Unitarity and nonperturbative effects in the spin structure functions at small $x$

Abstract

We consider low-$x$ behavior of the spin structure functions $g_1(x)$ and $h_1(x)$ in the unitarized chiral quark model that combines the ideas on constituent quark structure of hadrons with a geometrical scattering picture and unitarity. A nondiffractive singular low-$x$ dependence of $g_1^p(x)$ and $g_1^n(x)$ is obtained and a diffractive type smooth behavior of $h_1(x)$ is predicted at small $x$.

Comments: 4 pages, 1 figure, talk given by S. Troshin at the DESY Workshop: Polarized Protons at High Energies - Accelerator Challenges and Physics Opportunities, Hamburg 17-20 May 1999