Nuclear effects in g_1A (x,Q²) at small x in deep inelastic scattering on ⁷Li and ³He

We suggest using polarized nuclear targets of ⁷Li and ³He to study nuclear effects in the spin-dependent structure functions g_1A(x,Q²). These effects are expected to be enhanced by a factor of 2 as compared to the unpolarized targets. We predict a significant x dependence at 10^-4-10^-3 ≤x≤ 0.2 of g_1A(x,Q²)/ g_1N(x,Q²) due to nuclear shadowing and nuclear enhancement. The effect of nuclear shadowing at x ≈ 10^-3 is of an order of 16% for g^{n.s, 3/2}_{1A = 7} (x,Q²)/ g^n.s._1N (x,Q²) and 10% for g^n.s_{1A = 3} (x,Q²)/ g^n.s._1N (x,Q²). By imposing the requirement that the Bjorken sum rule is satisfied we model the effect of enhancement. We find the effect of enhancement at x ≈ 0.125 (0.15) to be of an order of 20 (55)% for g^{n.s 3/2}_{1A = 7} (x,Q²)/ g^n.s._1N (x,Q²) and 14 (40)% for g^n.s_{1A = 3} (x,Q²)/ g^n.s._1N (x,Q²), if enhancement occupies the region 0.05 ≤ x ≤ 0.2 (0.1 ≤ x ≤ 0.2). We predict a 2% effect in the difference of the scattering cross sections of deep inelastic scattering of an unpolarized projectile off ⁷Li with M_J = 3/2 and M_J = 1/2. We also show explicitly that the many-nucleon description of deep inelastic scattering off ⁷Li becomes invalid in the enhancement region 0.05 < x ≤ 0.2.