Strangeness

Flavour in particle physics v • d • e
Flavour quantum numbers: Lepton number: L Baryon number: B Strangeness: S Charm: C Bottomness: B' Topness: T Isospin: I_z or I Weak isospin: T_z Electric charge: Q Combinations: Hypercharge: Y Y=2(Q-I_z) Weak hypercharge: Y_W Y_W=2(Q-T_z) Y_W=B−L Related topics: CPT symmetry CKM matrix CP symmetry Chirality

In particle physics, strangeness, denoted as $S$ , is a property of particles, expressed as a quantum number for describing decay of particles in strong and electro-magnetic reactions, which occur in a short period of time. In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their Particle physics is a branch of Physics that studies the elementary constituents of Matter and Radiation, and the interactions between them Quantum numbers describe values of conserved numbers in the dynamics of the Quantum system. In High energy physics, the lepton number is the number of Leptons minus the number of antileptons In Particle physics, the baryon number is an approximate conserved Quantum number of a system The charm Quark is a second-generation quark with an electric charge of +(2/3 e. The bottom quark is a third-generation Quark with a charge of − e. The top quark is the third- generation up-type Quark with a charge of +(2/3 e. In Physics, and specifically Particle physics, isospin ( isotopic spin, isobaric spin) is a Quantum number related to the The weak isospin in Particle physics is a quantum number relating to the Weak interaction, and parallels the idea of Isospin under the Strong Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. In Particle physics, the hypercharge (represented by Y) of a particle is related to the Strong interaction, and it should not be confused with similarly The weak hypercharge in Particle physics is a quantum number relating the Electrical charge and the third component of Weak isospin, and is similar In High energy physics, B−L (pronounced "bee minus ell" is the Baryon number minus the Lepton number. CPT symmetry is a fundamental symmetry of Physical laws under transformations that involve the inversions of charge, parity and In the Standard Model of Particle physics, the Cabibbo-Kobayashi-Maskawa matrix ( CKM matrix, quark mixing matrix, sometimes also called In Particle physics, CP violation is a violation of the postulated CP symmetry of the laws of physics A phenomenon is said to be chiral if it is not identical to its Mirror image (see Chirality) Particle physics is a branch of Physics that studies the elementary constituents of Matter and Radiation, and the interactions between them Quantum numbers describe values of conserved numbers in the dynamics of the Quantum system. In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and In Physics, the electromagnetic force is the force that the Electromagnetic field exerts on electrically charged particles The strangeness of a particle is defined as:

$S = N_s - N_{\overline{s}}$

where $N_{\overline{s}}$ represents the number of strange anti-quarks ( ${\overline{s}}$ ) and $N_s \$ represents the number of strange quarks.

The derivation of the phrase "strange" or "strangeness" precedes the discovery of the quark, and was adopted after its discovery in order to preserve the continuity of the phrase; strangeness of anti-particles being referred to as +1, and particles as −1 as per the original definition. For all the quark flavor quantum numbers (strangeness, charm, topness and bottomness) the convention is that the flavor charge and the electric charge of a quark have the same sign. In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their With this, any flavor carried by a charged meson has the same sign as its charge. In Particle physics, a meson is a strongly interacting Boson &mdashthat is a Hadron with integer spin.

Strangeness conservation

Strangeness was introduced by Murray Gell-Mann and Kazuhiko Nishijima to explain the fact that certain particles, such as the kaons or certain hyperons, were created easily in particle collisions, yet decayed much more slowly than expected for their large masses and large production cross sections. Murray Gell-Mann (born September 15, 1929) is an American Physicist who received the 1969 Nobel Prize in physics for his work In Particle physics, a kaon (/ˈkeɪɒn/ also called K-meson and denoted) is any one of a group of four Mesons distinguished by the fact that they In Particle physics, a hyperon is any Baryon containing a Strange quark, but no Charm quarks or Bottom quarks Properties In nuclear and Particle physics, the concept of a cross section is used to express the likelihood of interaction between particles Noting that collisions seemed to always produce pairs of these particles, it was postulated that a new conserved quantity, dubbed "strangeness", was preserved during their creation, but not conserved in their decay.

In our modern understanding, strangeness is conserved during the strong and the electromagnetic interactions, but not during the weak interactions. In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and In Physics, the electromagnetic force is the force that the Electromagnetic field exerts on electrically charged particles The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature Consequently, the lightest particles containing a strange quark cannot decay by the strong interaction, and must instead decay via the much slower weak interaction. In most cases these decays change the value of the strangeness by one unit. However, this doesn't necessarily hold in second-order weak reactions, where there are mixes of K⁰ and K⁰ mesons.

References

Griffiths, David J. (1987). Introduction to Elementary Particles. Wiley, John & Sons, Inc. ISBN 0-471-60386-4.

Dictionary

-noun

Condition of being strange, odd, or weird.
(physics) one of the quantum numbers of subatomic particles that depends upon the relative number of strange quarks and anti-strange quarks

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Strangeness conservation

References

See also

Dictionary

strangeness

-noun