TauRunner: A Public Python Program to Propagate Neutral and Charged Leptons

TL;DR

TauRunner is a Python package that accurately simulates the propagation of neutral and charged leptons at ultra-high energies, accounting for secondary neutrinos and stochastic tau energy losses, aiding future neutrino observatory research.

Contribution

It introduces TauRunner, a novel, adaptable Python tool for simulating lepton propagation at energies up to 10^{12} GeV, including secondary neutrino production and stochastic tau energy losses.

Findings

Supports energies from 10 GeV to 10^{12} GeV

Accounts for secondary neutrino production in interactions

Includes stochastic treatment of tau energy losses

Abstract

In the past decade IceCube's observations have revealed a flux of astrophysical neutrinos extending to $10^{7}~\rm{GeV}$. The forthcoming generation of neutrino observatories promises to grant further insight into the high-energy neutrino sky, with sensitivity reaching energies up to $10^{12}~\rm{GeV}$. At such high energies, a new set of effects becomes relevant, which was not accounted for in the last generation of neutrino propagation software. Thus, it is important to develop new simulations which efficiently and accurately model lepton behavior at this scale. We present TauRunner a PYTHON-based package that propagates neutral and charged leptons. TauRunner supports propagation between $10~\rm{GeV}$ and $10^{12}~\rm{GeV}$. The package accounts for all relevant secondary neutrinos produced in charged-current tau neutrino interactions. Additionally, tau energy losses of taus produced in neutrino interactions is taken into account, and treated stochastically. Finally, TauRunner is broadly adaptable to divers experimental setups, allowing for user-specified trajectories and propagation media, neutrino cross sections, and initial spectra.