Updated measurements of exclusive J/ψ and ψ(2S) production cross-sections in pp collisions at √s= 7 TeV

The paper is available here.

arXiv: 1401.3288 J. Phys. G: Nucl. Part. Phys. 41 (2014) 055002.

More detailed information: ANA note 2013-058

Abstract

Abstract The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψ and ψ(2S) mesons in proton-proton collisions at √s = 7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb−1 . The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be

σpp→J/ψ →μ+ μ− (2.0 < ημ < 4.5) = 291 7 19 pb,

σpp→ψ(2S)→μ+ μ− (2.0 < ημ < 4.5) = 6.5 0.9 0.4 pb,

where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects.

Figures

(pdf and eps versions are available under attachments).

Caption Figure
Figure 1: Feynman diagrams displaying (a) exclusive J/ψ and (b) inelastic J/ψ production where a small number of additional particles are produced due to gluon radiation and (c),(d) proton dissociation. Equivalent diagrams apply for ψ(2S) production. Fig1.png
Figure 2: Acceptance for (solid) J/ψ and (dotted) ψ(2S) decays as a function of their rapidity. Fig2.png
Figure 3: Invariant mass distribution of muon pairs after the selection requirements. The horizontally hatched regions show the J/ψ (left) signal and (right) side-band regions. The diagonally hatched regions show the ψ(2S) (left) signal and (right) side-band regions. The data are fitted (solid curve) with Crystal Ball functions for the signals and an exponential function for the non-resonant background; the latter contribution is shown by the dashed curve. Fig3.png
Figure 4: Transverse momentum squared distributions for (a) J/ψ and (b) ψ(2S) candidates, where the non-resonant background contribution has been subtracted using side-bands. The points are data, the solid curve is the total fit while the different contributions are as described. Fig4a.pngFig4b.png
Figure 5: Differential cross-section for (a) J/ψ and (b) ψ(2S) production compared to LO and NLO predictions of [5]. The band indicates the total uncertainty, most of which is correlated between bins. Fig5a.pngFig5b.png
Figure 6: Photoproduction cross-section as a function of the centre-of-mass of the photon-proton system with the power-law fit from [8] superimposed. The LHCb data points for W+(W ) are derived assuming the power-law fit for W+(W ). The uncertainties are correlated between bins. Fixed target results are from the E401 [33], E516 [34] and E687 [35] collaborations. Fig6.png
Figure 7: Differential distribution for (a) J/ψ and (b) ψ(2S) compared to the predictions of Gay Ducati, Griep and Machado [3] and Motyka and Watt [2], which include saturation effects. The points are data where the error bars indicate the uncorrelated uncertainties. The band indicates the total uncertainty, most of which is correlated between bins. Fig7a.pngFig7b.png
J/ψ comparison with theory. This plot is not in the paper jpsi.png
ψ(2S) comparison with theory. This plot is not in the paper psi2s.png
-- KatharinaMueller - 15 Jan 2014
Topic attachments
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Unknown file formateps Fig1.eps r1 manage 132.8 K 2014-01-16 - 09:14 KatharinaMueller  
PDFpdf Fig1.pdf r1 manage 35.5 K 2014-01-16 - 09:14 KatharinaMueller  
PNGpng Fig1.png r1 manage 80.3 K 2014-01-16 - 09:14 KatharinaMueller  
Unknown file formateps Fig2.eps r1 manage 7.3 K 2014-01-16 - 09:14 KatharinaMueller  
PDFpdf Fig2.pdf r1 manage 13.3 K 2014-01-16 - 09:14 KatharinaMueller  
PNGpng Fig2.png r1 manage 10.5 K 2014-01-16 - 09:14 KatharinaMueller  
Unknown file formateps Fig3.eps r1 manage 64.3 K 2014-01-16 - 09:14 KatharinaMueller  
PDFpdf Fig3.pdf r1 manage 50.2 K 2014-01-16 - 09:14 KatharinaMueller  
PNGpng Fig3.png r1 manage 34.0 K 2014-01-16 - 09:14 KatharinaMueller  
Unknown file formateps Fig4a.eps r1 manage 14.2 K 2014-01-16 - 09:15 KatharinaMueller  
PDFpdf Fig4a.pdf r1 manage 20.1 K 2014-01-16 - 09:15 KatharinaMueller  
PNGpng Fig4a.png r1 manage 17.5 K 2014-01-16 - 09:15 KatharinaMueller  
PDFpdf Fig4b.pdf r1 manage 17.7 K 2014-01-16 - 09:15 KatharinaMueller  
PNGpng Fig4b.png r1 manage 16.5 K 2014-01-16 - 09:15 KatharinaMueller  
Unknown file formateps Fig5a.eps r1 manage 12.8 K 2014-01-16 - 09:15 KatharinaMueller  
PDFpdf Fig5a.pdf r1 manage 16.1 K 2014-01-16 - 09:15 KatharinaMueller  
PNGpng Fig5a.png r1 manage 14.7 K 2014-01-16 - 09:15 KatharinaMueller  
Unknown file formateps Fig5b.eps r1 manage 15.0 K 2014-01-16 - 09:15 KatharinaMueller  
PDFpdf Fig5b.pdf r1 manage 17.2 K 2014-01-16 - 09:15 KatharinaMueller  
PNGpng Fig5b.png r1 manage 16.9 K 2014-01-16 - 09:15 KatharinaMueller  
Unknown file formateps Fig6.eps r2 r1 manage 21.7 K 2014-02-20 - 13:44 KatharinaMueller  
PDFpdf Fig6.pdf r2 r1 manage 26.1 K 2014-02-20 - 13:44 KatharinaMueller  
PNGpng Fig6.png r2 r1 manage 15.9 K 2014-02-20 - 13:45 KatharinaMueller  
Unknown file formateps Fig7a.eps r1 manage 13.6 K 2014-01-16 - 09:15 KatharinaMueller  
PDFpdf Fig7a.pdf r1 manage 15.9 K 2014-01-16 - 09:15 KatharinaMueller  
PNGpng Fig7a.png r1 manage 15.8 K 2014-01-16 - 09:15 KatharinaMueller  
Unknown file formateps Fig7b.eps r1 manage 13.2 K 2014-01-16 - 09:16 KatharinaMueller  
PDFpdf Fig7b.pdf r1 manage 16.1 K 2014-01-16 - 09:16 KatharinaMueller  
PNGpng Fig7b.png r1 manage 15.1 K 2014-01-16 - 09:16 KatharinaMueller  
PDFpdf jpsi.pdf r1 manage 13.6 K 2014-02-20 - 10:58 KatharinaMueller  
PNGpng jpsi.png r1 manage 40.1 K 2014-02-20 - 10:58 KatharinaMueller  
PDFpdf psi2s.pdf r1 manage 13.5 K 2014-02-20 - 10:58 KatharinaMueller  
PNGpng psi2s.png r1 manage 18.4 K 2014-02-20 - 10:58 KatharinaMueller  
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