Kinematic Fit for the Radiative Bhabha Calibration of BaBar's Electromagnetic Calorimeter

TL;DR

This paper describes a kinematic fitting algorithm used for calibrating BaBar's electromagnetic calorimeter through radiative Bhabha events, ensuring accurate photon energy measurement.

Contribution

It introduces a detailed derivation and validation of a kinematic fit algorithm specifically for calorimeter calibration in particle physics experiments.

Findings

The fitting routine accurately matches measured and fitted photon energies.

Validation checks confirm the algorithm's proper functioning.

The method improves calibration precision for the calorimeter.

Abstract

For the radiative Bhabha calibration of BaBar's electromagnetic calorimeter, the measured energy of a photon cluster is being compared with the energy obtained via a kinematic fit involving other quantities from that event. The details of the fitting algorithm are described in this note, together with its derivation and checks that ensure that the fitting routine is working properly.