VSBL Electron Neutrino Disappearance

Abstract

We consider possible indications of Very-Short-BaseLine (VSBL) electron neutrino disappearance into sterile neutrinos in MiniBooNE neutrino data and Gallium radioactive source experiments. We discuss the compatibility of such a disappearance with reactor and MiniBooNE antineutrino data. We find a tension between neutrino and antineutrino data which could be due to: 1) statistical fluctuations; 2) underestimate of systematic uncertainties; 3) exclusion of our hypothesis of VSBL nu_e disappearance; 4) a violation of CPT symmetry. Considering the first possibility, we present the results of a combined fit of all data, which indicate that P_{ee} < 1 with 97.04 CL. We consider also the possibility of CPT violation, which leads to the best-fit value A_{ee}^{CPT,bf} = -0.17 for the asymmetry of the nu_e and antinu_e survival probabilities and A_{ee}^{CPT} < 0 at 99.7 CL.