Speaker
Description
It is well known that the back-to-back correlation limit of inclusive quark-antiquark dijet production in unpolarized high energy electron-proton collisions can probe the Weizsacker-Williams (WW) gluon distribution at small x. In this talk, we consider double-spin asymmetry for inclusive quark-antiquark dijet production in longitudinally polarized electron proton/nucleus scatterings at high energies. It is shown that in the back-to-back correlation limit, this process uniquely probes the WW gluon helicity distribution. Furthermore, we derive the small-x evolution equation for WW gluon helicity distribution using an operator method. It is found that in the double-logarithmic approximation and in the large-$N_c$ limit, the small-x evolution equation for WW gluon helicity distribution is the same as that for the dipole gluon helicity distribution. The longitudinal double-spin asymmetry for inclusive dijet production can thus facilitate constraining the initial conditions for small-x helicity evolution equations in the upcoming EIC.
