Azimuthal angle dependence of di-jet production in unpolarized hadron scattering

Abstract

We study the azimuthal angular dependence of back-to-back di-jet production in unpolarized hadron scattering $H_A+H_B\to J_1+J_2+X$, arising from the product of two Boer-Mulders functions, which describe the transverse spin distribution of quarks inside an unpolarized hadron. We find that when the di-jet is of two identical quarks ($J_q+J_q$) or a quark-antiquark pair ($J_q+J_{\bar{q}}$), there is a $\cos \hat{I}´\ddot{I}•$ angular dependence of the di-jet, with $\hat{I}´\ddot{I}•=\ddot{I}{•}_1-\ddot{I}{•}_2$, and $\ddot{I}{•}_1$ and $\ddot{I}{•}_2$ are the azimuthal angles of the two individual jets. In the case of $J_q+J_q$ production, we find that there is a color factor enhancement in the gluonic cross-section, compared with the result from the standard generalized parton model. We estimate the $\cos \hat{I}´\ddot{I}•$ asymmetry of di-jet production at RHIC, showing that the color factor enhancement in the angular dependent of $J_q+J_q$ production will reverse the sign of the asymmetry.

10 pages, 7 figures, version accepted by Physical Review D