New constraints on muon-neutrino to electron-neutrino transitions in MINOS

This paper reports results from a search for ν_μ→νₑ transitions by the MINOS experiment based on a 7×10²⁰ protons-on-target exposure. Our observation of 54 candidate νₑ events in the far detector with a background of 49.1±7.0(stat)±2.7(syst) events predicted by the measurements in the near detector requires 2sin²(2θ₁₃)sin²θ₂₃<0.12(0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at δCP=0. The experiment sets the tightest limits to date on the value of θ₁₃ for nearly all values of δCP for the normal neutrino mass hierarchy and maximal sin²(2θ₂₃).