Solving inverse problems with the unfolding program TRUEE: Examples in astroparticle physics

TL;DR

TRUEE is a C++ software package for solving inverse problems in physics, extending the stable and reliable unfolding algorithm originally in FORTRAN77, with improved usability demonstrated on astrophysics data.

Contribution

The paper introduces TRUEE, a new user-friendly C++ implementation of an established unfolding algorithm for inverse problems, with enhanced features and application to astrophysics datasets.

Findings

TRUEE provides stable unfolding results consistent with the original RUN algorithm.

The software simplifies installation and parameter selection for users.

Application to MAGIC and IceCube data demonstrates its effectiveness.

Abstract

The unfolding program TRUEE is a software package for the numerical solution of inverse problems. The algorithm was first applied in the FORTRAN77 program RUN. RUN is an event-based unfolding algorithm which makes use of the Tikhonov regularization. It has been tested and compared to different unfolding applications and stood out with notably stable results and reliable error estimation. TRUEE is a conversion of RUN to C++, which works within the powerful ROOT framework. The program has been extended for more user-friendliness and delivers unfolding results which are identical to RUN. Beside the simplicity of the installation of the software and the generation of graphics, there are new functions, which facilitate the choice of unfolding parameters and observables for the user. In this paper, we introduce the new unfolding program and present its performance by applying it to two exemplary data sets from astroparticle physics, taken with the MAGIC telescopes and the IceCube neutrino detector, respectively.