weakscale

Weakscale refers to the characteristic energy scale of the electroweak interaction in particle physics. It is the regime where the W and Z gauge bosons, the Higgs field and the fermions acquire their masses through electroweak symmetry breaking. The weak scale is commonly associated with the Higgs vacuum expectation value, v ≈ 246 GeV, and with the masses of the W and Z bosons (m_W ≈ 80 GeV, m_Z ≈ 91 GeV). In practice, the weak scale is of order 100 GeV to a few hundred GeV. Below this scale, weak interactions can be described by the Fermi coupling, with G_F ≈ 1.166×10^-5 GeV^-2; at energies near or above the scale, the full electroweak gauge structure with W and Z bosons must be treated explicitly.

The weak scale arises from the Higgs mechanism, in which the SU(2)_L×U(1)_Y gauge symmetry is spontaneously broken to U(1)_em, giving masses to W and Z bosons and to fermions via Yukawa couplings to the Higgs field. The scale is central to discussions of naturalness and the hierarchy problem: why the weak scale is so much smaller than the Planck scale or other high-energy scales without fine-tuning. The weak scale also guides experimental searches and precision tests, with measurements at LEP, SLD, the Tevatron, and the Large Hadron Collider probing processes at energies around this regime. The Higgs boson mass discovered near 125 GeV sits at the lower end of the historically defined weak-scale range.