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Exotic Hadron
Exotic hadrons are subatomic particles composed of quarks and gluons, but which – unlike "well-known" hadrons such as protons, neutrons and mesons – consist of more than three valence quarks. By contrast, "ordinary" hadrons contain just two or three quarks. Hadrons with explicit valence gluon content would also be considered exotic. In theory, there is no limit on the number of quarks in a hadron, as long as the hadron's color charge is white, or color-neutral. Consistent with ordinary hadrons, exotic hadrons are classified as being either fermions, like ordinary baryons, or bosons, like ordinary mesons. According to this classification scheme, pentaquarks, containing five valence quarks, are exotic baryons, while tetraquarks (four valence quarks) and hexaquarks (six quarks, consisting of either a dibaryon or three quark-antiquark pairs) would be considered exotic mesons. Tetraquark and pentaquark particles are believed to have been observed and are being investigated; hexa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-matrix
In physics, the ''S''-matrix or scattering matrix is a Matrix (mathematics), matrix that relates the initial state and the final state of a physical system undergoing a scattering, scattering process. It is used in quantum mechanics, scattering theory and quantum field theory (QFT). More formally, in the context of QFT, the ''S''-matrix is defined as the unitary matrix connecting sets of asymptotically free particle states (the ''in-states'' and the ''out-states'') in the Hilbert space of physical states: a multi-particle state is said to be ''free'' (or non-interacting) if it Representation theory of the Lorentz group, transforms under Lorentz transformations as a tensor product, or ''direct product'' in physics parlance, of ''one-particle states'' as prescribed by equation below. ''Asymptotically free'' then means that the state has this appearance in either the distant past or the distant future. While the ''S''-matrix may be defined for any background (spacetime) that is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belle Experiment
The Belle experiment was a particle physics experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers, at the High Energy Accelerator Research Organisation ( KEK) in Tsukuba, Ibaraki Prefecture, Japan. The experiment ran from 1999 to 2010. The Belle detector was located at the collision point of the asymmetric-energy electron–positron collider, KEKB. Belle at KEKB together with the BaBar experiment at the PEP-II accelerator at SLAC were known as the B-factories as they collided electrons with positrons at the center-of-momentum energy equal to the mass of the (4S) resonance which decays to pairs of B mesons. The Belle detector was a hermetic multilayer particle detector with large solid angle coverage, vertex location with precision on the order of tens of micrometres (provided by a silicon vertex detector), good distinction between pions and kaons in the momenta range from 100 MeV/c to few GeV/c (provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LHCb
The LHCb (Large Hadron Collider beauty) experiment is a particle physics detector collecting data at the Large Hadron Collider at CERN. LHCb specializes in the measurements of the parameters of CP violation in the interactions of b- and c-hadrons (heavy particles containing a bottom and charm quarks). Such studies can help to explain the matter-antimatter asymmetry of the Universe. The detector is also able to perform measurements of production cross sections, exotic hadron spectroscopy, and electroweak physics in the forward region. The LHCb collaborators, who built, operate and analyse data from the experiment, are composed of approximately 1650 people from 98 scientific institutes, representing 22 countries. Vincenzo Vagnoni succeeded on July 1, 2023 as spokesperson for the collaboration from Chris Parkes (spokesperson 2020–2023). The experiment is located at point 8 on the LHC tunnel close to Ferney-Voltaire, France just over the border from Geneva. The (small) MoEDA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid Hadrons
Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two different genetic parent strains * Hybrid (particle physics), a valence quark-antiquark pair and one or more gluons * Hybrid solar eclipse, a rare solar eclipse type * Hybrid star (other), with properties normally found in different types of stars Technology Transportation * Hybrid vehicle (other), various types of vehicles referred to as hybrids * Hybrid rail, an urban rail service for passengers using lightweight trains * Hybrid rocket, a rocket motor using propellants from two different states of matter * Hybrid shipping container, a container using phase change material in combination with the ability to recharge itself * Hybrid train, a locomotive, railcar, or train that uses an onboard rechargeable energy storage s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glueball
In particle physics, a glueball (also gluonium, gluon-ball) is a hypothetical composite particle. It consists solely of gluon particles, without valence quarks. Such a state is possible because gluons carry color charge and experience the strong interaction between themselves. Glueballs are extremely difficult to identify in particle accelerators, because they mix with ordinary meson states. In pure gauge theory, glueballs are the only states of the spectrum and some of them are stable. Theoretical calculations show that glueballs should exist at energy ranges accessible with current technology. However, due to the aforementioned difficulty (among others), they have so far not been observed and identified with certainty, although phenomenological calculations have suggested ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics Letters
''Physics Letters'' was a scientific journal published from 1962 to 1966, when it split in two series now published by Elsevier Elsevier ( ) is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell (journal), Cell'', the ScienceDirect collection of electronic journals, ...: *''Physics Letters A'': condensed matter physics, theoretical physics, nonlinear science, statistical physics, mathematical and computational physics, general and cross-disciplinary physics (including foundations), atomic, molecular and cluster physics, plasma and fluid physics, optical physics, biological physics and nanoscience. *''Physics Letters B'': nuclear physics, theoretical nuclear physics, experimental high-energy physics, theoretical high-energy physics, and astrophysics. ''Physics Letters B'' is part of the SCOAP3 initiative. References See also * List of periodicals published by Elsevier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Chromodynamics
In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group special unitary group, SU(3). The QCD analog of electric charge is a property called ''color''. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of Quantum chromodynamics#Experimental tests, experimental evidence for QCD has been gathered over the years. QCD exhibits three salient properties: * Color confinement. Due to the force between two color charges remaining constant as they are separated, the energy grows until a quark–antiquark pair is mass–energy equivalence, spontaneously produced, turning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Murray Gell-Mann
Murray Gell-Mann (; September 15, 1929 – May 24, 2019) was an American theoretical physicist who played a preeminent role in the development of the theory of elementary particles. Gell-Mann introduced the concept of quarks as the fundamental building blocks of the strongly interacting particles, and the renormalization group as a foundational element of quantum field theory and statistical mechanics. He played key roles in developing the concept of chirality in the theory of the weak interactions and spontaneous chiral symmetry breaking in the strong interactions, which controls the physics of the light mesons. In the 1970s he was a co-inventor of quantum chromodynamics (QCD) which explains the confinement of quarks in mesons and baryons and forms a large part of the Standard Model of elementary particles and forces. Murray Gell-Mann received the 1969 Nobel Prize in Physics for his work on the theory of elementary particles. Life and education Gell-Mann was bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-matrix
In mathematics, a -matrix is a complex square matrix with every principal minor is positive. A closely related class is that of P_0-matrices, which are the closure of the class of -matrices, with every principal minor \geq 0. Spectra of -matrices By a theorem of Kellogg, the eigenvalues of - and P_0- matrices are bounded away from a wedge about the negative real axis as follows: :If \ are the eigenvalues of an -dimensional -matrix, where n>1, then ::, \arg(u_i), < \pi - \frac,\ i = 1,...,n :If , , are the eigenvalues of an -dimensional -matrix, then :: Remarks The class of nonsingular ''M''-matrices is a subset of the class of -matrices. More precisely, all matrices that are both -matrices and[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
