Polarized Proton Collisions Research Articles

Physics with RHIC spin collider

The year 2002 has been very exciting and successful for the RHIC spin program, with the first collisions of polarized protons at √ s = 200 GeV, which is an order of magnitude higher energy than any previous polarized proton collisions. The achievements in the first year of the polarized collider are reported.

RHIC ACCELERATOR ADVANCES FOR SPIN

Spin physics has always had tight coupling between the physics, both experiment and theory, and accelerator physics. We have all benefited from the tradition of this close collaboration. This workshop is focused on physics issues, and this talk discusses recent advances in the accelerator/polarimetry areas for the RHIC spin program. The first polarized proton collisions at RHIC (and in the world) are planned for this winter. (Since the writing occurs near the end of this first run with polarized proton collisions, our instant analysis of this very successful run is included in this written version.)

Charmed hadron production in neutrino reactions and polarized s-quark distribution

In order to obtain information about the polarized strange quark distribution, we studied the semi-inclusive Λ c +/ Λ ̄ c + production in neutrino and polarized proton collisions. We found that these reactions are effective to clearly extract the polarization of strange quark by measuring the spin correlation between the target proton and the produced Λ c +/ Λ ̄ c + baryon.

Polarized proton collider at RHIC

In addition to heavy ion collisions (RHIC Design Manual, Brookhaven National Laboratory), RHIC will also collide intense beams of polarized protons (I. Alekseev, et al., Design Manual Polarized Proton Collider at RHIC, Brookhaven National Laboratory, 1998 [2]), reaching transverse energies where the protons scatter as beams of polarized quarks and gluons. The study of high energy polarized protons beams has been a long term part of the program at BNL with the development of polarized beams in the Booster and AGS rings for fixed target experiments. We have extended this capability to the RHIC machine. In this paper we describe the design and methods for achieving collisions of both longitudinal and transverse polarized protons in RHIC at energies up to s =500 GeV .

Spin physics program at RHIC: the first polarized-proton collider

Polarized pp collisions at high energy will provide a unique opportunity to study the spin structure of the nucleon and the symmetries in nature. The physics program with polarized beams at RHIC is overviewed with the expected sensitivities and the successful commissioning of the first polarized proton beam at RHIC is reported.

Spin physics program at RHIC: The first polarized-proton collider

Abstract Polarized pp collisions at high energy will provide a unique opportunity to study the spin structure of the nucleon and the symmetries in nature. The physics program with polarized beams at RHIC is overviewed with the expected sensitivities and the successful commissioning of the first polarized proton beam at RHIC is reported.

Electroproduction of ψ′ and polarized gluon distribution in a proton

In order to get information about the polarized gluon distribution in a proton, we studied the electroproduction of \psi' in polarized electron and polarized proton collisions in the framework of the NRQCD factorization approach. The value of the cross section d\Delta\sigma / dp_T^2 for color-octet mechanism is about 5 times larger than that for color-singlet one, and it might be another test of the color-octet model if the polarized gluon distribution \Delta g(x) is well known. Furthermore, we found that this reaction is quite effective for testing the model of gluon polarization by measuring the double spin asymmetry A_{LL} for the initial electron and proton. Though the shape of p_T^2 distribution of A_{LL} is quite similar for the production mechanism with color-octet and color-singlet, we can see a big difference in A_{LL} among various models of the polarized gluon distribution function \Delta g(x).

Prospects for Spin Physics at RHIC

▪ Abstract Colliding beams of 70% polarized protons at up to [Formula: see text] GeV, with high luminosity, L = 2 × 1032cm−2sec−1, will represent a new and unique laboratory for studying the proton. RHIC-Spin will be the first polarized-proton collider and will be capable of copious production of jets, directly produced photons, and W and Z bosons. Features will include direct and precise measurements of the polarization of the gluons and of [Formula: see text], u, and d quarks in a polarized proton. Parity violation searches for physics beyond the standard model will be competitive with unpolarized searches at the Fermilab Tevatron. Transverse spin will explore transversity for the first time, as well as quark-gluon correlations in the proton. Spin dependence of the total cross section and in the Coulomb nuclear interference region will be measured at collider energies for the first time. These qualitatively new measurements can be expected to deepen our understanding of the structure of matter and of the strong interaction.

RHIC spin physics — status of the polarized collider and spin-flavor structure of the nucleon

The Relativistic Heavy Ion Collider, which is under construction at Brookhaven National Laboratory will become the first polarized proton collider. The status of the accelerator and experiments is briefly overviewed. Among various measurements with polarized pp collisions, a study of spin-flavor structure of the nucleon with W production is discussed.

Monte Carlo simulation of vector boson production in polarized proton collisions

We present a Monte Carlo (MC) study of ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and ${Z}_{0}$ production of longitudinally polarized proton collisions at a center of mass (c.m.s.) energy of 500 GeV. All results were obtained with the SPHINX MC code. We consider two different types of polarized parton distributions with large and small gluon polarization. Various spin asymmetries are found to be sensitive to the shape of the polarized gluon distribution between $0.05\ensuremath{\lesssim}x\ensuremath{\lesssim}0.5.$ The asymmetries are approximately constant with respect to the transverse momentum carried by the ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and ${Z}_{0},$ except if the first moment of the gluon polarization is large. In this case some ${W}^{+}$ asymmetries show a significant variation with transverse momentum.