Hadron Energy Reconstruction for the ATLAS Barrel Prototype Combined Calorimeter in the Framework of the Non-parametrical Method

TL;DR

This paper presents a non-parametrical method for hadron energy reconstruction in the ATLAS barrel calorimeter, achieving high accuracy and fast processing suitable for trigger systems, validated with CERN SPS pion data.

Contribution

The paper introduces a parameter-free, fast energy reconstruction method using known e/h ratios, applicable for real-time trigger systems in the ATLAS calorimeter.

Findings

Energy reconstruction within ±1% accuracy

Fractional energy resolution formula derived

e/h ratio for electromagnetic compartment measured as 1.74

Abstract

Hadron energy reconstruction for the Atlas barrel prototype combined calorimeter, consisting of the lead-liquid argon electromagnetic part and the iron-scintillator hadronic part, in the framework of the non-parametrical method has been fulfilled. This method uses only the known e/h ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique and can be used for the fast energy reconstruction in the first level trigger. The obtained reconstruction of the mean values of energies is within $\pm 1%$ and the fractional energy resolution is $[(58\pm3)% \sqrt{GeV}/\sqrt{E}+(2.5\pm0.3)%]\oplus (1.7\pm0.2) GeV/E$. The obtained value of the e/h ratio for electromagnetic compartment of the combined calorimeter is $1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this electromagnetic calorimeter. The results of the study of the longitudinal hadronic shower development are presented. The data have been taken in the H8 beam line of the CERN SPS using pions of 10 -- 300 GeV.