Longitudinal and transverse spin asymmetries for inclusive jet   production at mid-rapidity in polarized p+p collisions at sqrt{s}=200 GeV
  We report STAR measurements of the longitudinal double-spin asymmetry A_LL, the transverse single-spin asymmetry A_N, and the transverse double-spin asymmetries A_Sigma and A_TT for inclusive jet production at mid-rapidity in polarized p+p collisions at a center-of-mass energy of sqrt{s} = 200 GeV. The data represent integrated luminosities of 7.6 /pb with longitudinal polarization and 1.8 /pb with transverse polarization, with 50-55% beam polarization, and were recorded in 2005 and 2006. No evidence is found for the existence of statistically significant jet A_N, A_Sigma, or A_TT at mid-rapidity. Recent model calculations indicate the A_N results may provide new limits on the gluon Sivers distribution in the proton. The asymmetry A_LL significantly improves the knowledge of gluon polarization in the nucleon. 
The STAR Collaboration: L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z.   Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alfo...
nucl-ex