Prospects of light sterile neutrino oscillation and CP violation searches at the Fermilab Short Baseline Neutrino Facility.

摘要

We investigate the ability of the short baseline neutrino (SBN) experimental program at Fermilabudto test the globally-allowed (3 þ N) sterile neutrino oscillation parameter space. We explicitly considerudthe globally-allowed parameter space for the (3 þ 1), (3 þ 2), and (3 þ 3) sterile neutrino oscillationudscenarios. We find that SBN can probe with 5σ sensitivity more than 85%, 95% and 55% ofudthe parameter space currently allowed at 99% confidence level for the (3 þ 1), (3 þ 2) and (3 þ 3)udscenarios, respectively, with the (3 þ N) allowed space used in these studies closely resembling that ofudprevious studies [J. M. Conrad, C. M. Ignarra, G. Karagiorgi, M. H. Shaevitz, and J. Spitz, Adv. HighudEnergy Phys. 2013, 1 (2013).], calculated using the same methodology. In the case of the (3 þ 2) andud(3 þ 3) scenarios, CP-violating phases appear in the oscillation probability terms, leading to observableuddifferences in the appearance probabilities of neutrinos and antineutrinos. We explore SBN’s sensitivity toudthose phases for the (3 þ 2) scenario through the currently planned neutrino beam running, andudinvestigate potential improvements through additional antineutrino beam running. We show that, ifudantineutrino exposure is considered, for maximal values of the (3 þ 2) CP-violating phase ϕ54, SBNudcould be the first experiment to directly observe ∼2σ hints of CP violation associated with an extendedudlepton sector.