CP-Invariance Violation at Short-Baseline Experiments in 3+1 Neutrino Scenarios

Understand

New neutrino degrees of freedom allow for more sources of CP-invariance violation (CPV).

• We explore the requirements for accessing CP-odd mixing parameters in the so-called 3+1 scenario, where one assumes the existence of one extra, mostly sterile neutrino degree of freedom, heavier than the other three mass eigenstates.
• As a first step, we concentrate on the nu_e to nu_mu appearance channel in a hypothetical, upgraded version of the nuSTORM proposal.
• We establish that the optimal baseline for CPV studies depends strongly on the value of Delta m^2_14 -- the new mass-squared difference -- and that the ability to observe CPV depends significantly on whether the experiment is performed at the optimal baseline.