Question

explain in detail about symmetries used in higgs boson? also explain guage boson and guage theory in detail with examples?

Answer 1

SYMMETRY USED IN HIGS BOSON:

To a physicist, symmetry is a broader concept than the reflective form of butterfly wings, or the rotational similarity of a triangular roundabout sign. In physics, to be symmetrical is to be immune to possible changes. Symmetry represents those stub-born cores that remain unaltered even under transformations that could change them.

So far, the particle discovered in July at the LHC looks a lot like the Higgs boson. More tests are needed to prove it. First, the experimentalists must determine the quantum spin of the new boson (the Higgs is predicted to have no spin). Second, they need to measure the rates at which it decays into other particles and compare those to theoretical expectations. Even if the boson passes these tests, symmetry and its breaking do not leave centre stage. One of the major steps beyond the standard model involves supersymmetry the idea that each particle we know has a not-yet-discovered superpartner, with a spin removed by half a quantum-mechanical unit.

Supersymmetry is manifestly broken; other-wise the superpartners would have had the same masses and charges as the known par-ticles and would have been detected already. A broken supersymmetry opens the door to a host of other potential bizarre processes, such as an electron transforming into a muon.There are no signs as yet from the LHC of supersymmetric particles, but this could change. Although the simplest versions of supersymmetry seem to have been ruled out, no one knows what to expect when the LHC increases its energy in two years. Of course, the ultimate goal remains an all-embracing theory that will unify gravity with the other interactions. We still do not know if the underlying principle of such a theory is symmetry, but a confirmation of the newfound boson as the Higgs will show, once again, that symmetry is a guiding light through nature’s labyrinth.

Gauge Boson:

Gauge boson is a force carrier, a bosonic particle that carries any of the fundamental interactions of nature, commonly called forces. Elementary particles, whose interactions are described by a gauge theory, interact with each other by the exchange of gauge bosons usually as virtual particles.

Gauge Theory:

A gauge theory is a type of theory in physics. The word gauge means a measurement, a thickness, an in-between distance (as in railroad tracks), or a resulting number of units per certain parameter (a number of loops in an inch of fabric or a number of lead balls in a pound of ammunition). Modern theories describe physical forces in terms of fields, e.g., the electromagnetic field, the gravitational field, and fields that describe forces between the elementary particles. A general feature of these field theories is that the fundamental fields cannot be directly measured; however, some associated quantities can be measured, such as charges, energies, and velocities. For example, say you cannot measure the diameter of a lead ball, but you can determine how many lead balls, which are equal in every way, are required to make a pound. Using the number of balls, the elemental mass of lead, and the formula for calculating the volume of a sphere from its diameter, one could indirectly determine the diameter of a single lead ball. In field theories, different configurations of the unobservable fields can result in identical observable quantities. A transformation from one such field configuration to another is called a gauge transformation; the lack of change in the measurable quantities, despite the field being transformed, is a property called gauge invariance. For example, if you could measure the color of lead balls and discover that when you change the color, you still fit the same number of balls in a pound, the property of "color" would show gauge invariance. Since any kind of invariance under a field transformation is considered a symmetry, gauge invariance is sometimes called gauge symmetry. Generally, any theory that has the property of gauge invariance is considered a gauge theory.

Explaining Gauge Theory using example :