Measurement of the ($\pi^-$, Ar) total hadronic cross section at the LArIAT experiment

TL;DR

This paper reports the first measurement of the negative pion total hadronic cross section on argon using the LArIAT experiment, introducing a new 'thin slice method' with results generally higher than predictions but within model uncertainties.

Contribution

The paper introduces the 'thin slice method' for measuring hadronic cross sections with LArTPCs, providing new experimental data on pion-argon interactions.

Findings

Measured cross section is generally higher than predictions.

Results agree with Geant4 model within 5.1% uncertainty.

First such measurement on argon at these energies.

Abstract

We present the first measurement of the negative pion total hadronic cross section on argon, which we performed at the Liquid Argon In A Testbeam (LArIAT) experiment. All hadronic reaction channels, as well as hadronic elastic interactions with scattering angle greater than 5~degrees are included. The pions have a kinetic energies in the range 100-700~MeV and are produced by a beam of charged particles impinging on a solid target at the Fermilab Test Beam Facility. LArIAT employs a 0.24~ton active mass Liquid Argon Time Projection Chamber (LArTPC) to measure the pion hadronic interactions. For this measurement, LArIAT has developed the ``thin slice method", a new technique to measure cross sections with LArTPCs. While generally higher than the prediction, our measurement of the ($\pi^-$,Ar) total hadronic cross section is in agreement with the prediction of the Geant4 model when considering a model uncertainty of $\sim$5.1\%.