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

ALICE Collaboration

Research output: Contribution to journalArticle

1 Citation (Scopus)

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, λθ φ) 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.

Original languageEnglish
Article number562
JournalEuropean Physical Journal C
Volume78
Issue number7
DOIs
Publication statusPublished - 2018 Jul 1

Fingerprint

Polarization
collisions
polarization
intervals
transverse momentum
center of mass
muons
Luminance
Momentum
luminosity
Detectors
detectors
decay
predictions
energy
Uncertainty

All Science Journal Classification (ASJC) codes

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

Cite this

@article{5a1c414556b84deeb76464c8c87f7c66,
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, λθ φ) 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. Antičić 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 Azmi, {M. D.} and A. Badal{\`a} and Youngjoon Kwon",
year = "2018",
month = "7",
day = "1",
doi = "10.1140/epjc/s10052-018-6027-2",
language = "English",
volume = "78",
journal = "European Physical Journal C",
issn = "1434-6044",
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Measurement of the inclusive J/ ψ polarization at forward rapidity in pp collisions at √s=8 TeV. / ALICE Collaboration.

In: European Physical Journal C, Vol. 78, No. 7, 562, 01.07.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Measurement of the inclusive J/ ψ polarization at forward rapidity in pp collisions at √s=8 TeV

AU - ALICE Collaboration

AU - Acharya, S.

AU - Acosta, F. T.

AU - Adamová, D.

AU - Adolfsson, J.

AU - Aggarwal, M. M.

AU - Aglieri Rinella, G.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahn, S. U.

AU - Aiola, S.

AU - Akindinov, A.

AU - Al-Turany, M.

AU - Alam, S. N.

AU - Albuquerque, D. S.D.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfaro Molina, R.

AU - Ali, Y.

AU - Alici, A.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Altenkamper, L.

AU - Altsybeev, I.

AU - Andrei, C.

AU - Andreou, D.

AU - Andrews, H. A.

AU - Andronic, A.

AU - Angeletti, M.

AU - Anguelov, V.

AU - Anson, C.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Anwar, R.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arnold, O. W.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Audurier, B.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Azmi, M. D.

AU - Badalà, A.

AU - Kwon, Youngjoon

PY - 2018/7/1

Y1 - 2018/7/1

N2 - 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, λθ φ) 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.

AB - 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, λθ φ) 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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UR - http://www.scopus.com/inward/citedby.url?scp=85049776261&partnerID=8YFLogxK

U2 - 10.1140/epjc/s10052-018-6027-2

DO - 10.1140/epjc/s10052-018-6027-2

M3 - Article

VL - 78

JO - European Physical Journal C

JF - European Physical Journal C

SN - 1434-6044

IS - 7

M1 - 562

ER -