相关论文: The $B_c$ mass up to order $\alpha_s^4$

In the wake of measurements on $B_c^+ \to J/\psi K^+$, $B_c^+ \to J/\psi \pi^+\pi^-\pi^+$, and $B_c^+ \to J/\psi K^+ K^-\pi^+$ at Large Hadron Collider experiments, we propose to study the decays $B_c^+ \to J/\psi M^+$ comprehensively, with…

We propose a novel method to calculate the meson mass in the framework of Dyson-Schwinger equation and Bethe-Salpeter equation, once their dominant interactions are identified. The method is based on the perturbation theory of matrix, which…

We compute the two-loop term in the perturbation series for the quark-mass in the lattice Heavy Quark Effective Theory. This is an ingredient in the matching factor required to obtain the $b$-quark mass from lattice simulations of the HQET.…

The B-meson distribution amplitude is calculated using QCD sum rules. In particular we obtain an estimate for the integral relevant to exclusive B-decays \lambda_B = 460 \pm 110 MeV at the scale 1 GeV. A simple QCD-motivated parametrization…

Motivated by recent interest in soft $J/\Psi$ production in B decays, we investigate ${B}^0 \to J/\Psi D^{(\star)}$ and $\eta_c D^{(\star)}$ decays in perturbative QCD. We find that, within that framework, these decays are calculable since…

Theoretical predictions for inclusive semileptonic B decay rates are rewritten in terms of the Upsilon(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. This method gives theoretically consistent and…

In this work, we study higher $B_c$ mesons to the $L=S$, $P$, $D$, $F$, $G$ multiplets using the Cornell potential model, which takes account of the screening effect. The calculated mass spectra of $B_c$ states are in reasonable agreement…

Motivated by systematic observations of $ B_c $ decays at LHCb, we analyze $B_c^+ \to J/\psi (A, T)$ decays (where $A$ denotes axial-vector mesons $a_1(1260)^+$, $b_1(1235)^+$, and $T$ denotes tensor mesons $a_2(1320)^+$, $K_2^*(1430)^+$)…

We investigate the mass and decay constant of the heavy-heavy pseudoscalar, $B_c$, $\eta_c$ and $\eta_b$ mesons in the framework of finite temperature QCD sum rules. The annihilation and scattering parts of spectral density are calculated…

The $B_{u}$ ${\to}$ ${\psi}M$ decays are studied with the perturbative QCD approach, where the psion ${\psi}$ $=$ ${\psi}(2S)$, ${\psi}(3770)$, ${\psi}(4040)$ and ${\psi}(4160)$, and the light meson $M$ $=$ ${\pi}$, $K$, ${\rho}$ and…

Two body $B$ meson decays involving the radially excited meson $\psi(2S)/\eta_c(2S)$ in the final states are studied by using the perturbative QCD (pQCD) approach. We find that: (a) The branching ratios for the decays involving $K$ meson…

Inspired by the recent LHCb measurements and forthcoming great potential on $B_{c}$ meson, we study the exclusive $B_{c}$ ${\to}$ $B_{q}P$, $B_{q}V$ decays with the perturbative QCD approach, where $q$ $=$ $u$, $d$, $s$; $P$ and $V$ denote…

We present a precise lattice QCD determination of the b-quark mass, of the B and Bs decay constants and first results for the B-meson bag parameters. For our computation we employ the so-called ratio method and our results benefit from the…

In the present work, we use optical theorem to calculate the next-to-leading order corrections to the QCD spectral densities directly in the QCD sum rules for the pseudoscalar and scalar $B_c$ mesons. We take the experimental data as guides…

We study two-body hadronic $B_s\to PT$ decays, with $P (T)$ being a light pseudoscalar (tensor) meson, in the perturbative QCD approach. The CP-averaged branching ratios and the direct CP asymmetries of the $\Delta S=0$ modes are predicted,…

Comparing the result of inserting a complete set of physical states in a time ordered product of $b$ decay currents with the operator product expansion gives a class of zero recoil sum rules. They sum over physical states with excitation…

Using recently evaluated contributions (including a novel one calculated here), we present updated values for the pole mass and $\bar{MS}$ mass of the $b$ quark: $m_b=5022\pm58$ MeV, for the pole mass, and $\bar{m}_b(\bar{m}_b)=4286\pm36$…

We study finite size effects in superconducting metallic grains and determine the BCS order parameter and the low energy excitation spectrum in terms of size, and shape of the grain. Our approach combines the BCS self-consistency condition,…

Within the framework of the perturbative QCD approach, we calculate the time-like $B_cB_c(B_c^*)$ form factors $F(Q^2)$ and $A_2(Q^2)$. We include relativistic corrections and QCD corrections, either of which can give about $20\%$…

We determine the bottom quark mass $\hat{m}_b$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD to ${\cal O} (\hat\alpha_s^3)$. Our approach is based on the mutual consistency across a set of…