= Relativistic entropy content of the Standard Model
{title2=$g_{*s}^{\mathrm{SM}}=28+\frac78\,90=106.75$}
In the ideal-gas high-temperature limit, the <Standard Model> has 28 <boson> states: 16 <gluon> states, eight electroweak <gauge boson> states and four <Higgs field> states. Its 90 <fermion> states are 72 <quark> states, 12 charged <lepton> states and six <neutrino> states. Counting a relativistic <fermion> state with weight $7/8$ gives the displayed <effective number of relativistic entropy degrees of freedom>. The <effective number of relativistic energy degrees of freedom> has the same value when all species share a temperature. Mass thresholds and interactions change the ideal-gas count.
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