The track-length extension fitting algorithm for energy measurement of interacting particles in liquid argon TPCs and its performance with ProtoDUNE-SP data

TL;DR

This paper presents a new track-length extension fitting algorithm for accurately measuring the energies of inelastically interacting particles in liquid argon TPCs, demonstrating its effectiveness with ProtoDUNE-SP data and simulations.

Contribution

It introduces a novel energy measurement algorithm based on track length extension fitting that accounts for energy loss models and detector response, applicable to inelastic interactions.

Findings

Achieves specific energy resolution and bias metrics for stopping pions

Demonstrates the algorithm's performance with ProtoDUNE-SP data and simulations

Shows the impact of dE/dx modeling on energy measurement accuracy

Abstract

This paper introduces a novel track-length extension fitting algorithm for measuring the kinetic energies of inelastically interacting particles in liquid argon time projection chambers (LArTPCs). The algorithm finds the most probable offset in track length for a track-like object by comparing the measured ionization density as a function of position with a theoretical prediction of the energy loss as a function of the energy, including models of electron recombination and detector response. The algorithm can be used to measure the energies of particles that interact before they stop, such as charged pions that are absorbed by argon nuclei. The algorithm's energy measurement resolutions and fractional biases are presented as functions of particle kinetic energy and number of track hits using samples of stopping secondary charged pions in data collected by the ProtoDUNE-SP detector, and also in a detailed simulation. Additional studies describe the impact of the dE/dx model on energy measurement performance. The method described in this paper to characterize the energy measurement performance can be repeated in any LArTPC experiment using stopping secondary charged pions.