Neutrino events within muon bundles at neutrino telescopes

M Gutiérrez,G Hernández-Tomé,J.I Illana,M Masip

doi:10.1016/j.astropartphys.2021.102646

M Gutiérrez, G Hernández-Tomé + Show 2 more

Open Access

https://doi.org/10.1016/j.astropartphys.2021.102646

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Journal: Astroparticle Physics	Publication Date: Sep 5, 2021
Citations: 2	License type: cc-by

Affiliation: University of Granada

Abstract

The atmospheric neutrino flux includes a component from the prompt decay of charmed hadrons that becomes significant only at E≥10TeV. At these energies, however, the diffuse flux of cosmic neutrinos discovered by IceCube seems to be larger than the atmospheric one. Here we study the possibility to detect a neutrino interaction in down-going atmospheric events at km3 telescopes. The neutrino signal will always appear together with a muon bundle that reveals its atmospheric origin and, generically, it implies an increase in the detector activity with the slant depth. We propose a simple algorithm that could separate these events from regular muon bundles.

Highlights

The flux of atmospheric leptons, both muons and neutrinos, is sensitive to the multiplicity and the inelasticity in proton–air, pion–air and gamma–air collisions, probing a forward kinematical region and a high energy regime that are difficult to access at colliders
Our analysis will involve two main aspects that we study by using the air shower simulator CORSIKA [23]: (i) the relation between a neutrino of given energy and the energy of its parent air shower and (ii) the characterization of muon bundles from cosmic rays (CRs) primaries of any energy and composition
The determination of the atmospheric neutrino flux at energies from about 1 TeV up to several 100 TeV is essential both in the search for atmospheric charm and for a precise characterization of the high energy diffuse flux recently discovered by IceCube. This atmospheric flux is difficult to access with ν telescopes, as at E ≈ 10 TeV it seems to be 5–10 times weaker than the astrophysical one

Summary

Introduction

The flux of atmospheric leptons, both muons and neutrinos, is sensitive to the multiplicity and the inelasticity in proton–air, pion–air and gamma–air collisions, probing a forward kinematical region and a high energy regime that are difficult to access at colliders. Pions of energy above 30 GeV become less effective producing leptons in the air, as their decay length grows longer than their interaction length This softens the high-energy spectrum of atmospheric neutrinos, changing their power law from approximately E−2.7 to about E−3.7 [1]. In π− collisions with Carbon and Platinum targets at 500 GeV they observed forward events of large x where the c goes into a D0 or the cinto a D− much more likely than into a D+ or a D 0, respectively These leading charm hadrons appearing in the fragmentation region share a valence quark with the incident pion, suggesting a process of coalescence during hadronization.

Neutrinos and their parent cosmic ray

Leading muon and muon bundle

Neutrino events within a bundle

Findings

Summary and discussion