Space- and time-like form factors for $ω\toπγ^*$ and $K^*\to Kγ^*$ in light-front quark model

Abstract

We investigate space- and time-like form factors for $ω\toπγ^*$ and $K^*\to Kγ^*$ 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 $F_{ωπ}(q^2)$ is in good agreement with the experimental data. We also find that the space-like form factor $F_{K^{*\pm}K^{\pm}}(Q^2)$ for charged kaons encounters a zero because of the negative interference between the two currents to the quark and the antiquark.