A model for the Q2Q^2 dependence of polarized structure functions

We present an update of a phenomenological model for the spin dependent structure functions $g_1(x,Q^2)$ of the proton and neutron. This model is based on a broken SU(6) wavefunction parametrized by the unpolarized structure functions. The two free parameters of the model are choosen to fulfill the Bjorken and Ellis--Jaffe sum rules. The model respects isospin symmetry and has zero strange sea polarization. Using new values for $F/D$ from hyperon beta decay the resulting $Q^2$ dependent asymmetries $A_1$ are in perfect agreement with the existing data. Therefore we do not see any evidence for a ``spin crisis''. With two choices for $g_2$ the $Q^2$ dependence of $A_1(x,Q^2)$ and $A_2(x,Q^2)\sqrt{Q^2}/M$ is predicted and shown to be small for both cases.Comment: 18 pages and 11 figures as uudecoded ps file

SPIN-DEPENDENT NUCLEAR STRUCTURE FUNCTIONS: GENERAL APPROACH WITH APPLICATION TO THE DEUTERON

We study deep-inelastic scattering from polarized nuclei within a covariant framework. A clear connection is established between relativistic and non-relativistic limits, which enables a rigorous derivation of convolution formulae for the spin-dependent nuclear structure functions g_1^A and g_2^A in terms of off-mass-shell extrapolations of polarized nucleon structure functions, g_1^N and g_2^N. Approximate expressions for g_{1,2}^A are obtained by expanding the off-shell g_{1,2}^N about their on-shell limits. As an application of the formalism we consider nuclear effects in the deuteron, knowledge of which is necessary to obtain accurate information on the spin-dependent structure functions of the neutron.Comment: 26 pages RevTeX, 9 figures available upon reques

Polarized deep-inelastic scattering from nuclei: a relativistic approach.

We discuss spin-dependent, deep-inelastic scattering from nuclei within a covariant framework. In the relativistic impulse approximation this is described in terms of the amplitude for forward, virtual-photon scattering from an off-mass-shell nucleon. The general structure of the off-shell nucleon hadronic tensor is derived, and the leading behavior of the off-shell nucleon structure functions computed in the Bjorken limit. The formalism, which is valid for nucleons bound inside nuclei with spin 1/2 or 1, is applied to the case of the deuteron.Piller, G. ; Melnitchouk, W. ; Thomas, A.W

Analysis of shared heritability in common disorders of the brain

Paroxysmal Cerebral Disorder