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Flipped SO(10)
Flipped SO(10) is a grand unified theory which is to standard SO(10) as flipped SU(5) is to SU(5). Details In conventional SO(10) models, the fermions lie in three spinorial 16 representations, one for each generation, which decomposes under ''SU(5) × U(1)χZ5 as :16 \rightarrow 10_1 \oplus \bar_ \oplus 1_5 This can either be the Georgi–Glashow SU(5) or flipped SU(5). In flipped SO(10) models, however, the gauge group is not just SO(10) but SO(10)F × U(1)B or ''SO(10)F × U(1)BZ4. The fermion fields are now three copies of :16_1\oplus 10_ \oplus 1_4 These contain the Standard Model fermions as well as additional vector fermions with GUT scale masses. If we suppose ''SU(5) × U(1)AZ5 is a subgroup of SO(10)F, then we have the intermediate scale symmetry breaking ''SO(10)F × U(1)BZ4 → ''SU(5) × U(1)χZ5 where :\chi=-+ In that case, :\begin 16_1&\rightarrow 10_1 \oplus \bar_2 \oplus 1_0 \\ 10_&\rightarrow 5_ \oplus \bar_ \\ 1_4 &\rightarrow 1_5 \end note that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand Unified Theory
A Grand Unified Theory (GUT) is a model in particle physics in which, at high energies, the three gauge interactions of the Standard Model comprising the electromagnetic, weak, and strong forces are merged into a single force. Although this unified force has not been directly observed, many GUT models theorize its existence. If unification of these three interactions is possible, it raises the possibility that there was a grand unification epoch in the very early universe in which these three fundamental interactions were not yet distinct. Experiments have confirmed that at high energy the electromagnetic interaction and weak interaction unify into a single electroweak interaction. GUT models predict that at even higher energy, the strong interaction and the electroweak interaction will unify into a single electronuclear interaction. This interaction is characterized by one larger gauge symmetry and thus several force carriers, but one unified coupling constant. Unifying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
Right Handed Neutrino
Sterile neutrinos (or inert neutrinos) are hypothetical particles (neutral leptons – neutrinos) that are believed to interact only via gravity and not via any of the other fundamental interactions of the Standard Model. The term ''sterile neutrino'' is used to distinguish them from the known, ordinary ''active neutrinos'' in the Standard Model, which carry an isospin charge of and engage in the weak interaction. The term typically refers to neutrinos with right-handed chirality (see right-handed neutrino), which may be inserted into the Standard Model. Particles that possess the quantum numbers of sterile neutrinos and masses great enough such that they do not interfere with the current theory of Big Bang Nucleosynthesis are often called neutral heavy leptons (NHLs) or heavy neutral leptons (HNLs). The existence of right-handed neutrinos is theoretically well-motivated, because the known active neutrinos are left-handed and all other known fermions have been observed ... [...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] |
E6 (mathematics)
In mathematics, E6 is the name of some closely related Lie groups, linear algebraic groups or their Lie algebras \mathfrak_6, all of which have dimension 78; the same notation E6 is used for the corresponding root lattice, which has rank 6. The designation E6 comes from the Cartan–Killing classification of the complex simple Lie algebras (see ). This classifies Lie algebras into four infinite series labeled A''n'', B''n'', C''n'', D''n'', and five exceptional cases labeled E6, E7, E8, F4, and G2. The E6 algebra is thus one of the five exceptional cases. The fundamental group of the complex form, compact real form, or any algebraic version of E6 is the cyclic group Z/3Z, and its outer automorphism group is the cyclic group Z/2Z. Its fundamental representation is 27-dimensional (complex), and a basis is given by the 27 lines on a cubic surface. The dual representation, which is inequivalent, is also 27-dimensional. In particle physics, E6 plays a role in some gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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