Everything about Electroweak totally explained
In
particle physics, the
electroweak interaction is the unified description of two of the four
fundamental interactions of nature:
electromagnetism and the
weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 10
2 GeV, they'd merge into a single
electroweak force. Thus if the universe is hot enough (approximately 10
15 K, a temperature reached shortly after the
Big Bang) then the electromagnetic force and weak force will merge into a combined electroweak force.
For contributions to the unification of the weak and electromagnetic interaction between
elementary particles,
Abdus Salam,
Sheldon Glashow and
Steven Weinberg were awarded the
Nobel Prize in Physics in
1979.
The existence of the electroweak interactions was experimentally established in two stages: the first being the discovery of
neutral currents in neutrino scattering by the
Gargamelle collaboration in 1973, and the second in 1983 by the
UA1 and the
UA2 collaborations that involved the discovery of the
W and Z gauge bosons in proton-antiproton collisions at the converted
Super Proton Synchrotron.
Formulation
Mathematically, the unification is accomplished under an
SU(2) ×
U(1) gauge group. The corresponding gauge
bosons are the
photon of electromagnetism and the
W and Z bosons of the weak force. In the
Standard Model, the weak gauge bosons get their
mass from the
spontaneous symmetry breaking of the
electroweak symmetry from
SU(2) ×
U(1)
Y to
U(1)
em, caused by the
Higgs mechanism (see also
Higgs boson). The subscripts are used to indicate that these are different copies of
U(1); the generator of
U(1)
em is given by
Q =
Y/2 +
I3, where
Y is the generator of
U(1)
Y (called the
weak hypercharge), and
I3 is one of the
SU(2) generators (a component of
weak isospin). The distinction between electromagnetism and the weak force arises because there's a (nontrivial) linear combination of
Y and
I3 that vanishes for the Higgs boson (it is an eigenstate of both
Y and
I3, so the coefficients may be
taken as −
I3 and
Y):
U(1)
em is defined to be the group generated by this linear combination, and is unbroken because it doesn't interact with the Higgs.
Lagrangian
Before Electroweak Symmetry Breaking
The
Lagrangian for the electroweak interactions is divided into four parts before
electroweak symmetry breaking » Further Information
Get more info on 'Electroweak'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://electroweak_interaction.totallyexplained.com">Electroweak interaction Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
