相关论文: Study of $B_s\to \phi \ell^+ \ell^-$ decays in the…

Precise theoretical predictions derived from the Standard Model are a key ingredient in searches for new physics in the flavor sector. The large mass and long lifetime of the $b$ quark make processes involving $b$ quarks of particular…

We present an exploratory lattice study of $B\to\pi$ semileptonic decay form factors using the nonrelativistic lattice QCD for heavy quark with Wilson light quark on a $16^3 \times 32$ quenched lattice at $\beta=5.8$. The matrix elements…

The form factors of the semileptonic $B_{q}\to D_{q}(J^{P}=0^{-})\ell\nu$ with $q=s, u, d$ transitions are calculated in the framework of three point QCD sum rules. Using the $q^2$ dependencies of the relevant form factors, the total decay…

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…

We investigate the $B_{d,s}^0 \to f_1 f_1$ decays in the framework of perturbative QCD(PQCD) approach with a referenced value $\phi_{f_1} \sim 24^\circ$. Here, $f_1$ denotes the axial-vector mesons $f_1(1285)$ and $f_1(1420)$ with mixing…

We present a lattice-QCD determination of the $\Lambda \to p$ vector and axial-vector form factors, providing theoretical input for studies of the semileptonic decay $\Lambda \to p\ell\bar{\nu}_\ell$. The calculation is carried out on a…

The form factors relevant to $B_{q}\to D^{\ast}_{q}(J^{P}=1^{-}) ell\nu$ $(q=s, d, u)$ decays are calculated in the framework of the three point QCD sum rules approach. The heavy quark effective theory prediction of the form factors as well…

In 2017, LHCb collaboration reported their first observation of the rare decays $B_s \to \phi (f_0(980)$ $/f_2(1270) \to ) \pi^+\pi^-$ and the evidence of $B^0 \to \phi(f_0(980)/f_2(1270)\to)\pi^+\pi^-$. Motivated by this, we study these…

We present results of the first lattice QCD calculations of $B_c \to B_s$ and $B_c \to B_d$ weak matrix elements. Form factors across the entire physical $q^2$ range are then extracted and extrapolated to the physical-continuum limit before…

By employing the perturbative QCD (PQCD) factorization approach, we made a systematic investigation for the CP-averaged branching ratios and the CP-violating asymmetries of the thirteen $\bar{B}^0_s \to PP $ decays ( here $P=(\pi,K, \eta,…

The semileptonic process, B --> \pi l \nu, is studied via full QCD Lattice simulations. We use unquenched gauge configurations generated by the MILC collaboration. These include the effect of vacuum polarization from three quark flavors:…

We calculate the branching ratios and CP asymmetries of the $B\to \phi K$ decays using perturbative QCD approach, which includes $k_T$ and threshold resummations. Our results of branching ratios are consistent with the experimental data and…

We analyze the semileptonic $ B_{s} \rightarrow D_{s2}^{*}(2573)\ell\bar{\nu }_{\ell}$ transition, where $\ell=\tau,~\mu$ or $e$, within the standard model. We apply the QCD sum rule approach to calculate the transition form factors…

We present the first lattice QCD determination of the $\Lambda \to N$ vector and axial-vector form factors, which are essential inputs for studying the semileptonic decay $\Lambda \to p \ell \bar{\nu}_\ell$. This channel provides a clean,…

Semileptonic $B_s \to K \ell \nu$ decays provide an alternative $b$-decay channel to determine the CKM matrix element $|V_{ub}|$, and to obtain a $R$-ratio to investigate lepton-flavor-universality violations. Results for the CKM matrix…

Based on the helicity method, formulae for the semileptonic transition of $\Lambda_b^0 \to \Lambda_c^+ \ell^- \bar \nu_\ell$ including lepton mass effects are derived. In order to calculate the form factors of the $\Lambda_b$ baryon…

We present updates for our nonperturbative lattice QCD calculations to determine semileptonic form factors for exclusive $B\to \pi\ell\nu$, $B\to D \ell\nu$, $B_s\to K\ell \nu$, and $B_s\to D_s\ell\nu$ decays. Our calculation is based on…

We determine, by means of lattice QCD calculations, the local form factors describing the $B_{s}\to \mu^{+}\mu^{-}\gamma$ decay. For this analysis we make use of the gauge configurations produced by the ETM Collaboration with $N_{f}=2+1+1$…

We update the lattice calculation of the $B\to\pi$ semileptonic form factors, which have important applications to the CKM matrix element $|V_{ub}|$ and the $B\to\pi\ell^+\ell^-$ rare decay. We use MILC asqtad ensembles with $N_f=2+1$ sea…

By employing the perturbative QCD (PQCD) factorization approach, we calculated the branching ratios, CP-violating asymmetries, the longitudinal and transverse polarization fractions and other physical observables of the thirteen charmless…