Fast and Accurate Algorithm for Calculating Long-Baseline Neutrino Oscillation Probabilities with Matter Effects: NuFast

TL;DR

This paper introduces NuFast, a fast and precise algorithm for calculating neutrino oscillation probabilities in matter, optimized for long-baseline experiments, facilitating large-scale Monte Carlo simulations.

Contribution

The paper presents a novel, optimized algorithm and accompanying code for efficient calculation of neutrino oscillation probabilities in matter, improving speed and accuracy for long-baseline experiments.

Findings

Significantly faster computation of oscillation probabilities.

High accuracy maintained in matter effects calculations.

Applicable to both accelerator and reactor experiments.

Abstract

Neutrino oscillation experiments will be entering the precision era in the next decade with the advent of high statistics experiments like DUNE, HK, and JUNO. Correctly estimating the confidence intervals from data for the oscillation parameters requires very large Monte Carlo data sets involving calculating the oscillation probabilities in matter many, many times. In this paper, we leverage past work to present a new, fast, precise technique for calculating neutrino oscillation probabilities in matter optimized for long-baseline neutrino oscillations in the Earth's crust including both accelerator and reactor experiments. For ease of use by theorists and experimentalists, we provide fast c++ and fortran codes.