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

The T2K experiment has performed a search for $ u_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 u_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 $sin^2 2 theta_{ee} > 0.3$ for $Delta m^2_{eff} > 7 eV^2 / c^4$.