The strangeness of a particle is the sum of the strangeness of its component quarks. Of the six flavors of quarks, only the strange quark has a nonzero strangeness. The strangeness of nucleons is zero, because they only contain up and down quarks and no strange (also called sideways) quarks.

What particle has strangeness?

The up and down quarks are distinguished mainly by their differing electric charges, while the heavier quarks each carry a unique quantum number related to their flavour. The strange quark has strangeness, S = −1, the charm quark has charm, C = +1, and so on.

Do leptons have strangeness?

All hadrons which contain an anti-strange quark (��)are assigned a strangeness number S=+1. Leptons, and hadrons which don't contain a strange quark have strangeness S=0.