Higgs field
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| Higgs field | |
|---|---|
| Name | Higgs field |
| Type | Quantum field |
| Discovered | 1964 |
| Theorists | Peter Higgs, François Englert, Robert Brout, Gerald Guralnik, C. R. Hagen, Tom Kibble |
| Confirmed | 2012 |
| Confirmed by | ATLAS experiment, CMS experiment, Large Hadron Collider |
| Related | Higgs boson, Standard Model, Electroweak interaction |
Higgs field The Higgs field is a quantum field in particle physics postulated to explain the origin of mass for elementary particles within the Standard Model. Conceived in the 1960s by theorists working on spontaneous symmetry breaking, the field's nonzero vacuum expectation value gives masses to the W boson, Z boson, and charged fermions, while preserving gauge invariance. Evidence for the associated quantum excitation, the Higgs boson, was reported by the ATLAS experiment and the CMS experiment at the Large Hadron Collider in 2012.
Overview
The Higgs field is a scalar field introduced into the Standard Model to implement the Brout–Englert–Higgs mechanism of spontaneous symmetry breaking. The field transforms under the SU(2)×U(1) gauge symmetry of the electroweak interaction, selecting a vacuum that breaks the symmetry down to U(1). Its presence explains the observed masses of the W boson and Z boson while leaving the photon massless, consistent with electroweak precision tests performed by collaborations at facilities such as LEP and the Tevatron. The field couples to fermions via Yukawa interactions, assigning distinct masses to charged leptons and quarks, in agreement with measurements by experiments including BaBar, Belle, LHCb, and others.
Theoretical framework
In the formalism of quantum field theory developed by groups around Cambridge University, Imperial College London, and institutions such as CERN and Fermilab, the Higgs field is modeled as a complex scalar doublet under SU(2) with a potential exhibiting a Mexican-hat shape. Early papers by Peter Higgs, François Englert, and Robert Brout and parallel works by Gerald Guralnik, C. R. Hagen, and Tom Kibble provided the theoretical underpinnings. The renormalizable Lagrangian couples the field to gauge bosons of SU(2) and U(1) and to fermions through Yukawa terms, treated in perturbation theory alongside radiative corrections computed using techniques developed by researchers connected to Princeton University, SLAC, and the Institute for Advanced Study. Theoretical tools such as the Renormalization group, Spontaneous symmetry breaking, and Goldstone theorem are central; the would-be Goldstone bosons are absorbed into longitudinal modes of the massive gauge bosons in the context of the Higgs mechanism.
Higgs mechanism and mass generation
The Higgs mechanism furnishes masses for gauge bosons without explicit gauge symmetry breaking, a solution crucial to the electroweak unification pursued by scientists at CERN and institutes worldwide. The nonzero vacuum expectation value v ≈ 246 GeV emerges from minimization of the Higgs potential introduced in seminal work by Higgs and others; this scale determines the masses m_W and m_Z measured by collaborations at LEP, SLC, and the Tevatron. Fermion masses arise from Yukawa couplings whose flavor structure connects to flavor physics programs at KEK and SLAC National Accelerator Laboratory. Loop corrections to masses and couplings involve contributions studied in the context of precision electroweak fits by groups such as the Particle Data Group, and tensions motivate searches for physics beyond the Standard Model at initiatives like the International Linear Collider and the Future Circular Collider proposals.
Experimental discovery and measurements
The discovery of a Higgs-like boson was announced by ATLAS experiment and CMS experiment at CERN after analyses of proton–proton collision data from the Large Hadron Collider. The particle's mass near 125 GeV was established through decay channels including γγ, ZZ*, and WW*, with subsequent measurements of couplings to top quark via production in association with top pairs by ATLAS, CMS, and analyses cross-checked with results from Tevatron collaborations CDF and DØ. Precision determinations of signal strengths, spin-parity properties, and rare decays rely on global fits involving the Particle Data Group and combined efforts across experiments such as LHCb. Ongoing programs at CERN and plans for future machines at institutions like DESY aim to refine measurements of self-coupling and total width to test the Higgs sector against theoretical predictions.
Extensions and alternatives
Because the observed Higgs properties leave open questions about naturalness and the hierarchy problem, many extensions have been proposed and tested by collaborations at CERN, Fermilab, KEK, and universities worldwide. Supersymmetric frameworks like the Minimal Supersymmetric Standard Model introduce additional Higgs doublets and predict scalar partners; composite Higgs scenarios from groups influenced by research at SLAC and MIT posit a bound-state origin analogous to pions in QCD studied at Brookhaven National Laboratory. Other proposals include two-Higgs-doublet models explored by theorists affiliated with Princeton University and Harvard University, singlet-extended sectors motivated by dark matter searches at experiments like XENON1T and LUX–ZEPLIN, and extra-dimensional constructions tied to work at Caltech and University of Chicago. Collider searches and flavor constraints from Belle II and LHCb continue to narrow viable parameter space.
Cosmological and astrophysical implications
The Higgs field influences early-universe dynamics studied in cosmology groups at Cambridge University, University of Oxford, and University of California, Berkeley. Its potential affects scenarios of electroweak baryogenesis investigated by researchers connected to CERN and Perimeter Institute, and vacuum stability analyses—using inputs from Planck satellite cosmological parameters and WMAP results—assess whether our vacuum is metastable on cosmological timescales. Interplay with inflationary models proposed by theorists at Stanford University and Columbia University links Higgs dynamics to reheating and primordial perturbations constrained by BICEP and Planck. Astrophysical limits from stellar evolution studies and supernova observations by teams at Max Planck Institute for Astrophysics and NASA provide complementary tests of couplings to light particles and potential portals to hidden sectors.