Transverse Spin and RHIC

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is the first accelerator facility that can accelerate, store and collide spin polarized proton beams. This development enables a physics program aimed at understanding how the spin of the proton results from its quark and gluon substructures. Spin states that are either parallel (longitudinal) or perpendicular (transverse) to the proton momentum reveal important insight into the structure of the proton. This talk outlines future plans for further studies of transverse spin physics at RHIC.Comment: 11 pages, 7 figures, Invited talk by L.C. Bland at the International Workshop on Transverse Polarisation Phenomena in Hard Processes (Transversity 2005), Villa Olmo (Como), 7-10 September 2005, to appear in the proceeding

Status of the RHIC Spin Program

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been developing the capability of accelerating, storing and colliding high-energy polarized proton beams over the past several years. During this development phase, important first measurements of cross sections and spin asymmetries for neutral pions produced in polarized proton collisions at $\sqrt{s}$=200 GeV have been completed by STAR and PHENIX, the two large collider experiments at RHIC. This contribution reports on progress of the RHIC spin program and provides an outlook for the future.Comment: 9 pages, Contribution to the Workshop on the Structure of the Nucleon at Large Bjorken x (HiX2004), Marseille, Luminy, July, 200

Transverse Single Spin Asymmetries in Hadronic Interactions: an experimental overview and outlook

Transverse single-spin asymmetries (SSA) are expected to be small in perturbative QCD because of the chiral nature of the theory. Experiment shows large transverse SSA for particle produced in special kinematics. This contribution reviews the experimental situation and provide an outlook for future measurements.Comment: 11 pages, 13 figures. Proceedings of Transversity 201

Discrete emotion-congruent false memories in the DRM paradigm

Research has shown that false memory production is enhanced for material that is emotionally congruent with the mood of the participant at the time of encoding. So far this research has only examined the influence of generic negative affective mood states and generic negative stimuli on false memory production. In addition, much of the research is limited as it focuses on valence and arousal dimensions, and fails to take into account the more comprehensive nature of emotions. The current study demonstrates that this effect goes beyond general negative or positive moods and acts at a more discrete emotional level. Participants underwent a standard emotion induction procedure before listening to negative emotional or neutral associative word lists. The emotions induced, negative word lists and associated non-presented critical lures, were related to either fear or anger, two negative valence emotions that are also both high in arousal. Results showed that when valence and arousal are controlled for, false memories are more likely to be produced for discrete emotionally congruent compared to incongruent materials. These results support spreading activation theories of false remembering and add to our understanding of the adaptive nature of false memory production

Threshold Resummation for W-Boson Production at RHIC

We study the resummation of large logarithmic perturbative corrections to the partonic cross sections relevant for the process pp -> W^+- X at the BNL Relativistic Heavy Ion Collider (RHIC). At RHIC, polarized protons are available, and spin asymmetries for this process will be used for precise measurements of the up and down quark and anti-quark distributions in the proton. The corrections arise near the threshold for the partonic reaction and are associated with soft-gluon emission. We perform the resummation to next-to-leading logarithmic accuracy, for the rapidity-differential cross section. We find that resummation leads to relatively moderate effects on the cross sections and spin asymmetries.Comment: 25 pages, 15 figures as eps files. One reference added and typo correcte

Direct observation of domain-wall configurations transformed by spin currents

Direct observations of current-induced domain-wall propagation by spin-polarized scanning electron microscopy are reported. Current pulses move head-to-head as well as tail-to-tail walls in sub-micrometer Fe_{20}Ni_{80} wires in the direction of the electron flow, and a decay of the wall velocity with the number of injected current pulses is observed. High-resolution images of the domain walls reveal that the wall spin structure is transformed from a vortex to a transverse configuration with subsequent pulse injections. The change in spin structure is directly correlated with the decay of the velocity.Comment: 5 pages, 3 figure