Transverse single-spin asymmetries of midrapidity and mesons in polarized collisions at GeV

Acharya, U. A.*; Hasegawa, Shoichi   ; Imai, Kenichi*; Sako, Hiroyuki   ; Sato, Susumu  ; Tanida, Kiyoshi   ; PHENIX Collaboration*; 309 of others*

We present a measurement of the transverse single-spin asymmetry for and mesons in collisions in the pseudorapidity range and at a center-of-mass energy of 200 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. In comparison with previous measurements in this kinematic region, these results have a factor of 3 smaller uncertainties. As hadrons, and mesons are sensitive to both initial- and final-state nonperturbative effects for a mix of parton flavors. Comparisons of the differences in their transverse single-spin asymmetries have the potential to disentangle the possible effects of strangeness, isospin, or mass. These results can constrain the twist-3 trigluon collinear correlation function as well as the gluon Sivers function.