Non-standard neutrino interactions in K^{+}\to\pi^{+}\nu\bar{\nu} and D^{+}\to\pi^{+}\nu\bar{\nu} decays

Abstract

We study the contributions of the non-standard neutrino interactions (NSIs) to the rare meson decays of $K^{+}\to \pi^{+} \nu\bar{\nu}$ and $D^{+}\to \pi^{+} \nu\bar\nu$. We show that both decays could provide strong constraints on the free parameters in the NSIs. We point out that the branching ratio of $D^{+}\to \pi^{+} \nu\bar\nu$ could be at the level of $10^{-8}$.