Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

TL;DR

This paper measures the calorimeter response to single hadrons and propagates these uncertainties to the jet energy scale in the ATLAS detector, achieving a 1-5% uncertainty range crucial for precise physics analyses at the LHC.

Contribution

It provides a detailed measurement of the calorimeter response to various particles and quantifies the jet energy scale uncertainty for the ATLAS experiment.

Findings

Response uncertainty is 2-5% for central isolated hadrons.

Response uncertainty is 1-3% for the jet energy scale.

Calorimeter response measurements agree with Monte Carlo predictions.

Abstract

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.