HepLib: A C++ library for high energy physics

Abstract

HepLib is a C++ Library for computations in High Energy Physics, it works on top of GiNaC, a well-established C++ library used to perform symbolic computations. HepLib combines serval well-known packages to get high efficiency, including qgraf to generate Feynman aptitudes, FORM to perform Dirac/Color matrix related computations, and FIRE or KIRA for integration-by-parts (IBP) reduction. Another core feature of HepLib lies in the numerical evaluation of master integrals using sector decomposition, which is a general method widely used in high-order numerical computation and has been implemented in many public packages in many different languages, and we present another implementation in the language of C++ with many new features. We use GiNaC to handle the symbolic operations, and export the corresponding integrand into an optimized C++ code, that will be compiled internally and linked dynamically, a customizable numerical integrator is selected to perform the numerical integration, while the integrand can be evaluated in different float precisions, including the arbitrary precision supported by MPFR. Program summaryProgram Title:HepLibCPC Library link to program files:https://doi.org/10.17632/jspjxy3z66.1Developer's repository link:https://heplib.github.io/Licensing provisions:GPLv3Programming language:C++External libraries:GiNaC, qgraf, MPFR, Fermat, QHull, MinUit2, CUBAExternal programs:FORM, FIRE, KIRANature of problem: There are many independent programs or packages in high energy physics, which are written or developed in different programming languages, here we are trying to provide an integrated interface in the C++ language, for generating Feynman diagrams/amplitudes, performing algebraic simplifications on Dirac/Color matrix objects, and reducing scalar integrals to master integrals. The evaluation of master integrals is in the core part during the high-order calculations, one needs to resolve ultraviolet/infrared divergence within dimensional regularization and the singularities inside the integration domain while performing multiple dimensional numerical integrations.Solution method:HepLib uses qgraf to generate the Feynman diagrams/aptitudes, FORM to perform Dirac/Color matrix related computations, FIRE or KIRA for the IBP reduction. A C++ implementation of sector decomposition method is used to extract both ultraviolet and infrared singularity of the integral, the contour deformation is adopted to avoid the singularity inside the integration domain, a parallelized numerical integration is chosen to achieve high efficiency or performance.Restrictions: Depending on the complexity of the problem itself.