Geometric calibration of the SND detector electromagnetic calorimeter

TL;DR

This paper details a software-based geometric calibration method for the SND detector's electromagnetic calorimeter, improving particle reconstruction accuracy by aligning it with the tracking system using data-driven optimization.

Contribution

Introduces a novel mathematical model and calibration procedure for precise geometric alignment of the calorimeter relative to the tracking system in the SND detector.

Findings

Calibration improves particle direction reconstruction accuracy.

Model fits data and simulation well.

Calibration procedure is validated with real and simulated data.

Abstract

This paper presents the design, implementation and validation of the software alignment procedure used to perform geometric calibration of the electromagnetic calorimeter with respect to the tracking system of the SND detector which is taking data at the VEPP-2000 e^{+}e^{-}collider (BINP, Novosibirsk). This procedure is based on the mathematical model describing the relative calorimeter position. The parameter values are determined by minimizing a \chi^{2} function using the difference between particle directions reconstructed in these two subdetectors for e^{+}e^{-}\rightarrow e^{+}e^{-} scattering events. The results of the calibration applied to data and MC simulation fit the model well and give an improvement in particle reconstruction. They are used in data reconstruction and MC simulation.