Upsilon (nS) polarizations versus particle multiplicity in pp collisions at root s=7 TeV

Khachatryan, V.; Adzic, R.; Ćirković, Predrag; Devetak, Damir; Milošević, Jovan; Rekovic, V.; Đorđević, Miloš; Milenović, Predrag

doi:10.1016/j.physletb.2016.07.065

2016

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Authors

Khachatryan, V.
Adzic, R.
Ćirković, Predrag

Devetak, Damir

Milošević, Jovan

Rekovic, V.
Đorđević, Miloš

Milenović, Predrag

CMS Collaboration (ukupan broj autora: 2285)

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Abstract

The polarizations of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) mesons are measured as a function of the charged particle multiplicity in proton-proton collisions at root s = 7 TeV. The measurements are performed with a dimuon data sample collected in 2011 by the CMS experiment, corresponding to an integrated luminosity of 4.9fb(-1). The results are extracted from the dimuon decay angular distributions, in two ranges of Upsilon(nS) transverse momentum (10-15 and 15-35 GeV), and in the rapidity interval |y| LT 1.2. The results do not show significant changes from low-to high-multiplicity pp collisions, although large uncertainties preclude definite statements in the Upsilon(2S) and Upsilon(3S) cases. (C) 2016 The Author(s). Published by Elsevier B.V.

Keywords:

CMS / Physics / Quarkonium production / Quarkonium polarization / QCD medium effects

Source:
Physics Letters B, 2016, 761, 31-52

Projects:

BMWFW (Austria), FWF (Austria), F.R.S. - FNRS (Belgium), CNPq (Brazil), CAPES (Brazil), FAPERJ (Brazil), FAPESP (Brazil), MES (Bulgaria), CERN, CAS (China), MOST (China), NSFC (China), COLCIENCIAS (Colombia), MSES (Croatia), CSF (Croatia), RPF (Cyprus), MoER (Estonia), ERC IUT (Estonia), ERDF (Estonia), Academy of Finland, MEC (Finland), HIP (Finland), CEA (France), CNRS/IN2P3 (France), BMBF, Germany, DFG (Germany), HGF (Germany), GSRT (Greece), OTKA (Hungary), NIH (Hungary), DAE (India), DST (India), IPM (Iran), SFI (Ireland), INFN (Italy), MSIP (Republic of Korea), NRF (Republic of Korea), LAS (Lithuania), MOE (Malaysia), UM (Malaysia), CINVESTAV (Mexico), CONACYT (Mexico), SEP (Mexico), UASLP-FAI (Mexico), MBIE (New Zealand), PAEC (Pakistan), MSHE (Poland), NSC (Poland), FCT (Portugal), JINR (Dubna), MON (Russia), RosAtom (Russia), RAS (Russia), RFBR (Russia), MESTD (Serbia), SEIDI (Spain), CPAN (Spain), Swiss Funding Agencies (Switzerland), MST (Taipei), ThEPCenter (Thailand), IPST (Thailand), STAR (Thailand), NSTDA (Thailand), TUBITAK (Turkey), TAEK (Turkey), NASU (Ukraine), SFFR (Ukraine), STFC (United Kingdom), DOE (USA), NSF (USA), Marie-Curie programme, European Research Council, EPLANET (European Union), Leventis Foundation, Alfred P. Sloan Foundation, Alexander von Humboldt Foundation, Belgian Federal Science Policy Office, Fonds pour la Formation a la Recherche dans lIndustrie et dans lAgriculture (FRIA-Belgium), Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium), Ministry of Education, Youth and Sports (MEYS) of the Czech Republic, Council of Science and Industrial Research, India, HOMING PLUS programme of the Foundation for Polish Science, European Union, Regional Development Fund, OPUS programme of the National Science Center (Poland), Compagnia di San Paolo (Torino), MIUR (Italy) [20108T4XTM], Thalis programme - EU-ESF, Aristeia programme - EU-ESF, Greek NSRF, National Priorities Research Program by Qatar National Research Fund, Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University (Thailand), Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand), Welch Foundation [C-1845]