Angular dependences in electroweak semi-inclusive leptoproduction

Abstract

We present the leading order unpolarized and polarized cross sections in electroweak semi-inclusive deep inelastic leptoproduction. The azimuthal dependences in the cross section differential in the transverse momentum of the vector boson arise due to intrinsic transverse momenta of the quarks. However, the presented asymmetries are not suppressed by inverse powers of the hard scale. We discuss the different opportunities to measure specific asymmetries as offered by neutral compared to charged current processes and point out the optimal kinematical regions. The present and (proposed) future HERA collider experiments would be most suitable for measuring some of the asymmetries discussed here, especially in case of Lambda production.

Figures (3)

• Figure 1: Kinematics for one-particle inclusive leptoproduction. The lepton scattering plane is determined by the momenta $l$, $l^\prime$ and $P$. The azimuthal out-of-plane angle $\phi$ of the produced hadron is indicated.
• Figure 2: The couplings $K_i^{u}(y,Q^2)$ for three different fixed values of $y$: $y=0.4$ solid line, $y=0.6$ dashed line, and $y=0.8$ dotted line. On the left: sum of couplings for $\lambda_e=+1$ and $\lambda_e=-1$ (unpolarized beam). On the right: difference of couplings for $\lambda_e=+1$ and $\lambda_e=-1$ (polarized beam).
• Figure 3: The couplings $K_i^{d}(y,Q^2)$ for three different fixed values of $y$: $y=0.4$ solid line, $y=0.6$ dashed line, and $y=0.8$ dotted line. On the left: sum of couplings for $\lambda_e=+1$ and $\lambda_e=-1$ (unpolarized beam). On the right: difference of couplings for $\lambda_e=+1$ and $\lambda_e=-1$ (polarized beam).