Measurements of b-jet nuclear modification factors in pPb and PbPb collisions with CMS

Jung, K. and Khachatryan, V. and Sirunyan, A. M. and Tumasyan, A. and Adam, W. and Bergauer, T. and Dragicevic, M. and Erö, J. and Fabjan, C. and Friedl, M. and Frühwirth, R. and Ghete, V. M. and Hartl, C. and Hörmann, N. and Hrubec, J. and Jeitler, M. and Kiesenhofer, W. and Knünz, V. and Krammer, M. and Krätschmer, I. and Liko, D. and Mikulec, I. and Rabady, D. and Rahbaran, B. and Rohringer, H. and Schöfbeck, R. and Strauss, J. and Taurok, A. and Treberer-Treberspurg, W. and Waltenberger, W. and Filipovic, Nicolas and Bencze, György and Hajdu, Csaba and Hidas, Pál and Horváth, Dezső and Siklér, Ferenc and Veszprémi, Viktor and Vesztergombi, György and Zsigmond, Anna Júlia and Karancsi, János and Molnár, József and Ujvári, Balázs and Veres, Gábor (2014) Measurements of b-jet nuclear modification factors in pPb and PbPb collisions with CMS. NUCLEAR PHYSICS A, 931. pp. 470-474. ISSN 0375-9474

Preview

Text 1410.2576.pdf Available under License Creative Commons Attribution. Download (290kB) | Preview

Abstract

We present measurements of the nuclear modification factors RAA and RPYT HIA pA of b jets in lead-lead and proton-lead collisions, respectively, using the CMS detector. Jets from b-quark fragmentations are found by exploiting the long lifetime of the b-quark through tagging methods using distributions of the secondary vertex displacement. From these, b-jet cross-sections are calculated and compared to the pp cross-section from the 2.76 TeV pp data collected in 2013 and to a PYTHIA simulation at 5.02 TeV, where these center-of-mass energies correspond to those of the PbPb and pPb data. We observe significant suppression for b jets in PbPb, and a RPYT HIA pA value consistent with unity for b jets in pPb. Results from both collision species show remarkable correspondance with inclusive-jet suppression measurements, indicating that mass-dependent energy-loss effects are negligible at pT values greater than around 50 GeV/c. We use 150 μb−1 of lead-lead data and 35 nb−1 of proton-lead data collected at the LHC.

Actions (login required)

Edit Item