Deep Core muon neutrino rate and anisotropy by mixing and CPT violation

TL;DR

This paper predicts anisotropic muon neutrino rates in Deep Core due to oscillations and CPT violation, suggesting observable differences in muon track distributions that could test fundamental symmetries.

Contribution

It provides a new rate prediction for atmospheric muon neutrinos in Deep Core, considering oscillation effects and CPT violation, with specific anisotropy signatures.

Findings

Predicted large anisotropy in muon neutrino rates across different channels.

Expected suppression of muon rates at certain channels due to oscillations.

Potential for testing CPT violation through observed anisotropies.

Abstract

Neutrinos are allowed to mix and to oscillate among their flavor. Muon and tau in particular oscillate at largest values.Last Minos experiment claimed possible difference among their matter and anti-matter masses, leading to a first violation of the most believed CPT symmetry.Isotropically born atmospheric muon neutrino at 20-80 GeV, while up-going, they might be partially suppressed by mixing in analogy to historical SuperKamiokande muon neutrino disappearance into tau, leading to large scale anisotropy signals. Here we show an independent muon rate foreseen in Deep Core based on observed SK signals extrapolated to DeepCore mass and its surrounding. Our rate prediction partially differ from previous ones. The neutrino muon disappearance into tau is leading to an anisotropy in vertical up-going muon track: in particular along channel 3-5 we expect a huge rate (tens of thousand of events) of neutral current events, charged current electron and inclined crossing muons. Moreover at channel 6-9 we expect a severe suppression of the rate due to muon disappearance (in CPT conserved frame). Such an anisotropy might be partially tested by more than one string detection at E> 45 GeV energy. A CPT violation may induce a more remarkable suppression of vertical up-going tracks because of larger anti-neutrino muon reduction for E> 35 GeV.