van Eldik C (2007)
Publication Language: English
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2007
Publisher: EDP Sciences: EPJ
Book Volume: 49
Pages Range: 545-558
Journal Issue: 2
DOI: 10.1140/epjc/s10052-006-0139-9
Ratios of the ψ′ over the J/ψ 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 ψ′ and J/ψ states were reconstructed in both the μμ and the ee decay modes. The measurements covered the kinematic range -0.35≤x≤0.1 with transverse momentum p≤4.5 GeV/c. The angular dependence of the ratio has been used to measure the difference of the ψ′ and J/ψ polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is R (μ)/R(e)=1.00±0. 08±0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B′(μ)B(e))/(B(μ) B′(e)), of ψ′ and J/ψ in the two channels. The ψ′ to J/ψ production ratio is almost constant in the covered x range and shows a slow increase with p. © Springer-Verlag Berlin Heidelberg 2007.
APA:
van Eldik, C. (2007). A measurement of the ψ′ to J/ψ production ratio in 920 GeV proton-nucleus interactions. European Physical Journal C, 49(2), 545-558. https://doi.org/10.1140/epjc/s10052-006-0139-9
MLA:
van Eldik, Christopher. "A measurement of the ψ′ to J/ψ production ratio in 920 GeV proton-nucleus interactions." European Physical Journal C 49.2 (2007): 545-558.
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