2 research outputs found
Forward Neutral Pion Transverse Single Spin Asymmetries in p+p Collisions at \sqrt{s}=200 GeV
We report precision measurements of the Feynman-x dependence, and first
measurements of the transverse momentum dependence, of transverse single spin
asymmetries for the production of \pi^0 mesons from polarized proton collisions
at \sqrt{s}=200 GeV. The x_F dependence of the results is in fair agreement
with perturbative QCD model calculations that identify orbital motion of quarks
and gluons within the proton as the origin of the spin effects. Results for the
p_T dependence at fixed x_F are not consistent with pQCD-based calculations.Comment: 6 pages, 4 figure
Indications of Conical Emission of Charged Hadrons at the BNL Relativistic Heavy Ion Collider
Three-particle azimuthal correlation measurements with a high transverse
momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at
200 GeV by the STAR experiment. Dijet structures are observed in pp, d+Au and
peripheral Au+Au collisions. An additional structure is observed in central
Au+Au data, signaling conical emission of correlated charged hadrons. The
conical emission angle is found to be 1.37 +- 0.02(stat) +0.06-0.07(syst),
independent of pt.Comment: 7 pages, 4 figures, 1 tabl