Abstract
The STAR Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum hadron trigger, in central and peripheral Au + Au collisions at √sNN = 200 GeV. Charged jets are reconstructed with the anti-kT algorithm for jet radii R between 0.2 and 0.5 and with low infrared cutoff of track constituents (pT > 0.2 GeV/c). A novel mixed-event technique is used to correct the large uncorrelated background present in heavy ion collisions. Corrected recoil jet distributions are reported at midrapidity, for charged-jet transverse momentum pchT,jet < GeV/c. Comparison is made to similar measurements for Pb + Pb collisions at √s = 2.76 TeV, to calculations for p + p collisions at √s = 200 GeV based on the PYTHIA Monte Carlo generator and on a next-to-leading order perturbative QCD approach, and to theoretical calculations incorporating jet quenching. The recoil jet yield is suppressed in central relative to peripheral collisions, with the magnitude of the suppression corresponding to medium-induced charged energy transport out of the jet cone of 2.8 ± 0.2(stat) ± 1.5(sys) GeV/c, for 10 < pchT,jet < 20 GeV/c and R = 0.5. No medium-induced change in jet shape is observed for R < 0.5. The azimuthal distribution of low-pchT,jet recoil jets may be enhanced at large azimuthal angles to the trigger axis, due to scattering off quasiparticles in the hot QCD medium. Measurement of this distribution gives a 90% statistical confidence upper limit to the yield enhancement at large deflection angles in central Au + Au collisions of 50 ± 30(sys)% of the large-angle yield in p + p collisions predicted by pythia.
Document Type
Article
Publication Date
8-14-2017
Digital Object Identifier (DOI)
https://doi.org/10.1103/PhysRevC.96.024905
Repository Citation
Adamczyk, L.; Adkins, James K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Fatemi, Renee H.; and Ramachandran, Suvarna, "Measurement of Jet Quenching with Semi-Inclusive Hadron+Jet Distributions in Au + Au Collisions at √sNN = 200 GeV" (2017). Physics and Astronomy Faculty Publications. 529.
https://uknowledge.uky.edu/physastron_facpub/529
Notes/Citation Information
Published in Physical Review C, v. 96, issue 2, 024905, p. 1-25.
©2017 American Physical Society
The copyright holder has granted permission for posting the article here.
Due to the large number of authors, only the first 30 and the authors affiliated with the University of Kentucky are listed in the author section above. For the complete list of authors, please download this article or visit: https://doi.org/10.1103/PhysRevC.96.024905
This group of authors is collectively known as the STAR Collaboration.