Decay constants and radiative decays of heavy mesons in light-front quark model

Abstract

We investigate the magnetic dipole decays $V\ensuremath{\rightarrow}P\ensuremath{\gamma}$ of various heavy-flavored mesons such as $(D,{D}^{*},{D}_{s},{D}_{s}^{*},{\ensuremath{\eta}}_{c},J/\ensuremath{\psi})$ and $(B,{B}^{*},{B}_{s},{B}_{s}^{*},{\ensuremath{\eta}}_{b},\ensuremath{\Upsilon})$ using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors ${F}_{VP}({q}^{2})$ for $V\ensuremath{\rightarrow}P{\ensuremath{\gamma}}^{*}$ decays are obtained in the ${q}^{+}=0$ frame and then analytically continued to the timelike region by changing ${\mathbf{q}}_{\ensuremath{\perp}}$ to $i{\mathbf{q}}_{\ensuremath{\perp}}$ in the form factors. The coupling constant ${g}_{VP\ensuremath{\gamma}}$ for real photon case is then obtained in the limit as ${q}^{2}\ensuremath{\rightarrow}0$, i.e. ${g}_{VP\ensuremath{\gamma}}={F}_{VP}({q}^{2}=0)$. The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations.