Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir . A very hard, brittle, silvery-white transition metal of the platinum family , iridium is the second- densest element (after osmium ) and is the most corrosion -resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.
Technicolor theories are models of physics beyond the standard model that address electroweak symmetry breaking , the mechanism through which elementary particles acquire masses. Early technicolor theories were modelled on quantum chromodynamics (QCD), the "color" theory of the strong nuclear force , which inspired their name.
In particle physics , color charge is a property of quarks and gluons that is related to the particles' strong interactions in the theory of quantum chromodynamics (QCD).
The Higgs boson or Higgs particle is an elementary particle initially theorised in 1964 , [ 6 ] [ 7 ] and tentatively confirmed to exist on 14 March 2013. [ 8 ] The discovery has been called "monumental" [ 9 ] [ 10 ] because it appears to confirm the existence of the Higgs field , [ 11 ] [ 12 ] which is pivotal to the Standard Model and other theories within particle physics , where it explains why some fundamental particles have mass when the symmetries controlling their interactions should require them to be massless, and—linked to this—why the weak force has a much shorter range than the electromagnetic force .
In particle and condensed matter physics , Goldstone bosons or Nambu–Goldstone bosons (NGBs) are bosons that appear necessarily in models exhibiting spontaneous breakdown of continuous symmetries . They were discovered by Yoichiro Nambu in the context of the BCS superconductivity mechanism, [ 1 ] and subsequently elucidated by Jeffrey Goldstone , [ 2 ] and systematically generalized in the context of quantum field theory . [ 3 ] These spinless bosons correspond to the spontaneously broken internal symmetry generators, and are characterized by the quantum numbers of these.
In particle physics , the strong interaction (also called the strong force , strong nuclear force , or color force ) is one of the four fundamental interactions of nature, the others being electromagnetism , the weak interaction and gravitation . At atomic scale, it is about 100 times stronger than electromagnetism, which in turn is orders of magnitude stronger than the weak force interaction and gravitation.
Gluons ( pron.: / ˈ ɡ l uː ɒ n z / ) are elementary particles that act as the exchange particles (or gauge bosons ) for the strong force between quarks , analogous to the exchange of photons in the electromagnetic force between two charged particles . [ 6 ] In technical terms, they are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry color charge , unlike the colorless photon , and therefore participate in the strong interaction in addition to mediating it, making QCD significantly harder to analyze than QED ( quantum electrodynamics ).
Pierre de Fermat ( French: [pjɛːʁ dəfɛʁma] ; 17 [ 1 ] August 1601 or 1607/8 [ 2 ] – 12 January 1665) was a French lawyer at the Parlement of Toulouse , France , and an amateur mathematician who is given credit for early developments that led to infinitesimal calculus , including his technique of adequality .
The fundamental theorem of calculus is a theorem that links the concept of the derivative of a function with the concept of the integral . The first part of the theorem, sometimes called the first fundamental theorem of calculus , shows that an indefinite integration [ 1 ] can be reversed by a differentiation.
A lepton is an elementary particle which does not undergo strong interactions, but is subject to the Pauli exclusion principle . [ 1 ] The best known of all leptons is the electron which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties . Two main classes of leptons exist: charged leptons (also known as the electron -like leptons), and neutral leptons (better known as neutrinos ). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium , while neutrinos rarely interact with anything, and are consequently rarely observed.
A quark ( pron.: / ˈ k w ɔr k / or / ˈ k w ɑr k / ) is an elementary particle and a fundamental constituent of matter . Quarks combine to form composite particles called hadrons , the most stable of which are protons and neutrons , the components of atomic nuclei . [ 1 ] Due to a phenomenon known as color confinement , quarks are never directly observed or found in isolation; they can be found only within hadrons, such as baryons (of which protons and neutrons are examples), and mesons . [ 2 ] [ 3 ] For this reason, much of what is known about quarks has been drawn from observations of the hadrons themselves.
In particle physics , mesons ( pron.: / ˈ m iː z ɒ n z / or / ˈ m ɛ z ɒ n z / ) are hadronic subatomic particles composed of one quark and one antiquark , bound together by the strong interaction . Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometre, which is about 2 ⁄ 3 the size of a proton or neutron .