Athanasios Dedes, Kristaq Suxho
Within a spontaneously broken gauge group we carefully analyse and calculate
triple gauge boson vertices dominated by triangle one-loop Feynman diagrams
involving heavy fermions compared to external momenta and gauge boson masses.
We perform our calculation strictly in four dimensions and derive a general
formula for the off-shell, one-particle irreducible (1PI) effective vertex
which satisfies the relevant Ward Identities and the Goldstone boson
equivalence theorem. Our goal is to search for non-decoupling heavy fermion
effects highlighting their synergy with gauge chiral anomalies. Particularly in
the Standard Model, we find that when the arbitrary anomaly parameters are
fixed by gauge invariance and/or Bose symmetry, the heavy fermion contribution
cancels its anomaly contribution leaving behind anomaly and mass independent
contributions from the light fermions. We apply these results in calculating
the corresponding CP-invariant one-loop induced corrections to triple gauge
boson vertices in the SM, minimal $Z'$models as well as their extensions with a
fourth fermion generation, and compare with experimental data.
View original:
http://arxiv.org/abs/1202.4940
No comments:
Post a Comment