A New Approach to Probe Non-Standard Interactions in Atmospheric Neutrino Experiments

Download Talk

Conference: APS April Meeting 2021 (Online), USA

Presentation mode: Online

Abstract: We propose a new approach to explore the neutral-current non-standard neutrino interactions (NSI) in atmospheric neutrino experiments using oscillation dips and valleys in reconstructed muon observables, at a detector like ICAL. We show that the non-zero value of NSI parameter ε_μτ shifts the oscillation dip locations in 𝐿/𝐸 distributions of the up/down event ratios of reconstructed μ^- and μ⁺ in opposite directions. We introduce a new variable Δd representing the difference of dip locations in μ^- and μ⁺, which is sensitive to ε_μτ, and is independent of the value of Δm²₃₂. We further note that the oscillation valley in the (E, cosθ) plane of the reconstructed muon observables bends in the presence of NSI, its curvature having opposite signs forμ^- and μ⁺. We illustrate how the measurement of contrast in the curvatures of valleys in μ^- and μ⁺ can be used to estimate ε_μτ. Using these proposed oscillation dip and valley measurements, the achievable precision on |ε_μτ| at 90% C.L. is about 2% with 500 kt⋅yr exposure including the effects of statistical fluctuations, systematic errors, and uncertainties in oscillation parameters.