Analysis note: measurement of thrust and track energy-energy correlator in $e^+e^-$ collisions at 91.2 GeV with DELPHI open data

TL;DR

This paper measures thrust and track-based energy-energy correlator in $e^+e^-$ collisions at 91.2 GeV using DELPHI open data, providing high-resolution event shape data for testing QCD predictions.

Contribution

First physics analysis using DELPHI open data, introducing high-precision measurements of event shapes and energy-energy correlators for QCD studies.

Findings

Event shapes measured with unprecedented resolution.

Data agrees with certain Monte Carlo and analytic models.

Provides benchmarks for future analyses with DELPHI data.

Abstract

Recent theoretical developments, as well as experimental measurements at hadron collisions, have renewed interest in studying event shape variables in $e^+e^-$ collisions. We present a measurement of thrust and track-based energy-energy correlator in $e^+e^-$ collisions at center-of-mass energy of 91.2 GeV, using newly released open data from the DELPHI experiment. The event shapes, measured with unprecedented resolution and precision, are compared to various Monte Carlo and analytic predictions. Leveraging DELPHI's unique detector geometry and reconstruction capabilities, the track energy-energy correlator measurement provides data with the highest angular resolution, offering critical inputs for precision tests of QCD in both collinear and back-to-back limits. This note presents the first physics analysis using DELPHI open data and establishes benchmarks necessary for future studies exploiting this legacy dataset.