Absolute Polarization Measurements at RHIC in the Coulomb Nuclear Interference Region

01/2007; DOI: 10.1063/1.2750925
Source: arXiv

ABSTRACT The Relativistic Heavy Ion Collider at Brookhaven National Laboratory provides polarized proton beams for the investigation of the nucleon spin structure. For polarimetry, carbon-proton and proton-proton scattering is used in the Coulomb nuclear interference region at small momentum transfer ($-t$). Fast polarization measurements of each beam are carried out with carbon fiber targets at several times during an accelerator store. A polarized hydrogen gas jet target is needed for absolute normalization over multiple stores, while the target polarization is constantly monitored in a Breit-Rabi polarimeter. In 2005, the jet polarimeter has been used with both RHIC beams. We present results from the jet polarimeter including a detailed analysis of background contributions to asymmetries and to the beam polarization.


Available from: A. Nass, Sep 24, 2014
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    ABSTRACT: The large mass of the charm quark, along with the abundance of J/psi mesons observed from proton-proton collisions at PHENIX, allow for new measurements which are sensitive to basic properties of QCD. Two measurements are presented in this document: a transverse single-spin asymmetry (SSA) of J/psi production and the angular distribution for decay leptons in various reference frames. The decay distribution is directly sensitive to the J/psi production mechanism, while the transverse SSA is also sensitive to the distribution of gluons in a transversely polarized proton. Taken together, the two measurements provide a wealth of information about the formation of a J/psi meson.