CHIRON: a package for ChPT numerical results at two loops

TL;DR

CHIRON is a comprehensive C++ package providing numerical routines for two-loop calculations in Chiral Perturbation Theory, including integrals, parameters, and finite volume effects, facilitating advanced theoretical research.

Contribution

It introduces a new software package that integrates two-loop ChPT calculations with finite volume effects and parameter management, enhancing computational tools in the field.

Findings

Includes routines for masses, decay constants, and vacuum expectation values.

Provides finite volume correction calculations for masses and decay constants.

Features a library of numerical routines, including dilogarithm and Jacobi theta functions.

Abstract

This document describes the package CHIRON which includes two libraries, chiron itself and jbnumlib. CHIRON is a set of routines useful for two-loop numerical results in Chiral Perturbation Theory (ChPT). It includes programs for the needed one- and two-loop integrals as well as routines to deal with the ChPT parameters. The present version includes everything needed for the masses, decay constants and quark-antiquark vacuum-expectation-values. An added routine calculates consistent values for the masses and decay constants when the pion and kaon masses are varied. In addition a number of finite volume results are included: one-loop tadpole integrals, two-loop sunset integrals and the results for masses and decay constants. The numerical routine library jbnumlib contains the numerical routines used in chiron. Many are to a large extent simple C++ versions of routines in the CERNLIB numerical library. Notable exceptions are the dilogarithm and the Jacobi theta function implementations. This paper describes what is included in CHIRON v0.50.