Heavy Fermion Non-Decoupling Effects in Triple Gauge Boson Vertices

Understand

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.