Speaker
Description
We expound in detail the degeneracy between the octant of θ23 and flavor-changing neutral-current non-standard interactions (NSI’s) in neutrino propagation, considering DUNE as a case study. In the presence of such NSI parameters involving the e − µ (εeµ) and e − τ (εeτ) flavors, the νµ → νe and νµ → νe bar appearance probabilities in long-baseline experiments acquire an additional interference term, which depends on one new dynamical CP-phase φ{eµ/eτ}. This term sums up with the well-known interference term related to the standard CP-phase δ creating a source of confusion in the determination of the octant of θ23. We show that for values of the NSI coupling (taken one at-a-time) as small as few % (relative to the Fermi coupling constant GF), and for unfavorable combinations of the two CP-phases δ and φ{eµ/eτ}, the discovery potential of the octant of θ23 gets completely lost.