Leading asymmetries in two-hadron production in e^+e^- annihilation at the Z pole

Abstract

We present the leading unpolarized and single spin asymmetries in inclusive two-hadron production in electron-positron annihilation at the Z pole. The azimuthal dependence in the unpolarized differential cross section of almost back-to-back hadrons is a leading cos(2 phi) asymmetry, which arises solely due to the intrinsic transverse momenta of the quarks. An extensive discussion on how to measure this asymmetry and the accompanying time-reversal odd fragmentation functions is given. A simple estimate indicates that the asymmetry could be of the order of a percent.

Figures (2)

• Figure 1: Kinematics of the annihilation process in the lepton center of mass frame for a back-to-back jet situation. $P_1$ ($P_2$) is the momentum of a fast hadron in jet one (two).
• Figure 2: Factor defined in Eq. (\ref{['factor']}) depending on the center of mass angle $\theta_2$.