Central exclusive quarkonium production with tagged forward protons at RHIC

Harland-Lang, L.A.; Khoze, V.A.; Ryskin, M.G.; Stirling, W.J.

Abstract

We study the Central Exclusive Production (CEP) of χcJ and ηc mesons at RHIC in proton–proton collisions. We consider the χcJ→J/ψ + γ decay channels and, recalling that the Jz=0 suppression of the J=1,2 states can be compensated by their larger branchings to J/ψ + γ, present predictions of rates and distributions for χc(0,1,2) production. Particular attention is paid to the impact of p⊥ cuts applied to the outgoing protons, which can influence the relative rates significantly. The distribution in the azimuthal angle difference between the outgoing protons and the proton p2⊥p⊥2 is also studied, and shown to depend sensitively on the spin and parity of the centrally produced meson, as well as being affected by the soft-survival factors, S2. Two- and four-body decays, which are particularly relevant for χc0 production, are also considered. We show that in the two-body case, backgrounds from ‘direct’ QCD production based on both perturbative and non-perturbative models are expected to be under control.

Citation

Harland-Lang, L., Khoze, V., Ryskin, M., & Stirling, W. (2011). Central exclusive quarkonium production with tagged forward protons at RHIC. The European Physical Journal C, 71, Article 1545. https://doi.org/10.1140/epjc/s10052-011-1545-1

• Journal Article Type: Article
• Online Publication Date: Feb 8, 2011
• Publication Date: 2011-02
• Deposit Date: Jan 23, 2012
• Journal: European Physical Journal C: Particles and Fields
• Print ISSN: 1434-6044
• Electronic ISSN: 1434-6052
• Publisher: SpringerOpen
• Peer Reviewed: Peer Reviewed
• Volume: 71
• Article Number: 1545
• DOI: https://doi.org/10.1140/epjc/s10052-011-1545-1