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Jet-like correlations with neutral pion triggers in pp and central Pb–Pb collisions at 2.76 TeV

  • Author(s): Adam, J
  • Adamová, D
  • Aggarwal, MM
  • Aglieri Rinella, G
  • Agnello, M
  • Agrawal, N
  • Ahammed, Z
  • Ahmad, S
  • Ahn, SU
  • Aiola, S
  • Akindinov, A
  • Alam, SN
  • Albuquerque, DSD
  • Aleksandrov, D
  • Alessandro, B
  • Alexandre, D
  • Alfaro Molina, R
  • Alici, A
  • Alkin, A
  • Alme, J
  • Alt, T
  • Altinpinar, S
  • Altsybeev, I
  • Alves Garcia Prado, C
  • An, M
  • Andrei, C
  • Andrews, HA
  • Andronic, A
  • Anguelov, V
  • Anson, C
  • Antičić, T
  • Antinori, F
  • Antonioli, P
  • Aphecetche, L
  • Appelshäuser, H
  • Arcelli, S
  • Arnaldi, R
  • Arnold, OW
  • Arsene, IC
  • Arslandok, M
  • Audurier, B
  • Augustinus, A
  • Averbeck, R
  • Azmi, MD
  • Badalà, A
  • Baek, YW
  • Bagnasco, S
  • Bailhache, R
  • Bala, R
  • Balasubramanian, S
  • Baldisseri, A
  • Baral, RC
  • Barbano, AM
  • Barbera, R
  • Barile, F
  • Barnaföldi, GG
  • Barnby, LS
  • Barret, V
  • Bartalini, P
  • Barth, K
  • Bartke, J
  • Bartsch, E
  • Basile, M
  • Bastid, N
  • Basu, S
  • Bathen, B
  • Batigne, G
  • Batista Camejo, A
  • Batyunya, B
  • Batzing, PC
  • Bearden, IG
  • Beck, H
  • Bedda, C
  • Behera, NK
  • Belikov, I
  • Bellini, F
  • Bello Martinez, H
  • Bellwied, R
  • Belmont-Moreno, E
  • Beltran, LGE
  • Belyaev, V
  • Bencedi, G
  • Beole, S
  • Berceanu, I
  • Bercuci, A
  • Berdnikov, Y
  • Berenyi, D
  • Bertens, RA
  • Berzano, D
  • Betev, L
  • Bhasin, A
  • Bhat, IR
  • Bhati, AK
  • Bhattacharjee, B
  • et al.
Abstract

© 2016 The Author(s) We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta 8>pTtrig>16 GeV/c and associated charged particles of 0.5>pTassoc>10 GeV/c versus the azimuthal angle difference Δφ at midrapidity in pp and central Pb–Pb collisions at sNN=2.76 TeV with ALICE. The new measurements exploit associated charged hadrons down to 0.5 GeV/c, which significantly extends our previous measurement that only used charged hadrons above 3 GeV/c. After subtracting the contributions of the flow background, v2to v5, the per-trigger yields are extracted for |Δφ|>0.7 on the near and for |Δφ−π|>1.1 on the away side. The ratio of per-trigger yields in Pb–Pb to those in pp collisions, IAA, is measured on the near and away side for the 0–10% most central Pb–Pb collisions. On the away side, the per-trigger yields in Pb–Pb are strongly suppressed to the level of IAA≈0.6 for pTassoc<3 GeV/c, while with decreasing momenta an enhancement develops reaching about 5 at low pTassoc. On the near side, an enhancement of IAAbetween 1.2 at the highest to 1.8 at the lowest pTassocis observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high pTassoc. Only AMPT captures the enhancement at low pTassoc, both on the near and away side. However, it also underpredicts IAAabove 5 GeV/c, in particular on the near-side.

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