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

Abstract

We investigate the magnetic dipole decays $V\to Pγ$ of various heavy-flavored mesons such as $(D,D^*,D_s,D^{*}_s,η_c, J/ψ)$ and $(B,B^*,B_s,B^*_s,η_b,Υ)$ 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 $V\to Pγ^*$ decays are obtained in the $q^+=0$ frame and then analytically continued to the timelike region by changing ${\bf q}_\perp$ to $i{\bf q}_\perp$ in the form factors. The coupling constant $g_{VPγ}$ for real photon case is then obtained in the limit as $q^2\to 0$, i.e. $g_{VPγ}=F_{VP}(q^2=0)$. 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.