@article{adb8ff447d31486eb902de1a56f5419d,
title = "Measurement of the inclusive J/ ψ polarization at forward rapidity in pp collisions at √s=8 TeV",
abstract = "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.",
author = "\{ALICE Collaboration\} and S. Acharya and Acosta, \{F. T.\} and D. Adamov{\'a} and J. Adolfsson and Aggarwal, \{M. M.\} and \{Aglieri Rinella\}, G. and M. Agnello and N. Agrawal and Z. Ahammed and Ahn, \{S. U.\} and S. Aiola and A. Akindinov and M. Al-Turany and Alam, \{S. N.\} and Albuquerque, \{D. S.D.\} and D. Aleksandrov and B. Alessandro and \{Alfaro Molina\}, R. and Y. Ali and A. Alici and A. Alkin and J. Alme and T. Alt and L. Altenkamper and I. Altsybeev and C. Andrei and D. Andreou and Andrews, \{H. A.\} and A. Andronic and M. Angeletti and V. Anguelov and C. Anson and T. Anti{\v c}i{\'c} and F. Antinori and P. Antonioli and R. Anwar and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and R. Arnaldi and Arnold, \{O. W.\} and Arsene, \{I. C.\} and M. Arslandok and B. Audurier and A. Augustinus and R. Averbeck and P. Cortese and L. Ramello and M. Sitta",
note = "Publisher Copyright: {\textcopyright} 2018, CERN for the benefit of the ALICE collaboration.",
year = "2018",
month = jul,
day = "1",
doi = "10.1140/epjc/s10052-018-6027-2",
language = "English",
volume = "78",
journal = "European Physical Journal C",
issn = "1434-6044",
publisher = "Springer New York",
number = "7",
}