2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191325Within 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 $K^+ \to γ$ transition. We use these form factors to study the decay of $K^+ \to e^+ ν_{e}γ$, which is dominated by the structure dependent contribution. We show the differential decay branching ratio as a function of $x=2E_γ/m_K$, where $E_γ$ ($m_K$) 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 $K^+ \to e^+ ν_{e}γ$ is $1.54 (1.44)\times 10^{-5}$ and $1.57 (1.47)\times 10^{-5}$ in the LFQM and ChPT, respectively.15 pages, 4 figures, final version to be published in PRDHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext