CERN Accelerating science

CMS Note
Report number	CMS-CR-2012-250
Title	Measurements of jet shape in 2.76 TeV PbPb collisions with CMS
Author(s)	Mao, Yaxian (Vanderbilt U.)
Publication	2012
Collaboration	CMS Collaboration
Imprint	04 Oct 2012
Number of pages	5
Presented at	23rd International Conference on Ultrarelativistic Nucleus-Nucleus Collisions, Washington, DC, USA, 13 - 18 Aug 2012
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Abstract	The fragmentation properties of inclusive jets produced in PbPb collisions at a center of mass energy of $\sqrt{s_{_{\mathrm{NN}}}} = $2.76 TeV are characterized by measuring differential jet shapes. The jet shape is defined as the fractional jet transverse momentum carried by charged particles emitted at a distance $r$ from the jet axis, with jets reconstructed using the anti-$k_T$ clustering algorithm. The jet shapes are measured for reconstructed jet $p_{\mathrm{T,jet}}>100$ GeV/$c$ and charged hadrons with $p_T > 1$ GeV/$c$. Different background subtraction methods are studied to remove the contribution from the underlying events. The results obtained for PbPb collisions as a function of collision centrality are compared to reference distributions from pp data collected at the same collision energy. For the most central collisions, modifications of the jet shape are observed at large distance from the jet axis.
Copyright/License	Preprint: (License: CC-BY-4.0)