Electroweak symmetry breaking

Electroweak symmetry breaking is the Higgs field’s nonzero vacuum value distinguishing the electromagnetic and weak interactions. It gives the W and Z bosons mass while leaving the photon massless.

Higgs field: A quantum field whose nonzero vacuum value gives mass to elementary particles through their interactions with it. Its nonzero vacuum value drives the symmetry breaking.
Electroweak interaction: The unified description of electromagnetic and weak interactions at high energies. It is the unified interaction whose low-energy forms become distinct.
François Englert: A Belgian theoretical physicist who co-developed a mechanism for generating gauge-boson masses. His 1964 work helped establish the field-based mechanism.
Fermion mass: The mass of a spin-one-half particle, such as a quark or charged lepton. Fermion masses arise through their couplings to the Higgs field.
Higgs self-coupling: The strength of interactions among Higgs bosons, determined by the Higgs potential. Measuring it tests the potential that drives symmetry breaking.
Higgs potential: The energy function of the Higgs field, whose shape favors a nonzero field value in empty space. Its minimum away from zero makes the symmetric vacuum unstable.
Electroweak gauge group: The Standard Model gauge symmetry SU(2)ₗ × U(1)ᵧ underlying electroweak interactions. Its symmetry is reduced to electromagnetic gauge symmetry by the Higgs vacuum.
Robert Brout: A Belgian-American theoretical physicist who co-developed the gauge-boson mass-generation mechanism. His collaboration with Englert produced an early formulation of the mechanism.
CKM matrix: A matrix describing quark flavor mixing in charged weak interactions. Electroweak symmetry breaking turns quark Yukawa couplings into mass-basis mixing.
Higgs hierarchy problem: The puzzle of why the Higgs mass remains far below scales suggested by quantum corrections. It challenges explanations of the Higgs field’s mass and stability.

Linked from 10 pages