particle physics Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...

, the electroweak scale, also known as the Fermi scale, is the

energy scale This list compares various energies in joules (J), organized by order of magnitude. Below 1 J 1 to 105 J 106 to 1011 J 1012 to 1017 J 1018 to 1023 J Over 1024 J SI multiples See also * Conversion of units of e ...

around 246 GeV, a typical

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

of processes described by the

electroweak theory In particle physics, the electroweak interaction or electroweak force is the unified description of two of the fundamental interactions of nature: electromagnetism (electromagnetic interaction) and the weak interaction. Although these two forc ...

. The particular number 246 GeV is taken to be the

vacuum expectation value In quantum field theory, the vacuum expectation value (VEV) of an operator is its average or expectation value in the vacuum. The vacuum expectation value of an operator O is usually denoted by \langle O\rangle. One of the most widely used exa ...

v = (G_F \sqrt)^

of the

Higgs field The Higgs boson, sometimes called the Higgs particle, is an elementary particle in the Standard Model of particle physics produced by the excited state, quantum excitation of the Higgs field, one of the field (physics), fields in particl ...

(where

G_F

is the Fermi coupling constant). In some cases the term ''electroweak scale'' is used to refer to the temperature of electroweak symmetry breaking, 159.5±1.5 GeV . In other cases, the term is used more loosely to refer to energies in a broad range around 10² - 10³ GeV. This is within reach of the

Large Hadron Collider The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the CERN, European Organization for Nuclear Research (CERN) between 1998 and 2008, in collaboration with over 10,000 scientists, ...

(LHC), which is designed for about 10⁴ GeV in proton–proton collisions. Interactions may have been above this scale during the

electroweak epoch In physical cosmology, the electroweak epoch was the period in the evolution of the early universe when the temperature of the universe had fallen enough that the strong force separated from the electronuclear interaction, but was still high en ...

. In the unextended

Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

, the transition from the

was not a first or a second order

phase transition In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic Sta ...

but a continuous crossover, preventing any

baryogenesis In physical cosmology, baryogenesis (also known as baryosynthesis) is the physical process that is hypothesized to have taken place during the early universe to produce baryonic asymmetry, the observation that only matter (baryons) and not anti ...

. However many extensions to the standard model including

supersymmetry Supersymmetry is a Theory, theoretical framework in physics that suggests the existence of a symmetry between Particle physics, particles with integer Spin (physics), spin (''bosons'') and particles with half-integer spin (''fermions''). It propo ...

and the inert double model have a first order electroweak phase transition (but still lack additional

CP violation In particle physics, CP violation is a violation of CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge conjugation symmetry) and P-symmetry ( parity symmetry). CP-symmetry states that the laws of physics s ...

References

Electroweak theory {{particle-stub