (HYP, Asqtad) has been proved to reduce the scaling corrections that affected previous calculations of B_K with unimproved (standard) staggered fermions in the quenched approximation. This improved…

The ratio of the CKM quark-mixing matrix elements |Vub|/|Vcb| has been measured using B hadron semileptonic decays. The analysis uses the reconstructed mass M_X of the secondary hadronic system produced in association with an identified…

Within $Z^\prime$ models, neutral meson mixing severely constrains beyond the Standard Model (SM) effects in flavour changing neutral current (FCNC) processes. However, in certain regions of the $Z^\prime$ parameter space, the contributions…