X (charge)

Flavour in particle physics
Flavour quantum numbers
Isospin: I or I₃ Charm: C Strangeness: S Topness: T Bottomness: B′
Related quantum numbers
Baryon number: B Lepton number: L Weak isospin: T or T₃ Electric charge: Q X-charge: X
Combinations
Hypercharge: Y Y = (B + S + C + B′ + T) Y = 2 (Q − I₃) Weak hypercharge: Y_W Y_W = 2 (Q − T₃) X + 2Y_W = 5 (B − L)
Flavour mixing
CKM matrix PMNS matrix Flavour complementarity

In particle physics, the X-charge (or simply X) is a conserved quantum number associated with the SO(10) grand unification theory.

X is related to the difference between the baryon number B and the lepton number L (that is B − L), and the weak hypercharge Y_W via the relation:

X = 5(B - L) - 2Y_W \,

See also