Signatures of secondary leptons in radio-neutrino detectors in ice

Abstract

The detection of the radio emission following a neutrino interaction in ice is a promising technique to obtain significant sensitivities to neutrinos with energies above Petaelectronvolts (10 15 eV). The detectable radio emission stems from particle showers in the ice. So far, detector simulations have considered only the radio emission from the primary interaction of the neutrino. For this study, existing simulation tools have been extended to cover secondary interactions from muons and taus. We find that secondary interactions of both leptons add up to 25% to the effective volume of neutrino detectors. Also, muon and tau neutrinos can create several detectable showers, with the result that double signatures do not constitute an exclusive signature for tau neutrinos. We also find that the background of atmospheric muons from cosmic rays is non-negligible for in-ice arrays and that an air shower veto should be considered helpful for radio detectors.

Sensitivity studies for the IceCube-Gen2 radio array

“…The software packages NuRadioMC [9] and NuRadioReco [10] have been used for the generation and propagation of the Askaryan radio signal, and for the simulation of the detector response and event reconstruction, respectively. The simulation takes into account additional radio signals that are generated by muons and taus that were created by charge current interactions of the respective neutrino [11].…”

“…The inter-station coincidences provide two unique opportunities for event reconstruction: First, since different stations will see a different part of the Cherenkov cone, they can provide a sample of events with improved angular resolution. Second, multiple showers beyond PeV are expected not only for charged current interactions (the characteristic 'double-bang' signature) but also from catastrophic losses of and leptons along their trajectory [11]. Hence, the detection of multiple spatially separated showers can be used for flavor identification and to improve event reconstruction.…”

Prospects for neutrino-flavor physics with in-ice radio detectors

“…1). We further simulated a radio detector station at the South Pole with a phased array trigger at 100 m depth that was approximated by a single dipole antenna at a trigger threshold of 1.5 times the noise RMS in the frequency band from 100 MHz to 730 MHz and a noise temperature of 250 K. We performed the simulation once taking into account interference between showers (as described above) and a second time where each shower was treated individually (as done in our previous work [6]). We simulated exactly the same events which allows us to compare the results on an event-by-event basis.…”

“…For charged current (CC) interactions of electron neutrinos, the generated electron also induces an electromagnetic particle shower. The muon and tau leptons that are generated in CC interactions of the respective neutrinos were mostly ignored in systematic detector simulations which changed through the work first presented in [6], where a more detailed discussion of the signatures of secondary leptons in radio-neutrino detectors in ice are discussed. These proceedings summarize the findings, report on technical improvements and cross-checks made since, and present a new simulation for a detector at the South Pole.…”

“…This suggests that interference between showers should be taken into account when calculating the expected radio emission. In these proceedings, we present how NuRadioMC was modified to take into account interference between nearby showers which is an extension to our previous work where all showers were treated independently [6].…”