A_LR is an important input for EFT analysis. Radiative Z return events are useful for energy calibration.Physics Motivation: this process is directly related to contact interaction e-e-Z-H-H, left and right asymmetry (via cross section measurements for polarized beams) can provide a very strong constraints. Current best precision from SLD is still very limited.
Search Channel: e+e- → gamma Z, Z→ll/qq, Ecm=500 GeV.
Detector Benchmark: thanks to the known central value of gamma energy / Z invariant mass; calibrate jet energy scale, calibrate lepton momentum scale, calibrate photon energy scale (though only at one energy). Isolated photon/lepton reconstruction/tagging efficiencies, jet/photon energy resolution.
final observable: A_LR , total x-section, JER, JES, M_Z, E_gammafor cross section of e+e- → gamma Z.
intermediate observables: lepton/photon reconstruction efficiencies, momentum/energy resolution/scale, JER/JES.
Kazuki Fujii, “h->gamma Z”, [XYZ0218]