Structure Functions of Unstable Lithium Isotopes

Abstract

We study both the spin-average and spin-dependent structure functions of the lithium isotopes, $^{6-11}$Li, which could be measured at RIKEN and other nuclear facilities in the future. It is found that the light-cone momentum distribution of the valence neutron in the halo of $^{11}$Li is very sharp and symmetric around y = 1, because of the weak binding. The EMC ratios for Li isotopes are then calculated. We study the possibility of extracting the neutron structure function from data for the nuclear structure functions of the Li isotopes. Next we calculate the spin-dependent structure functions of $^{7,9,11}$Li isotopes, which have spin of 3/2. The effect of the nuclear binding and Fermi motion on the multipole spin structure function, $^{3/2}_{~1}g_1$, is about 10% in the region x < 0.7, but it becomes quite important at large x. The spin structure function of $^{3/2}_{~3}g_1$ is also investigated. Finally, we discuss the modification of the Gottfried and Bjorken integrals in a nuclear medium and point out several candidates for a pair of mirror nuclei to study the flavor-nonsinglet quark distributions in nuclei.