Nuclear Seminar - Amina Khatun (2.6.2021)
Wednesday 2.6.2021 at 14:00, online
By: Jaroslav Staníček
Dr. Amina Khatun, PhD.:
A New Approach to Probe NSI in Atmospheric Neutrino Experiments using Dip and Valley
The discovery of neutrino oscillation proves that neutrinos have nonzero mass, and they mix with each other. This has been the first direct experimental evidence of physics beyond the Standard Model. Since then, the data of neutrino experiments has been widely studied for the searches of interactions that are not allowed in the Standard Model which we call here as Non-Standard Interaction (NSI). In this talk, I will discuss a new approach to explore the neutral-current NSI with oscillation dip and valley in atmospheric neutrino experiments using a detector like ICAL that can identify the muon charge. The flavor-changing NSI parameter in 2-3 block of matter potential matrix has the maximum impact on the muon survival probability in these experiments. It is seen that the nonzero value of this NSI shifts the oscillation dip locations in L/E distributions of the up/down event ratios of reconstructed muon and antimuon in opposite directions. A new variable representing the difference of dip locations in muon and antimuon is sensitive to the magnitude as well as the sign of NSI, and is independent of the value of atmospheric mass-squared difference. The oscillation valley in the [energy, cosine of zenith angle] plane of the reconstructed muon observables bends in the presence of NSI, its curvature having opposite signs for muon and antimuon. The identification of NSI with this curvature is feasible for detectors like ICAL having excellent muon energy and direction resolutions. Using these proposed oscillation dip and valley measurements, the achievable precision on NSI at 90% C.L. is about 2% with 500 kt.yr exposure. The effects of statistical fluctuations, systematic errors, and uncertainties in oscillation parameters have been incorporated using multiple sets of simulated data. This method would provide a direct and robust measurement of NSI in the multi-GeV energy range.