= Higgs branching-fraction normalization from mass-weighted channels
{c}
{title2=$B_f=B_{\cal S}N_c^fm_f^2/\sum_{j\in\cal S}N_c^jm_j^2$}
At leading order, neglecting phase-space suppression and radiative corrections, <Higgs decay to a fermion pair> has partial <decay width> proportional to $N_c^fm_f^2$, with $N_c=3$ for a quark and one for a lepton. A known sum of <branching fractions> therefore fixes the proportionality between these weights and individual branching fractions without requiring the Higgs vacuum expectation value. The same normalization estimates a small additional fermionic channel if its weight is not included in the known sum.
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