Measurement of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) Polarizations in pp Collisions at root s 7 TeV

Chatrchyan, S.; Adžić, Petar; Đorđević, Miloš; Ekmedzic, M.; Krpic, D.; Milošević, Jovan; Milenović, Predrag; Rekovic, V.

doi:10.1103/PhysRevLett.110.081802

2013

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Authors

Chatrchyan, S.
Adžić, Petar
Đorđević, Miloš

Ekmedzic, M.
Krpic, D.
Milošević, Jovan

Milenović, Predrag

Rekovic, V.

CMS Collaboration (ukupan broj autora: 2182)

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Abstract

The polarizations of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) mesons are measured in proton-proton collisions at root s = 7 TeV, using a data sample of Upsilon(nS) - GT mu(+)mu(-) decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb(-1). The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization parameters lambda(theta), lambda(phi), and lambda(theta phi), as well as the frame-invariant quantity (lambda) over tilde, are presented as a function of the Upsilon(nS) transverse momentum between 10 and 50 GeV, in the rapidity ranges vertical bar y vertical bar LT 0: 6 and 0: 6 LT vertical bar y vertical bar LT 1.2. No evidence of large transverse or longitudinal polarizations is seen in the explored kinematic region. DOI: 10.1103/PhysRevLett.110.081802

Source:
Physical Review Letters, 2013, 110, 8

Projects:

BMWF (Austria), FWF (Austria), FNRS (Belgium), FWO (Belgium), CNPq (Brazil), CAPES (Brazil), FAPERJ (Brazil), FAPESP (Brazil), MES (Bulgaria), CERN (China), CAS (China), MoST (China), NSFC (China), COLCIENCIAS (Colombia), MSES (Croatia), RPF (Cyprus), MoER (Estonia) [SF0690030s09], ERDF (Estonia), Academy of Finland, MEC (Finland), HIP (Finland), CEA (France), CNRS/IN2P3 (France), BMBF, Germany, DFG (Germany), HGF (Germany), GSRT (Greece), OTKA (Hungary), NKTH (Hungary), DAE (India), DST (India), IPM (Iran), SFI (Ireland), INFN (Italy), NRF (Korea), WCU (Korea), LAS (Lithuania), CINVESTAV (Mexico), CONACYT (Mexico), SEP (Mexico), UASLP-FAI (Mexico), MSI (New Zealand), PAEC (Pakistan), MSHE (Poland), NSC (Poland), FCT (Portugal), JINR (Armenia), JINR (Belarus), JINR (Georgia), JINR (Ukraine), JINR (Uzbekistan), MON (Russia), RosAtom (Russia), RAS (Russia), RFBR (Russia), MSTD (Serbia), SEIDI (Spain), CPAN (Spain), Swiss Funding Agencies (Switzerland), NSC (Taipei), TUBITAK (Turkey), TAEK (Turkey), STFC (United Kingdom), DOE (USA), NSF (USA)