Measurement of Transverse Single-Spin Asymmetries for J/psi Production in Polarized p+p Collisions at sqrt(s) = 200 GeV

Abstract

We report the first measurement of transverse single-spin asymmetries in $J/\ddot{I}ˆ$ production from transversely polarized $p+p$ collisions at $\sqrt{s}=200$ GeV with data taken by the PHENIX experiment in 2006 and 2008. The measurement was performed over the rapidity ranges $1.2<|y|<2.2$ and $|y|<0.35$ for transverse momenta up to 6 GeV/$c$. $J/\ddot{I}ˆ$ production at RHIC is dominated by processes involving initial-state gluons, and transverse single-spin asymmetries of the $J/\ddot{I}ˆ$ can provide access to gluon dynamics within the nucleon. Such asymmetries may also shed light on the long-standing question in QCD of the $J/\ddot{I}ˆ$ production mechanism. Asymmetries were obtained as a function of $J/\ddot{I}ˆ$ transverse momentum and Feynman-$x$, with a value of $-0.086\pm 0.026^{\mathrm{stat}}\pm 0.003^{\mathrm{syst}}$ in the forward region. This result suggests possible nonzero trigluon correlation functions in transversely polarized protons and, if well defined in this reaction, a nonzero gluon Sivers distribution function.

431 authors from 62 institutions, 13 pages, 5 figures, and 5 tables. Submitted to Physical Review D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.html