Weak hypercharge

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Flavour in particle physics v • d • e

Flavour quantum numbers: Lepton number: L Baryon number: B Strangeness: S Charm: C Bottomness: B' Topness: T Isospin: Iz or I Weak isospin: Tz Electric charge: Q Combinations: Hypercharge: Y Y=2(Q-Iz) Weak hypercharge: YW YW=2(Q-Tz) YW=B−L Related topics: CPT symmetry CKM matrix CP symmetry Chirality

The weak hypercharge in particle physics is a quantum number relating the electrical charge and the third component of weak isospin, and is similar to the Gell-Mann–Nishijima formula of strong interactions. It is the generator of the U(1) component of the electroweak gauge group, SU(2)xU(1) and its associated quantum field B mixes with the W³ electroweak quantum field to produce the observed Z⁰ gauge boson and the photon of quantum electrodynamics.

Weak hypercharge, usually written as Y_W, is defined as:

where Q is the electrical charge (in elementary charge units) and T_z is the third component of weak isospin. Rearranging, the weak hypercharge can be expressed as:

[edit] See also

• Field theoretical formulation of the standard model
• Weak isospin