High-energy neutrino event simulation at NLO in Genie for KM3NeT and other observatories

TL;DR

This paper extends the GENIE neutrino event generator to simulate high-energy neutrino interactions up to 10^10 GeV at NLO accuracy, improving the precision and applicability for neutrino observatories like KM3NeT.

Contribution

It introduces a high-energy extension of GENIE with NLO formalism, interfacing PYTHIA6 for hadronization, enabling accurate simulation of neutrino interactions up to 10^10 GeV.

Findings

Extended GENIE to 10^10 GeV energy range

Incorporated NLO cross sections and modern PDFs

Simulated heavy quark production including top and bottom

Abstract

High-energy neutrino astronomy is a key pillar of multi-messenger astronomy and has the potential to also advance fundamental neutrino physics. An accurate simulation of the neutrino interactions is key in any analysis of neutrino telescope data. The currently available generator codes of neutrino interactions use leading order expressions for the differential cross sections which govern rate and kinematics of the events. These calculations are affected by well-known large theoretical uncertainties, hence the need of beyond leading order formalism. Also, a consistent use of modern Parton Density Functions, which are derived using NLO (or NNLO) frameworks, is required. For this reason and others, the GENIE event generator of neutrino interactions, which is a standard tool in the few-GeV energy regime, has so far been stated to be valid up to only about 1 TeV. The work reported here consists of a high-energy (up to 10$^{10}$ GeV) extension, which will be available in GENIEv4. It interfaces PYTHIA6 for the hadronization and employs a pragmatic method to assign the flavour of the struck and outgoing quarks, so that the heavy quark production, including bottom and top, is also correctly simulated.