$γ$ - Z interferometry at a $Φ$-factory
arXiv:hep-ph/9512424 · doi:10.1016/0550-3213(96)00227-1
Abstract
We analyze the possibilities that the proposed $Φ$-factories offer to measure $γ-Z$ interference. In the unpolarized beam case, we study different signatures in the $ÏÏ$ channel, taking advantage of the presence of the near-by $a_1$ resonance. We build a C-odd forward-backward asymmetry, estimated to be around $10^{-5}$, and (P-even, T-even) and (P-odd, T-odd) alignments of the $Ï$, to be seen from the angular distribution of its $ÏÏ$ decay products. With polarized electrons a left-right asymmetry around $2\times 10^{-4}$ is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the $Z^0-s\bar{s}$ vector coupling. In the $ÏÏ$ channel, a combined left-right forward-backward asymmetry is considered.
29 pages + 6 figures. Some changes concerning $a_1$ observables, especially related with possible 2 $γ$ contributions