Jacques Soffer

POSITIVITY CONSTRAINTS FOR SPIN-DEPENDENT PARTON DISTRIBUTIONS

We derive new positivity constraints on the spin-dependent structure functions of the nucleon. These model-independent results reduce considerably their domain of allowed values, in particular, for the chiral-odd parton distribution [ital h][sub 1]([ital x]).

PROSPECTS FOR SPIN PHYSICS AT RHIC

▪ Abstract Colliding beams of 70% polarized protons at up to GeV, with high luminosity, L = 2 × 1032 cm−2 sec−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 , 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.

A statistical approach for polarized parton distributions

Abstract. A global next-to-leading order QCD analysis of unpolarized and polarized deep-inelastic scattering data is performed with parton distributions constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is also emphasized. We obtain a good description, in a broad range of x and

Impact-picture expectations for very high-energy elastic pp and pp scattering

Q^2

Impact-picture phenomenology for

, of all measured structure functions in terms of very few free parameters. We stress the fact that at RHIC-BNL the ratio of the unpolarized cross sections for the production of

\pi^{\pm}p,~K^{\pm}p

W^+

and

and

pp,~\bar p p

W^-

elastic scattering at high energies

in

Parton distributions and parity-violating asymmetries in W± and Z production at RHIC

pp