γ - Z interferometry at a Φ -factory
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
ρπ
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
ρ
, to be seen from the angular distribution of its
ππ
decay products. With polarized electrons a left-right asymmetry around
2×
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
s
¯
vector coupling. In the
ρπ
channel, a combined left-right forward-backward asymmetry is considered.