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

0492085 - ÚJF 2019 RIV US eng J - Journal Article
Acharya, S. - Acosta, F. T. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Broz, M. - Contreras, J. G. - Horák, D. - Křížek, Filip - Kučera, Vít - Kushpil, Svetlana - Lavička, R. - Mareš, Jiří A. - Petráček, V. - Šumbera, Michal - Závada, Petr … Total 1012 authors
Measurement of the inclusive J/psi polarization at forward rapidity in pp collisions at root s=8 TeV.
European Physical Journal C. Roč. 78, č. 7 (2018), č. článku 562. ISSN 1434-6044. E-ISSN 1434-6052
R&D Projects: GA MŠMT(CZ) LTT17018
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : ALICE * heavy ion collisions * quarkonium production
OECD category: Nuclear physics; Particles and field physics (FZU-D)
Impact factor: 4.843, year: 2018

We report on the measurement of the inclusive J/psi polarization parameters in pp collisions at a center of mass energy root 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/psi 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 (lambda(theta), lambda(phi), lambda(theta phi)) are measured as a function of pT both in the helicity and Collins-Soper reference frames. The measured J/psi 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 root s = 7 TeV.
Permanent Link: http://hdl.handle.net/11104/0285648