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Measurement of the inclusive J/ ψ polarization at forward rapidity in pp collisions at √s=8 TeV

  • Author(s): Acharya, S
  • Acosta, FT
  • Adamová, D
  • Adolfsson, J
  • Aggarwal, MM
  • Aglieri Rinella, G
  • Agnello, M
  • Agrawal, N
  • Ahammed, Z
  • Ahn, SU
  • Aiola, S
  • Akindinov, A
  • Al-Turany, M
  • Alam, SN
  • Albuquerque, DSD
  • Aleksandrov, D
  • Alessandro, B
  • Alfaro Molina, R
  • Ali, Y
  • Alici, A
  • Alkin, A
  • Alme, J
  • Alt, T
  • Altenkamper, L
  • Altsybeev, I
  • Andrei, C
  • Andreou, D
  • Andrews, HA
  • Andronic, A
  • Angeletti, M
  • Anguelov, V
  • Anson, C
  • Antičić, T
  • Antinori, F
  • Antonioli, P
  • Anwar, R
  • Apadula, N
  • 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
  • Baldisseri, A
  • Ball, M
  • Baral, RC
  • Barbano, AM
  • Barbera, R
  • Barile, F
  • Barioglio, L
  • Barnaföldi, GG
  • Barnby, LS
  • Barret, V
  • Bartalini, P
  • Barth, K
  • Bartsch, E
  • Bastid, N
  • Basu, S
  • Batigne, G
  • Batista Camejo, A
  • Batyunya, B
  • Batzing, PC
  • Bazo Alba, JL
  • Bearden, IG
  • Beck, H
  • Bedda, C
  • Behera, NK
  • Belikov, I
  • Bellini, F
  • Bello Martinez, H
  • Bellwied, R
  • Beltran, LGE
  • Belyaev, V
  • Bencedi, G
  • Beole, S
  • Bercuci, A
  • Berdnikov, Y
  • Berenyi, D
  • Bertens, RA
  • Berzano, D
  • Betev, L
  • Bhaduri, PP
  • Bhasin, A
  • Bhat, IR
  • et al.
Abstract

© 2018, CERN for the benefit of the ALICE collaboration. We report on the measurement of the inclusive J/ψ polarization parameters in pp collisions at a center of mass energy s=8 TeV with the ALICE detector at the LHC. The analysis is based on a data sample corresponding to an integrated luminosity of 1.23 pb- 1. J/ψ resonances are reconstructed in their di-muon decay channel in the rapidity interval 2.5 < y< 4.0 and over the transverse-momentum interval 2 < pT< 15 GeV / c. The three polarization parameters (λθ, λφ, λθφ) are measured as a function of pT both in the helicity and Collins-Soper reference frames. The measured J/ψ polarization parameters are found to be compatible with zero within uncertainties, contrary to expectations from all available predictions. The results are compared with the measurement in pp collisions at s=7 TeV.

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