KinFit -- A Kinematic Fitting Package for Hadron Physics Experiments

TL;DR

KinFit is an open-source kinematic fitting software designed for hadron physics experiments, especially those with unknown interaction points, improving parameter resolution and event selection.

Contribution

The paper introduces KinFit, a versatile kinematic fitting package with vertex finding and constraint capabilities, tailored for complex hadron physics experiments.

Findings

KinFit enhances parameter resolution in simulated reactions.

It effectively aids in event selection processes.

The package is openly available on GitHub.

Abstract

A kinematic fitting package, KinFit, based on the Lagrange multiplier technique has been implemented for generic hadron physics experiments. It is particularly suitable for experiments where the interaction point is unknown, such as experiments with extended target volumes. The KinFit package includes vertex finding tools and fitting with kinematic constraints, such as mass hypothesis and four-momentum conservation, as well as combinations of these constraints. The new package is distributed as an open source software via GitHub. This paper presents a comprehensive description of the KinFit package and its features, as well as a benchmark study using Monte Carlo simulations of the $pp\rightarrow pK^+\Lambda \rightarrow pK^+p\pi^-$ reaction. The results show that KinFit improves the parameter resolution and provides an excellent basis for event selection.