Improvements on perturbative oscillation formulas including non-standard neutrino interactions

We use perturbation theory to obtain neutrino oscillation probabilities, including the standard mass-mixing paradigm and non-standard neutrino interactions (NSI). The perturbation is made on the standard parameters Delta m212/Delta m312 nu(e) and nu(mu) -> nu(mu). The resulting oscillation formulas are compact and present functional structure similar to the standard oscillation (SO) case. They apply to a wide range in the allowed NSI space of parameters and include the previous results from perturbative approaches as limit cases. Also, we use the compact formulas we found to explain the origin of the degeneracies in the neutrino probabilities in terms of the invariance of amplitude and phase of oscillations. Then we determine analytically the multiple sets of combinations of SO and NSI parameters that result in oscillation probabilities identical to the SO case.

Automated summary

The authors utilize perturbation theory to calculate neutrino oscillation probabilities including both standard mass-mixing and non-standard neutrino interactions (NSI). The resulting formulas are compact and apply to a wide range of parameter space. They also explain the origin of degeneracies in neutrino probabilities and analytically determine combinations of parameters that result in identical oscillation probabilities to the standard oscillation case.