Gell-Mann–Nishijima formula

The Gell-Mann - Nishijima formula ( according to Murray Gell-Mann and Kazuhiko Nishijima, also NNG formula for Nishijima, Nakano, Gell-Mann ) relates the electric charge of an elementary particle ( in units of the elementary charge ) with three of its quantum numbers, namely the third component ( projection ) of the isotopic spin, the baryon number and strangeness:

Here is the hypercharge.

Originally based the formula on experimental results, today it is understood in the context of the quark model. In its above-mentioned simple form it takes into account only the light quarks u, d and s

Extension to heavy quarks

In order to account for the heavy quarks c, b and t, the formula is to expand even to their quantum numbers charm, bottom and Ness Topness:

Thus, the hypercharge is to

Expanded.