Investigating the role of coherence effects on jet quenching in Pb-Pb collisions at √sNN = 2.76 TeV using jet substructure
Acharya, Shreyasi; Adam, Jaroslav; Adamová, Dagmar; Adolfsson, Jonatan; Aggarwal, Madan M.; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Nikita; Ahammed, Zubayer; Ahmad, Nazeer; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Alba, José Luis Bazo; Albuquerque, D.S.D.; Aleksandrov, Dimitry; Alessandro, Bruno; Alfaro Molina, José Rubén; Alici, Andrea; Alkin, Anton; Alme, Johan; Altenkaemper, Lucas; Arsene, Ionut Christian; Bätzing, Paul Christoph; Djuvsland, Øystein; Dordic, Olja; Helstrup, Håvard; Hetland, Kristin Fanebust; Kileng, Bjarte; Langøy, Rune; Lardeux, Antoine Xavier; Lien, Jørgen; Lindal, Svein; Lønne, Per-Ivar; Mahmood, Sohail Musa; Milosevic, Jovan; Nesbø, Simon Voigt; Nystrand, Joakim; Rehman, Attiq ur; Richter, Matthias; Røed, Ketil; Røhrich, Dieter; Skaali, Toralf Bernhard; Tambave, Ganesh Jagannath; Tveter, Trine Spedstad; Ullaland, Kjetil; Velure, Arild; Wagner, Boris; Wikne, Jon Christopher; Zhang, Hui; Zhao, Chengxin; Zhou, Zhuo; Zhu, Hongsheng; ALICE, Collaboration
Journal article, Peer reviewed
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Original versionNuclear Physics A. 2017, 967 (2017), 560-563. 10.1016/j.nuclphysa.2017.05.055
We report measurements of two jet shapes, the ratio of 2-Subjettiness to 1-Subjettiness (τ2/τ1) and the opening angle between the two axes of the 2-Subjettiness jet shape, which is obtained by reclustering the jet with the exclusive-kT algorithm  and undoing the final clustering step. The aim of this measurement is to explore a possible change in the rate of 2-pronged objects in Pb-Pb compared to pp due to colour coherence. Coherence effects  relate to the ability of the medium to resolve a jet’s substructure, which has an impact on the energy loss magnitude and mechanism of the traversing jet. In both collision systems charged jets are found with the anti-kT algorithm , a resolution parameter of R =0.4 and a constituent cut off of 0.15 GeV. This analysis uses hadron-jet coincidence techniques in Pb-Pb collisions to reject the combinatorial background and corrects further for background effects by employing various jet shape subtraction techniques and two dimensional unfolding. Measurements of the Nsubjettiness for jet momenta of 40 – 60 GeV/c in Pb-Pb collisions at √sNN = 2.76 TeV and pp collisions at √s = 7 TeV will be presented and compared to PYTHIA simulations.