Beta Spectrum Generator: High precision allowed $\beta$ spectrum shapes

TL;DR

The paper introduces a high-precision, flexible C++ tool for calculating allowed beta spectrum shapes with all necessary corrections, supporting neutrino physics and nuclear data integration.

Contribution

A new C++ implementation of an analytical allowed beta spectrum shape with comprehensive corrections and user-friendly interfaces, enabling high-precision beta decay studies.

Findings

Achieves accuracy of a few parts in 10^4 in spectrum calculations

Supports interface with advanced nuclear structure models

Provides accessible tools for neutrino spectrum analysis

Abstract

Several searches for Beyond Standard Model physics rely on an accurate and highly precise theoretical description of the allowed $\beta$ spectrum. Following recent theoretical advances, a C++ implementation of an analytical description of the allowed beta spectrum shape was constructed. It implements all known corrections required to give a theoretical description accurate to a few parts in $10^4$. The remaining nuclear structure-sensitive input can optionally be calculated in an extreme single-particle approximation with a variety of nuclear potentials, or obtained through an interface with more state-of-the-art computations. Due to its relevance in modern neutrino physics, the corresponding (anti)neutrino spectra are readily available with appropriate radiative corrections. In the interest of user-friendliness, a graphical interface was developed in Python with a coupling to a variety of nuclear databases. We present several test cases and illustrate potential usage of the code. Our work can be used as the foundation for current and future high-precision experiments related to the beta decay process. Source code: https://github.com/leenderthayen/BSG Documentation: http://bsg.readthedocs.io