Quark Matter 2014 - XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

Semi-inclusive recoil jet distribution and di-jets imbalance measurements in central Au+Au collisions in STAR

21 May 2014, 09:40

20m

titanium (darmstadtium)

Contributed Talk Jets Jets

Speaker

Joern Putschke (Wayne State University)

Description

The measurement of fully reconstructed jets in heavy ion collisions provides unique probes of the Quark-Gluon Plasma (QGP). However, full jet reconstruction in such events is challenging due to a large population of combinatorial background "jets" that overwhelm the true hard jet population by several orders of magnitude. In order to carry out accurate, data-driven jet measurements over a broad kinematic range at RHIC energies, we developed a novel mixed-event technique that describes the combinatorial jet background over several orders of magnitude with high precision. We apply this technique to measure the semi-inclusive charged jet distribution recoiling from a high $p_T$ hadron trigger in central Au+Au collisions at $\sqrt{s_{NN}}=$200 GeV. We report the recoil jet distribution for various trigger $p_T$ ranges and jet radii, and study the azimuthal distribution between the recoil jet and trigger hadron. In addition we present the first measurement at RHIC of the di-jet transverse momentum asymmetry, $A_J$. Both measurements are performed with a very low infrared cutoff on jet constituents of 200 MeV. These jet coincidence measurements allow a direct comparison of jet quenching at RHIC and the LHC.

Presentation materials

Slides

qm14_star_dijet_putschke.pdf