Compact Muon Solenoid
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| CMS-HIN-12-007 ; CERN-PH-EP-2014-240 | ||
| Measurement of prompt $\psi(2\mathrm{S})$ to $\mathrm{J}/\psi$ yield ratios in PbPb and pp collisions at $\sqrt{s_\mathrm{NN}}$ = 2.76 TeV | ||
| CMS Collaboration | ||
| 8 October 2014 | ||
| Phys. Rev. Lett. 113 (2014) 262301 | ||
| Abstract: The ratio between the prompt $\psi(2\mathrm{S})$ and $\mathrm{J}/\psi$ yields, reconstructed via their decays into $\mu^+\mu^-$, is measured in PbPb and pp collisions at $\sqrt{s_\mathrm{NN}}$ = 2.76 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC, corresponding to integrated luminosities of 150 $ \mu \mathrm{b}^{-1} $ and 5.4 $ \mathrm{pb}^{-1} $, respectively. The double ratio of measured yields, $ ( N_{\psi(2\mathrm{S})} / N_{ \mathrm{J} / \psi} )_{ \mathrm{Pb} \mathrm{Pb} } / ( N_{ \psi( 2 \mathrm{S} ) } / N_{ \mathrm{J} / \psi} )_{ \mathrm{p} \mathrm{p} } $, is computed in three PbPb collision centrality bins and two kinematic ranges: one at midrapidity, $ | y | < $ 1.6, covering the transverse momentum range 6.5 $ < p_{\mathrm{T}} < $ 30 GeV/$c$, and the other at forward rapidity, 1.6 $ < | y | < $ 2.4, extending to lower $p_{\mathrm{T}}$ values, 3 $ < p_{\mathrm{T}} < $ 30 GeV/$c$. The centrality-integrated double ratio changes from 0.45 $\pm$ 0.13 (stat) $\pm$ 0.07 (syst) in the first range to 1.67 $\pm$ 0.34 (stat) $\pm$ 0.27 (syst) in the second. This difference is most pronounced in the most central collisions. | ||
| Links: e-print arXiv:1410.1804 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; Public twiki page ; HepData record ; CADI line (restricted) ; | ||
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Compact Muon Solenoid LHC, CERN |
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