Tracking Performance of the ATLAS Inner Detector and Observation of Known Hadrons

TL;DR

This paper evaluates the ATLAS inner detector's tracking performance using collision data at 900 GeV and 7 TeV, demonstrating its ability to identify known hadrons and measure charged particle densities.

Contribution

It presents the first detailed performance assessment of the ATLAS inner detector with real collision data, including resonance identification and efficiency estimation methods.

Findings

Successful reconstruction of $ ext{J}/ ext{ extpsi}$ and $ ext{ extpsi}(2S)$ mesons.

Identification of $ ext{ extXi}$ and $ ext{ extOmega}$ baryons in cascade decays.

Data-driven track reconstruction efficiency estimation.

Abstract

The inner detector is the central tracking device of the ATLAS detector. In these proceedings the tracking performance of the inner detector is presented on collision data recorded at $\sqrt{s}$ = 900 GeV and 7 TeV. The identification of resonances like $\Xi$ and $\Omega$ baryons in cascade decays via $K_{\mathrm{s}}$ and $\Lambda$ mesons is presented as well as the reconstruction of the $J / \psi $ and $\psi$(2S) mesons decaying into two muons. Furthermore, the performance of the track reconstruction and a data-driven method of estimating the track reconstruction efficiency as used in measurements of charged particle densities are discussed.