The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2

The double helicity asymmetry in neutral pion production for pT=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DeltaG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of micro2=4 GeV2 a next to leading order QCD analysis gives DeltaG[0.02,0.3]=0.2, with a constraint of -0.7

We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at sqrt[s]=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.

The strength of forward-backward (FB) multiplicity correlations is measured by the ALICE detector in proton-proton (pp) collisions at √ s = 0.9, 2.76 and 7 TeV. The measurement is performed in the central pseudorapidity region (|η| < 0.8) for the transverse momentum p T > 0.3 GeV/c. Two separate pseudorapidity windows of width (δη) ranging from 0.2 to 0.8 are chosen symmetrically around η = 0. The multiplicity correlation strength (b corr) is studied as a function of the pseudorapidity gap (η gap) between the two windows as well as the width of these windows. The correlation strength is found to decrease with increasing η gap and shows a non-linear increase with δη. A sizable increase of the correlation strength with the collision energy, which cannot be explained exclusively by the increase of the mean multiplicity inside the windows, is observed. The correlation coefficient is also measured for multiplicities in different configurations of two azimuthal sectors selected within the symmetric FB η-windows. Two different contributions, the short-range (SR) and the long-range (LR), are observed. The energy dependence of b corr is found to be weak for the SR component while it is strong for the LR component. Moreover, the correlation coefficient is studied for particles belonging to various transverse momentum intervals chosen to have the same mean multiplicity. Both SR and LR contributions to b corr are found to increase with p T in this case. Results are compared to PYTHIA and PHOJET event generators and to a string-based phenomenological model. The observed dependencies of b corr add new constraints on phenomenological models.

We present measurements of the J/ψ invariant yields in √ s N N =39 and 62.4 GeV Au+Au collisions at forward rapidity (1.2 < |y| < 2.2). Invariant yields are presented as a function of both collision