Can one distinguish τ-neutrinos from antineutrinos in neutral-current pion production processes?

E Hernández,M Valverde,J Nieves

doi:10.1016/j.physletb.2007.02.051

Abstract

A potential way to distinguish τ -neutrinos from antineutrinos, below the τ -production threshold, but above the pion production one, is presented. It is based on the different behavior of the neutral-current pion production off the nucleon, depending on whether it is induced by neutrinos or antineutrinos. This procedure for distinguishing τ -neutrinos from antineutrinos neither relies on any nuclear model, nor it is affected by any nuclear effect (distortion of the outgoing nucleon waves, etc.). We show that neutrino–antineutrino asymmetries occur both in the totally integrated cross sections and in the pion azimuthal differential distributions. To define the asymmetries for the latter distributions we just rely on Lorentz-invariance. All these asymmetries are independent of the lepton family and can be experimentally measured by using electron or muon neutrinos, due to the lepton family universality of the neutral-current neutrino interaction. Nevertheless and to estimate their size, we have also used the chiral model of [E. Hernández, J. Nieves, M. Valverde, hep-ph/0701149 ] at intermediate energies. Results are really significant since the differences between neutrino and antineutrino induced reactions are always large in all physical channels.

Highlights

Distinguishing τ −neutrinos from antineutrinos, can be done above the τ −production threshold energy, since the charged–current (CC) channel is open
The authors of this reference conclude that these asymmetries represent a potential way to distinguish neutrinos from antineutrinos in NC neutrino scattering on nuclei
We present in this letter an alternative manner to distinguish τ −neutrinos from antineutrinos, below the τ −production threshold (≈ 3.5 GeV in the Laboratory (LAB) frame for production off the nucleon), but above the pion production one (≈ 0.15 GeV in the LAB frame)

Summary

Introduction

Distinguishing τ −neutrinos from antineutrinos, can be done above the τ −production threshold energy, since the charged–current (CC) channel is open. The method is based on the different behavior of the NC pion production reaction in the nucleon, depending on whether it is induced by neutrinos or antineutrinos.

Results

Conclusion