feynlag.pheno.offshell.scalar_offshell_vv_width

feynlag.pheno.offshell.scalar_offshell_vv_width(m_S, m_V, width_V, g_SVV, channels, identical=False, backend='auto')[source]

Γ(S → V V^* → V f f̄') summed over the V^* fermion channels.

Parameters:

  • m_S – parent scalar mass.

  • m_V – vector mass.

  • width_V – the vector total width $Gamma_V$ (Breit–Wigner).

  • g_SVV – the SVV coupling (the Feynman rule with its i stripped, e.g. g m_V for hWW).

  • channels – iterable of (g_L, g_R, multiplicity) for each distinct V^*→f f̄' fermion channel — g_L, g_R the chiral couplings of the V f f̄' current, multiplicity a colour/flavour count.

  • identical – False for S→V₁V₂* with distinct vectors (e.g. WW: either W⁺ or W⁻ is the on-shell one → an overall factor 2); True for identical vectors (ZZ: no factor 2).

Returns:

the total off-shell width (float). Reproduces the Keung–Marciano closed form (Γ(h→WW*)≈0.80 MeV, Γ(h→ZZ*)≈0.089 MeV).