feynlag.pheno.propagator.propagator_denominator¶

feynlag.pheno.propagator.propagator_denominator(q2, mass, width=0)[source]¶: q² − m² + i m Γ — the single source of truth for both the amplitude-level 1/D propagators below and the squared breit_wigner() line shape (breit_wigner(q2,m,Γ) == 1/(D·conjugate(D)) for real q2, m, Γ).