Kaon electroweak form factors in the light-front quark model

Abstract

We investigate the form factors and decay rates for the semileptonic decays of the kaon($K_{l3})$ using the light-front quark model. The form factors $f_{\pm }(q^2)$ are calculated in $q^{+}=0$ frame and analytically continued to the time-like region, $q^2>0$. Our numerical results for the physical observables, $f_{-}/f_{+}{|}_{q^2=m_l^2}=-0.38$, ${\lambda }_{+}=0.025$(the slope of $f_{+}$ at $q^2=m_l^2$), $\Gamma (K_{e3}^0)=(7.30\pm 0.12)\times 10^6{s}^{-1}$, and $\Gamma (K_{\mu 3}^0)=(4.57\pm 0.07)\times 10^6{s}^{-1}$ are quite comparable with the experimental data and other theoretical model calculations. The non-valence contributions from $q^{+}\ne 0$ frame are also estimated.

Comments: 12 pages, 6figures, modified Sec.III and added an appendix, version to appear in Phys. Rev. D