Analysis of K+-> e(+)nu(e)gamma in light-front quark model and chiral perturbation theory of order p(6)

Within the frameworks of the light-front quark model (LFQM) and chiral perturbation theory (ChPT) of O(p(6)), we reevaluate the form factors of the K+->gamma transition. We use these form factors to study the decay of K+-> e(+)nu(e)gamma, which is dominated by the structure-dependent contribution. We show the differential decay branching ratio as a function of x=2E(gamma)/m(K), where E-gamma(m(K)) is the photon energy (kaon mass). Explicitly, we find that, in the standard model with the cut of x=0.01 (0.1), the decay branching ratio of K+-> e(+)nu(e)gamma is 1.54(1.44)x10(-5) and 1.57(1.47)x10(-5) in the LFQM and ChPT, respectively.