First Direct Measurement of Jets in $\sqrt{s_{NN}}=200$ GeV Heavy Ion Collisions by STAR

TL;DR

This paper reports the first direct measurement of reconstructed jets in ultra-relativistic heavy ion collisions at 200 GeV, using STAR detector data, modern algorithms, and background subtraction, comparing results with proton-proton collisions.

Contribution

It introduces the first measurement of jets in heavy ion collisions at this energy, demonstrating the application of advanced reconstruction techniques and systematic uncertainty analysis.

Findings

First direct jet measurement in heavy ion collisions at 200 GeV

Comparison of jet spectra with scaled proton-proton data

Assessment of systematic uncertainties in jet reconstruction

Abstract

We present the first measurement of reconstructed jets in ultra-relativistic heavy ion collisions. Utilizing the large coverage of the STAR Time Projection Chamber and Electromagnetic Calorimeter, we apply several modern jet reconstruction algorithms and background subtraction techniques and explore their systematic uncertainties in heavy ion events. The differential spectrum for inclusive jet production in central Au+Au collisions at $\sqrt {s_{NN}}= 200$ GeV is presented. In order to assess the jet reconstruction biases, this spectrum is compared with the jet cross section measured in $\sqrt{s}=200$ GeV p+p collisions scaled by the number of binary N-N collisions to account for nuclear geometric effects.