Search for short baseline $ν_e$ disappearance with the T2K near detector

Abstract

The T2K experiment has performed a search for $ν_e$ disappearance due to sterile neutrinos using $5.9 \times 10^{20}$ protons on target for a baseline of $280 m$ in a neutrino beam peaked at about $500 MeV$. A sample of ν_e CC interactions in the off-axis near detector has been selected with a purity of 63\% and an efficiency of 26\%. The p-value for the null hypothesis is 0.085 and the excluded region at 95\% CL is approximately $sin^2 2 θ_{ee} > 0.3$ for $Δm^2_{eff} > 7 eV^2 / c^4$.

8 pages, 6 figures, submitted to PRD rapid communication