Recent Heavy Ion Results on the Hard Scattering and Jet Quenching from the ATLAS and CMS experiments at the LHC

Abstract

Recent results on studies of hard scattering processes and jet quenching in nuclear collisions from the ATLAS and CMS experiments at the Large Hadron Collider (LHC) are reviewed. They are based on high statistics samples of PbPb collisions at √ sNN = 2.76 TeV collected at the LHC in 2011, and pp collisions at √ s = 2.76 TeV and pPb collisions at √ sNN = 5.02 TeV collected in 2013. New results for the jet nuclear modification factor, RAA, confirm a strong suppression of jet production. Modifications of jet fragmentation properties in PbPb collisions, are observed. In pPb collisions jets are not strongly modified, but some non-scaling behavior of jet rates in collisions with different centralities is observed by ATLAS. New measurements for the electroweak boson production in pPb collisions allow a more precise testing of parton distributions in lead nuclei with the conclusion that the EPS09 description of nuclear modifications of parton distribution functions is preferred.