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Omega Meson
The omega meson () is a flavourless meson formed from a superposition of an up quark–antiquark and a down quark–antiquark pair. It is part of the vector meson nonet and mediates the nuclear force along with pions and rho mesons. Properties The most common decay mode for the ω meson is at 89.2±0.7%, followed by at 8.34±0.26%. The quark composition of the meson can be thought of as a mix between , and states, but it is very nearly a pure symmetric - state. This can be shown by deconstructing the wave function of the into its component parts. We see that the and mesons are mixtures of the SU(3) wave functions as follows. : \omega = \psi_8 \sin\theta + \psi_1 \cos\theta, : \phi = \psi_8 \cos\theta - \psi_1 \sin\theta, where : \theta is the nonet mixing angle, : \psi_1 = \frac and : \psi_8 = \frac. The mixing angle at which the components decouple completely can be calculated to be \arctan\frac\approx35.3^\circ, which almost corresponds to the actual value calcu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bosonic
In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0, 1, 2, ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have half odd-integer spin (1/2, 3/2, 5/2, ...). Every observed subatomic particle is either a boson or a fermion. Paul Dirac coined the name ''boson'' to commemorate the contribution of Satyendra Nath Bose, an Indian physicist. Some bosons are elementary particles occupying a special role in particle physics, distinct from the role of fermions (which are sometimes described as the constituents of "ordinary matter"). Certain elementary bosons (e.g. gluons) act as force carriers, which give rise to forces between other particles, while one (the Higgs boson) contributes to the phenomenon of mass. Other bosons, such as mesons, are composite particles made up of smaller constituents. Outside the realm of particle physics, multiple identical composite bosons behav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Physics (journal)
''Nuclear Physics A'', ''Nuclear Physics B'', ''Nuclear Physics B: Proceedings Supplements'' and discontinued ''Nuclear Physics'' are peer-reviewed scientific journals published by Elsevier. The scope of ''Nuclear Physics A'' is nuclear and hadronic physics, and that of ''Nuclear Physics B'' is high energy physics, quantum field theory, statistical systems, and mathematical physics. ''Nuclear Physics'' was established in 1956, and then split into ''Nuclear Physics A'' and ''Nuclear Physics B'' in 1967. A supplement series to ''Nuclear Physics B'', called ''Nuclear Physics B: Proceedings Supplements'' has been published from 1987 onwards until 2015 and continues as ''Nuclear and Particle Physics Proceedings''. ''Nuclear Physics B'' is part of the SCOAP3 initiative. Abstracting and indexing ''Nuclear Physics A'' * Current Contents ''Current Contents'' is a rapid alerting service database from Clarivate, formerly the Institute for Scientific Information and Thomson Reuters. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charm (quantum Number)
Charm (symbol ''C'') is a flavour quantum number representing the difference between the number of charm quarks () and charm antiquarks () that are present in a particle: :C = n_\text - n_\ By convention, the sign of flavour quantum numbers agree with the sign of the electric charge carried by the quarks of corresponding flavour. The charm quark, which carries an electric charge (''Q'') of +, therefore carries a charm of +1. The charm antiquarks have the opposite charge (), and flavour quantum numbers (). As with any flavour-related quantum numbers, charm is preserved under strong and electromagnetic interaction, but not under weak interaction (see CKM matrix). For first-order weak decays, that is processes involving only one quark decay, charm can only vary by 1 (). Since first-order processes are more common than second-order processes (involving two quark decays), this can be used as an approximate "selection rule" for weak decays.Alexander BelyaeChapter 17 Weak Interactio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strangeness
In particle physics, strangeness (symbol ''S'') is a property of particles, expressed as a quantum number, for describing decay of particles in strong and electromagnetic interactions that occur in a short period of time. The strangeness of a particle is defined as: S = -(n_\text - n_) where ''n'' represents the number of strange quarks () and ''n'' represents the number of strange antiquarks (). Evaluation of strangeness production has become an important tool in search, discovery, observation and interpretation of quark–gluon plasma (QGP). Strangeness is an excited state of matter and its decay is governed by CKM mixing. The terms ''strange'' and ''strangeness'' predate the discovery of the quark, and were adopted after its discovery in order to preserve the continuity of the phrase: strangeness of particles as −1 and anti-particles as +1, per the original definition. For all the quark flavour quantum numbers (strangeness, charm, topness and bottomness) the convent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-parity
In physics, the C parity or charge parity is a multiplicative quantum number of some particles that describes their behavior under the symmetry operation of charge conjugation. Charge conjugation changes the sign of all quantum charges (that is, additive quantum numbers), including the electrical charge, baryon number and lepton number, and the flavor charges strangeness, charm, bottomness, topness and Isospin (''I''3). In contrast, it doesn't affect the mass, linear momentum or spin of a particle. Formalism Consider an operation \mathcal that transforms a particle into its antiparticle, :\mathcal C \, , \psi\rangle = , \bar \rangle. Both states must be normalizable, so that : 1 = \langle \psi , \psi \rangle = \langle \bar , \bar \rangle = \langle \psi , \mathcal^\dagger \mathcal C, \psi \rangle, which implies that \mathcal C is unitary, :\mathcal C \mathcal^\dagger =\mathbf. By acting on the particle twice with the \mathcal operator, : \mathcal^2 , \psi\rangle = \ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parity (physics)
In physics, a parity transformation (also called parity inversion) is the flip in the sign of ''one'' spatial coordinate. In three dimensions, it can also refer to the simultaneous flip in the sign of all three spatial coordinates (a point reflection): \mathbf: \beginx\\y\\z\end \mapsto \begin-x\\-y\\-z\end. It can also be thought of as a test for chirality of a physical phenomenon, in that a parity inversion transforms a phenomenon into its mirror image. All fundamental interactions of elementary particles, with the exception of the weak interaction, are symmetric under parity transformation. As established by the Wu experiment conducted at the US National Bureau of Standards by Chinese-American scientist Chien-Shiung Wu, the weak interaction is chiral and thus provides a means for probing chirality in physics. In her experiment, Wu took advantage of the controlling role of weak interactions in radioactive decay of atomic isotopes to establish the chirality of the weak f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Angular Momentum
In quantum mechanics, the total angular momentum quantum number parametrises the total angular momentum of a given particle, by combining its orbital angular momentum and its intrinsic angular momentum (i.e., its spin). If s is the particle's spin angular momentum and ℓ its orbital angular momentum vector, the total angular momentum j is \mathbf j = \mathbf s + \boldsymbol ~. The associated quantum number is the main total angular momentum quantum number ''j''. It can take the following range of values, jumping only in integer steps: \vert \ell - s\vert \le j \le \ell + s where ''ℓ'' is the azimuthal quantum number (parameterizing the orbital angular momentum) and ''s'' is the spin quantum number (parameterizing the spin). The relation between the total angular momentum vector j and the total angular momentum quantum number ''j'' is given by the usual relation (see angular momentum quantum number) \Vert \mathbf j \Vert = \sqrt \, \hbar The vector's ''z''-projection i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Parity
In particle physics, G-parity is a multiplicative quantum number that results from the generalization of C-parity to multiplets of particles. ''C''-parity applies only to neutral systems; in the pion triplet, only π0 has ''C''-parity. On the other hand, strong interaction does not see electrical charge, so it cannot distinguish amongst π+, π0 and π−. We can generalize the ''C''-parity so it applies to all charge states of a given multiplet: :\mathcal G \begin \pi^+ \\ \pi^0 \\ \pi^- \end = \eta_G \begin \pi^+ \\ \pi^0 \\ \pi^- \end where ''ηG'' = ±1 are the eigenvalues of ''G''-parity. The ''G''-parity operator is defined as :\mathcal G = \mathcal C \, e^ where \mathcal C is the ''C''-parity operator, and ''I''2 is the operator associated with the 2nd component of the isospin "vector". ''G''-parity is a combination of charge conjugation and a π rad (180°) rotation around the 2nd axis of isospin space. Given that charge conjugation and isospin are preserved b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isospin
In nuclear physics and particle physics, isospin (''I'') is a quantum number related to the up- and down quark content of the particle. Isospin is also known as isobaric spin or isotopic spin. Isospin symmetry is a subset of the flavour symmetry seen more broadly in the interactions of baryons and mesons. The name of the concept contains the term ''spin'' because its quantum mechanical description is mathematically similar to that of angular momentum (in particular, in the way it couples; for example, a proton–neutron pair can be coupled either in a state of total isospin 1 or in one of 0). But unlike angular momentum, it is a dimensionless quantity and is not actually any type of spin. Before the concept of quarks was introduced, particles that are affected equally by the strong force but had different charges (e.g. protons and neutrons) were considered different states of the same particle, but having isospin values related to the number of charge states. A close exami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of second. The speed of light is invariant (physics), the same for all observers, no matter their relative velocity. It is the upper limit for the speed at which Information#Physics_and_determinacy, information, matter, or energy can travel through Space#Relativity, space. All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and sensitive measurements, their finite speed has noticeable effects. Much starlight viewed on Earth is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When Data communication, comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Volt
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an electric potential difference of one volt in vacuum. When used as a unit of energy, the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI, this sets 1 eV equal to the exact value Historically, the electronvolt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences, because a particle with electric charge ''q'' gains an energy after passing through a voltage of ''V''. Definition and use An electronvolt is the amount of energy gained or lost by a single electron when it moves through an electric potential difference of one volt. Hence, it has a value of one volt, which is , multiplied by the elementary charge Therefore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rest Mass
The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, it is a characteristic of the system's total energy and momentum that is the same in all frames of reference related by Lorentz transformations.Lawrence S. LernerPhysics for Scientists and Engineers, Volume 2, page 1073 1997. If a center-of-momentum frame exists for the system, then the invariant mass of a system is equal to its total mass in that "rest frame". In other reference frames, where the system's momentum is non-zero, the total mass (a.k.a. relativistic mass) of the system is greater than the invariant mass, but the invariant mass remains unchanged. Because of mass–energy equivalence, the rest energy of the system is simply the invariant mass times the speed of light squared. Similarly, the total energy of the system is its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
