Space- and time-like form factors for $\omega \to \pi {\gamma }^{\ast }$ and $K^{\ast }\to K{\gamma }^{\ast }$ in light-front quark model

Abstract

We investigate space- and time-like form factors for $\omega \to \pi {\gamma }^{\ast }$ and $K^{\ast }\to K{\gamma }^{\ast }$ decays using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent space-like form factors are obtained in the $q^{+}=0$ frame and then analytically continued to the time-like region. Our prediction for the time-like form factor $F_{\omega \pi }(q^2)$ is in good agreement with the experimental data. We also find that the space-like form factor $F_{K^{\ast \pm }{K}^{\pm }}(Q^2)$ for charged kaons encounters a zero because of the negative interference between the two currents to the quark and the antiquark.

Comments: 4pages, 4figures