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SO(10) (physics)
In particle physics, SO(10) refers to a grand unified theory (GUT) based on the spin group Spin(10). The shortened name SO(10) is conventional among physicists, and derives from the Lie algebra or less precisely the Lie group of SO(10), which is a special orthogonal group that is double covered by Spin(10). SO(10) subsumes the Georgi–Glashow and Pati–Salam models, and unifies all fermions in a generation into a single field. This requires 12 new gauge bosons, in addition to the 12 of SU(5) and 9 of SU(4)×SU(2)×SU(2). History Before the SU(5) theory behind the Georgi–Glashow model, Harald Fritzsch and Peter Minkowski, and independently Howard Georgi, found that all the matter contents are incorporated into a single representation, spinorial 16 of SO(10). However, it is worth noting that Georgi found the SO(10) theory just a few hours before finding SU(5) at the end of 1973. Important subgroups It has the branching rules to U(5)×U(1)χZ5. : 45 \ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SO10
SO10 was the former designation of the Metropolitan Police's Covert Operations Group. History The group's origins can be traced back to 1960, with the formation of what was known as the Criminal Investigation Branch, which later evolved and was merged into SO10 and the Public Order Unit. The group's original name referred to its Specialist Operations designation prior to restructuring of the Metropolitan Police, which saw it re- designated to the Specialist Crime Directorate as SCD10, though it is still colloquially referred to as SO10. Role The group's role is to provide specially trained officers and resources for cases requiring covert policing and evidence gathering. It had responsibility for all undercover policing in London, particularly focusing on surveillance and relying on support from armed officers and specialist surveillance photography. Some of their most notable work is that in counter-terrorism operations, the most high profile of which led to the shooting of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Minkowski
Peter Minkowski (born 10 May 1941) is a Swiss theoretical physicist. He is primarily known for his proposal, with Harald Fritzsch, of SO(10) as the group of a grand unified theory and for his independent proposal, more-or-less simultaneously with a number of other theorists, of the seesaw mechanism for the generation of neutrino masses. Biography Peter Minkowski, a life-long Swiss citizen, is the son of Mieczyslaw, a neurologist, and Irene Minkowski-Fux, a painter and architect. After his Abitur at Realgymnasium Zurich and his physics Diploma in 1963 from the Federal Institute of Technology in Zurich (ETHZ), he earned his Ph.D. in 1967 at ETHZ under Markus Fierz with thesis ''Versuch einer konsistenten Theorie eines Spin-2-Mesons'' ("Attempt at a Consistent Theory of a Spin 2 Meson"). In 1967–1969 Minkowski was an assistant at the Institute for Theoretical Physics, University of Louvain in Belgium, in 1969–1971 research associate of the Swiss Institute for Nuclear Research (S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left-right Model
A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called parity transformation. Invariance under parity transformation by a Dirac fermion is called chiral symmetry. Chirality and helicity The helicity of a particle is positive (“right-handed”) if the direction of its spin is the same as the direction of its motion. It is negative (“left-handed”) if the directions of spin and motion are opposite. So a standard clock, with its spin vector defined by the rotation of its hands, has left-handed helicity if tossed with its face directed forwards. Mathematically, ''helicity'' is the sign of the projection of the spin vector onto the momentum vector: “left” is negative, “right” is positive. The chirality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left-right Symmetry
A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called parity transformation. Invariance under parity transformation by a Dirac fermion is called chiral symmetry. Chirality and helicity The helicity of a particle is positive (“right-handed”) if the direction of its spin is the same as the direction of its motion. It is negative (“left-handed”) if the directions of spin and motion are opposite. So a standard clock, with its spin vector defined by the rotation of its hands, has left-handed helicity if tossed with its face directed forwards. Mathematically, ''helicity'' is the sign of the projection of the spin vector onto the momentum vector: “left” is negative, “right” is positive. The chirality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flipped SU(5)
The Flipped SU(5) model is a grand unified theory (GUT) first contemplated by Stephen Barr in 1982, and by Dimitri Nanopoulos and others in 1984. Ignatios Antoniadis, John Ellis, John Hagelin, and Dimitri Nanopoulos developed the supersymmetric flipped SU(5), derived from the deeper-level superstring. Some current efforts to explain the theoretical underpinnings for observed neutrino masses are being developed in the context of supersymmetric flipped . Flipped is not a fully unified model, because the factor of the Standard Model gauge group is within the factor of the GUT group. The addition of states below ''M''x in this model, while solving certain threshold correction issues in string theory, makes the model merely descriptive, rather than predictive. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yukawa Coupling
In particle physics, Yukawa's interaction or Yukawa coupling, named after Hideki Yukawa, is an interaction between particles according to the Yukawa potential. Specifically, it is a scalar field (or pseudoscalar field) and a Dirac field of the type :~ V \approx g \, \bar\psi \, \phi \, \psi \quad (scalar) \qquad or \qquad g \, \bar\psi \, i \,\gamma^5 \, \phi \, \psi \quad ( pseudoscalar). The Yukawa interaction was developed to model the strong force between hadrons. A Yukawa interaction is thus used to describe the nuclear force between nucleons mediated by pions (which are pseudoscalar mesons). A Yukawa interaction is also used in the Standard Model to describe the coupling between the Higgs field and massless quark and lepton fields (i.e., the fundamental fermion particles). Through spontaneous symmetry breaking, these fermions acquire a mass proportional to the vacuum expectation value of the Higgs field. This Higgs-fermion coupling was first described by Steve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Higgs
Peter Ware Higgs (born 29 May 1929) is a British theoretical physicist, Emeritus Professor in the University of Edinburgh,Griggs, Jessica (Summer 2008The Missing Piece ''Edit'' the University of Edinburgh Alumni Magazine, p. 17 and Nobel Prize laureate for his work on the mass of subatomic particles. In the 1960s, Higgs proposed that broken symmetry in electroweak theory could explain the origin of mass of elementary particles in general and of the W and Z bosons in particular. This so-called Higgs mechanism, which was proposed by several physicists besides Higgs at about the same time, predicts the existence of a new particle, the Higgs boson, the detection of which became one of the great goals of physics. On 4 July 2012, CERN announced the discovery of the boson at the Large Hadron Collider. The Higgs mechanism is generally accepted as an important ingredient in the Standard Model of particle physics, without which certain particles would have no mass. Higgs has been honour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauge Symmetry
In physics, a gauge theory is a type of field theory in which the Lagrangian (and hence the dynamics of the system itself) does not change (is invariant) under local transformations according to certain smooth families of operations (Lie groups). The term ''gauge'' refers to any specific mathematical formalism to regulate redundant degrees of freedom in the Lagrangian of a physical system. The transformations between possible gauges, called ''gauge transformations'', form a Lie group—referred to as the ''symmetry group'' or the ''gauge group'' of the theory. Associated with any Lie group is the Lie algebra of group generators. For each group generator there necessarily arises a corresponding field (usually a vector field) called the ''gauge field''. Gauge fields are included in the Lagrangian to ensure its invariance under the local group transformations (called ''gauge invariance''). When such a theory is quantized, the quanta of the gauge fields are called ''gauge boson ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renormalizable
Renormalization is a collection of techniques in quantum field theory, the statistical mechanics of fields, and the theory of self-similar geometric structures, that are used to treat infinities arising in calculated quantities by altering values of these quantities to compensate for effects of their self-interactions. But even if no infinities arose in loop diagrams in quantum field theory, it could be shown that it would be necessary to renormalize the mass and fields appearing in the original Lagrangian. For example, an electron theory may begin by postulating an electron with an initial mass and charge. In quantum field theory a cloud of virtual particles, such as photons, positrons, and others surrounds and interacts with the initial electron. Accounting for the interactions of the surrounding particles (e.g. collisions at different energies) shows that the electron-system behaves as if it had a different mass and charge than initially postulated. Renormalization, in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superpotential
In theoretical physics, the superpotential is a function in supersymmetric quantum mechanics. Given a superpotential, two "partner potentials" are derived that can each serve as a potential in the Schrödinger equation. The partner potentials have the same spectrum, apart from a possible eigenvalue of zero, meaning that the physical systems represented by the two potentials have the same characteristic energies, apart from a possible zero-energy ground state. One-dimensional example Consider a one-dimensional, non-relativistic particle with a two state internal degree of freedom called "spin". (This is not quite the usual notion of spin encountered in nonrelativistic quantum mechanics, because "real" spin applies only to particles in three-dimensional space.) Let ''b'' and its Hermitian adjoint ''b''† signify operators which transform a "spin up" particle into a "spin down" particle and vice versa, respectively. Furthermore, take ''b'' and ''b''† to be normalized such that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypercharge
In particle physics, the hypercharge (a portmanteau of hyperon, hyperonic and charge (physics), charge) ''Y'' of a subatomic particle, particle is a quantum number conserved under the strong interaction. The concept of hypercharge provides a single charge (physics), charge operator that accounts for properties of isospin, electric charge, and flavour (particle physics), flavour. The hypercharge is useful to classify hadrons; the similarly named weak hypercharge has an analogous role in the electroweak interaction. Definition Hypercharge is one of two quantum numbers of the Eightfold way (physics) #SU(3), SU(3) model of hadrons, alongside isospin . The isospin alone was sufficient for two quark flavours — namely and — whereas presently 6 flavour (particle physics), flavours of quarks are known. SU(3) weight diagrams (see below) are 2 dimensional, with the coordinates referring to two quantum numbers: (also known as ), which is the component of isospin, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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