New and standard physics contributions to anomalous Z and gamma self-couplings - art. no. 073013

We examine the standard and the new physics (NP) contributions to the ZZZ, ZZ gamma, and Z gamma gamma neutral gauge couplings. At the one-loop level, if we assume that there is no CP violation contained in NP beyond the stan dard model (SM) one, we find that only CP conserving neutral gauge coupling s are generated, either from the standard quarks and leptons, or from possi ble new physics fermions. Bosonic one-loop diagrams never contribute to the se couplings, while the aforementioned fermionic contributions satisfy h(3) (Z)similar or equal to-f(5)(gamma), h(4)(Z)=h(4)(gamma) =0. We also study e xamples of two-loop NP effects that could generate nonvanishing h(4)(gamma, Z) couplings. We compare quantitative estimates from SM, minimal supersymme tric standard model (MSSM), and some specific examples of NP contributions, and we discuss their observability at future colliders.