Double Neutrino Production and Detection in Neutrino Detectors

TL;DR

This paper calculates the expected rate of double-neutrino events from a single cosmic-ray air shower in large neutrino detectors, highlighting their significance as a background in new physics searches.

Contribution

It introduces the first detailed calculation of double-neutrino interaction rates in large-scale neutrino telescopes, emphasizing their importance as an irreducible background.

Findings

Rate of about 0.07 events/year for IceCube-like detectors.

Rate of about 0.8 events/year for KM3Net-like detectors.

Double neutrino interactions are a significant background in supersymmetry searches.

Abstract

Large, high-energy ($E>100$ GeV) cosmic neutrino telescopes are now quite mature. IceCube, for example, observes about 50,000 well-reconstructed single atmospheric neutrino events/year, with energies above 100 GeV. Although the neutrino detection probability is small, current detectors are large enough so that it is possible to detect two neutrinos from the same cosmic-ray interaction. In this paper, we calculate the expected rate of double-neutrino interactions from a single cosmic-ray air shower. The rate is small, about 0.07 events/year for a 1 km$^3$ detector like IceCube, with only a small dependence on the assumed cosmic-ray composition and hadronic interaction model. For a larger detector, like the proposed KM3Net, the rate is about 0.8 events/year, a rate that should be easily observable. These double neutrino interactions are the major irreducible background to searches of pairs of particles produced in supersymmetric neutrino or cosmic-ray air-shower interactions. Other standard-model backgrounds are considered, and found to be small.