A Measurement of the psi-prime to J / psi production ratio in 920-GeV proton-nucleus interactions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Eur.Phys.J.C 49 (2007) 545-558, 2007.
Inspire Record 722216 DOI 10.17182/hepdata.57451

Ratios of the Psi' over the J/psi production cross sections in the dilepton channel for C, Ti and W targets have been measured in 920 GeV proton-nucleus interactions with the HERA-B detector at the HERA storage ring. The Psi' and J/psi states were reconstructed in both the mu+mu- and the e+e- decay modes. The measurements covered the kinematic range -0.35 < x_F < 0.1 with transverse momentum p_T < 4.5 GeV/c. The Psi' to J/psi production ratio is almost constant in the covered x_F range and shows a slow increase with p_T. The angular dependence of the ratio has been used to measure the difference of the Psi' and J/psi polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is R_psi'(mu)/R_psi'(e)=1.00+-0.08+-0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B'(mu)*B(e))/(B(mu)*B'(e)), of Psi' and J/psi in the two channels.

3 data tables

Ratio of PSI(3685) and J/PSI cross sections for both muon and electron channels combined, obtained for different cos theta in the s-channel helicity frame.

Ratio of PSI(3685) and J/PSI cross sections for both muon and electron channels combined, obtained for intervals inpT using the data from all targets.

Ratio of PSI(3685) and J/PSI production cross sections per nucleus.


J/psi and psi' production and their normal nuclear absorption in proton nucleus collisions at 400-GeV.

The NA50 collaboration Alessandro, B. ; Alexa, C. ; Arnaldi, R. ; et al.
Eur.Phys.J.C 48 (2006) 329, 2006.
Inspire Record 733916 DOI 10.17182/hepdata.57412

We report a new measurement of J/psi, psi' and Drell-Yan cross-sections, in the kinematical domain $-0.425&lt;y_{\rm cm}&lt;0.575$ and $-0.5&lt;\cos\theta_{\rm CS}&lt;0.5$, performed at the CERN-SPS using 400 GeV/c incident protons on Be, Al, Cu, Ag, W and Pb targets. The dependence of the charmonia production cross-sections on the size of the target nucleus allows to quantify the so-called normal nuclear absorption. In the framework of the Glauber model, this new measurement is combined with results previously obtained with the same apparatus, under different experimental conditions, and leads to a precise determination of the J/psi and psi' absorption cross-sections in the surrounding nuclear matter.

4 data tables

Production cross sections, per taregt nucleon for J/PSI and PSI(3685) and for Drell-Yann dimuon in the mass range of 2.9-4.5 GeV/c**, integrated in the phase space windows of the measurement.

Ratios of J/PSI, PSI(3685) and Drel Yann production cross sections, and for Drell-Yann dimuon in the mass range of 2.9-4.5 GeV/c**, integrated in the phase space windows of the measurement.

Absorption cross-section obtained with Glauber fits results only from this analysis.

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