Optimal spin-quantization axes for the polarization of dileptons with large transverse momentum

The leading-order parton processes that produce a dilepton with large transverse momentum predict that the transverse polarization should increase with the transverse momentum for almost any choice of the quantization axis for the spin of the virtual photon. The rate of approach to complete transverse polarization depends on the choice of spin quantization axis. We propose axes that optimize that rate of approach. They are determined by the momentum of the dilepton and the direction of the jet that provides most of the balancing transverse momentum.Comment: 4 pages, 1 figure, minor corrections, version published in Phys. Rev.

Relativistic Corrections to e+e−→J/ψ+ηce^+e^- \to J/\psi + \eta_c in a Potential Model

We compute relativistic corrections to the process $e^+e^- \to J/\psi + \eta_c$ and find that they resolve the discrepancy between theory and experiment.Comment: 3 pages, talk given at Quark Confinement and the Hadron Spectrum VII, Ponta Delgada, Azores, 2--7 Sept, 200