Analysis of hadronic coupling constants $G_{B_c^{\ast }{B}_c{\rm Y}}$, $G_{B_c^{\ast }{B}_{c}J/\psi }$, $G_{B_c{B}_c{\rm Y}}$ and $G_{B_c{B}_{c}J/\psi }$ with QCD sum rules

Abstract

In this article, we study momentum dependence of the hadronic coupling constants $G_{B_c^{\ast }{B}_c{\rm Y}}$, $G_{B_c^{\ast }{B}_{c}J/\psi }$, $G_{B_c{B}_c{\rm Y}}$ and $G_{B_c{B}_{c}J/\psi }$ with the off-shell ${\rm Y}$ and $J/\psi$ using the three-point QCD sum rules. Then we fit the hadronic coupling constants into analytical functions and extrapolate them into deep time-like regions to obtain the on-shell values $G_{B_c^{\ast }{B}_c{\rm Y}}(q^2=M_{{\rm Y}}^2)$, $G_{B_c^{\ast }{B}_{c}J/\psi }(q^2=M_{J/\psi }^2)$, $G_{B_c{B}_c{\rm Y}}(q^2=M_{{\rm Y}}^2)$ and $G_{B_c{B}_{c}J/\psi }(q^2=M_{J/\psi }^2)$ for the first time. Those hadronic coupling constants can be taken as basic input parameters in phenomenological analysis.

Comments: 18 pages, 17 figures