γ-Z interferometry at a Φ-factory Original Research Article

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 ϱπ channel, taking advantage of the presence of the nearby α1 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 ϱ, to be seen from the angular distribution of its ππ decay products. With polarized electrons a left-right asymmetry around 2 x 10−4 is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the Z0-ss vector coupling. In the ϱπ channel, a combined left-right forward-backward asymmetry is considered.