A new contribution to the conventional atmospheric neutrino flux

Understand

Atmospheric neutrinos are an important background to astrophysical neutrino searches, and are also of considerable interest in their own right.

• This paper points out that the contribution to conventional atmospheric $\nu_e$ of the rare semileptonic decay of $K_S$ becomes significant at high energy.
• Although the $K_S\rightarrow \pi e\nu$ branching ratio is very small, the short $K_S$ lifetime leads to a high critical energy, so that, for vertical showers, the inclusion of $K_S$ semileptonic decay increases the conventional $\nu_e$ flux by $\approx 30%$ at energies above 100 TeV.
• In this paper, we present calculations of the flux of $\nu_e$ from $K_S$.