CMS-PAS-BPH-13-003

CMS-PAS-BPH-13-003
Prompt psi(2S) polarization in pp collisions at 7 TeV
CMS Collaboration
2013

Abstract: The polarization of prompt $\psi$ (2S) mesons ismeasured in proton-proton collisions at $\sqrt{s} = 7\,$ TeV, using a data sample of $\psi\mathrm{(2S)} \rightarrow \mu^+\mu^-$ decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 $\,$ fb $^{-1}$ . The dimuon decay angular distributions are analysed in three different polarization frames. The prompt $\psi$ (2S) polarization parameters $\lambda_\vartheta$ , $\lambda_\varphi$ , and $\lambda_{\vartheta\varphi}$ , as well as the frame-invariant $\tilde{\lambda}$ , are measured as a function of the $\psi$ (2S) transverse momentum, $p_{\rm T}$ , between 14 and 50 $\,$ GeV, in the rapidity ranges $\|y\|<0.6$ and .6<\|y\|<1.2$. No evidence of large transverse or longitudinal polarizations is seen in the explored kinematic region.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, PLB 727 (2013) 381. The superseded preliminary plots can be found here.

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