The Colt line now includes a new scattergun, the Standard or Custom Pump Model ( about $90 and $150, respectively ) in 12, 16 and 20.

* Alain Connes ' Standard Model

Dark energy in its simplest formulation takes the form of the cosmological constant term in Einstein's field equations of general relativity, but its composition and mechanism are unknown and, more generally, the details of its equation of state and relationship with the Standard Model of particle physics continue to be investigated both observationally and theoretically.

Precise modern models of the Big Bang appeal to various exotic physical phenomena that have not been observed in terrestrial laboratory experiments or incorporated into the Standard Model of particle physics.

Within the prevailing Standard Model of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed under experiment.

In the 1950s – 1970s, Caltech was the home of Murray Gell-Mann and Richard Feynman, whose work was central to the establishment of the Standard Model of particle physics.

* Conservation of lepton number ( In the Standard Model )

In the Standard Model, the

The Standard Model of elementary particles, with the fermions in the first three columns and the gauge bosons in the fourth column.

Standard Model of elementary particles

In the Standard Model of particle physics, the elementary particles include the fundamental fermions ( including quarks, leptons, and their antiparticles ), and the fundamental bosons ( including gauge bosons and the Higgs boson ).

According to the Standard Model, all elementary particles are either bosons or fermions ( depending on their spin ).

Such particles lie beyond the Standard Model.

The Standard Model of particle physics contains 12 flavors of elementary fermions, plus their corresponding antiparticles, as well as elementary bosons that mediate the forces and the Higgs boson, which was reported on July 4th, 2012, as having been likely detected by the two main experiments at the LHC ( ATLAS and CMS ).

However, the Standard Model is widely considered to be a provisional theory rather than a truly fundamental one, since it is not known if it is compatible with Einstein's general relativity.

There may be hypothetical elementary particles not described by the Standard Model, such as the graviton, the particle that would carry the gravitational force, and sparticles, supersymmetric partners of the ordinary particles.

The Standard Model recognizes two types of elementary fermions: quarks and leptons.

Gravitons are postulated because of the great success of quantum field theory ( in particular, the Standard Model ) at modeling the behavior of all other known forces of nature as being mediated by elementary particles: electromagnetism by the photon, the strong interaction by the gluons, and the weak interaction by the W and Z bosons.

In contrast, the Standard Model is not background independent, with Minkowski space enjoying a special status as the fixed background space-time.

Attempts to extend the Standard Model or other quantum field theories by adding gravitons run into serious theoretical difficulties at high energies ( processes involving energies close to or above the Planck scale ) because of infinities arising due to quantum effects ( in technical terms, gravitation is nonrenormalizable ).

A Grand Unified Theory, ( GUT ), is a model in particle physics in which at high energy, the three gauge interactions of the Standard Model which define the electromagnetic, weak, and strong interactions, are merged into one single interaction characterized by one larger gauge symmetry and thus one unified coupling constant.

In contrast, the experimentally verified Standard Model of particle physics is based on three independent interactions, symmetries and coupling constants.

, all GUT models which aim to be completely realistic are quite complicated, even compared to the Standard Model, because they need to introduce additional fields and interactions, or even additional dimensions of space.

The fact that the electric charges of electrons and protons seem to cancel each other exactly to extreme precision is essential for the existence of the macroscopic world as we know it, but this important property of elementary particles is not explained in the Standard Model of particle physics.

Hence a measurement of any dramatic change to the H → γγ cross section predicted by the Standard Model is crucial in probing the physics beyond it.

* The group U ( 1 )× SU ( 2 )× SU ( 3 ) is a Lie group of dimension 1 + 3 + 8 = 12 that is the gauge group of the Standard Model in particle physics.

* Standard Model, the theory in particle physics which describes certain fundamental forces and particles

In the Standard Model of particle physics, this symmetry is described as arising as a consequence of a coupling of particles with rest mass to a postulated additional field, known as the Higgs field.

On the other hand, the Standard Model of Particle physics uses quantum field theory to describe all interactions.

Lie groups are the symmetry groups used in the Standard Model of particle physics ; Point groups are used to help understand symmetry phenomena in molecular chemistry ; and Poincaré groups can express the physical symmetry underlying special relativity.

( The Standard Model of particle physics had assumed that neutrinos are massless and cannot change flavor.

The current set of fundamental fields and their dynamics are summarized in a theory called the Standard Model, therefore particle physics is largely the study of the Standard Model's particle content and its possible extensions.

In the Standard Model of particle physics, photons are described as a necessary consequence of physical laws having a certain symmetry at every point in spacetime.

Quarks are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactions, also known as fundamental forces ( electromagnetism, gravitation, strong interaction, and weak interaction ), as well as the only known particles whose electric charges are not integer multiples of the elementary charge.

The theory is an important part of the Standard Model of particle physics.

Most theories in modern particle physics, including the Standard Model of elementary particles and their interactions, are formulated as relativistic quantum field theories.

Interaction in the subatomic world: world line s of point-like Subatomic particle | particle s in the Standard Model or a world sheet swept up by closed string ( physics ) | strings in string theory

Interaction in the subatomic world: world line s of point-like Subatomic particle | particle s in the Standard Model or a world sheet swept up by closed string ( physics ) | strings in string theory

* Standard Reduction potential, a measure of the tendency of a chemical species to acquire electrons and thereby be reduced

According to the Standard Model of particle physics, the particles that make up an atom — quarks and electrons — are point particles: they do not take up space.

* Quarks appear to be point charges, as electrons appear to be, with the fractional charges suggested by the Standard Model.