The Universe is so huge and expanding. It is infinite. The Macro-universe is so wonderful thing to explore with infinite number of celestial physical bodies of matter like comets, planets, stars, constellations, galaxies, expanding space with cosmic radiation and colourful lights: the Micro-universe of particles and elementary particles that are believed to be the building blocks of the Universe are equally absorbing infinity of exploration. All colours, lights, energy, forces, consolidation / disintegration of matter and movements seem to be the play of particles.
All matter, the substance of all physical objects from atoms and other particles to stars have mass and occupy a volume of space (we ignore the fact that alternative scientific meanings of "matter" in different subjects of study may be even incompatible). But the smallest bits of matter are called particles. The ultimate goal of scientific investigators would be breakdown into the internal substructure of all particles to find out the unique fundamental source of all matter in the Universe.
As the scientists delved deeper and deeper into particles, they identified Elementary or Fundamental particles that are believed not to have substructure. The process seems to be never ending: instead of one or a few elementary particles, they have come to identify, speculate and detect many such elementary particles! the small particle, Atom,which was thought to be an elementary particle initially soon turned out to have a substructure with even smaller particles like electrons, protons and neutron forming the nuclei of atoms. Even protons and neutrons are not elementary particles. In the
In theStandard Model of particle physics, the quarks, leptons, and gauge bosons are elementary particles.
Quarks, an elementary particle and a fundamental constituent of matter, combine to form composite particles called hadrons, the most stable of which are protons and neutrons.
Gluons are elementary particles which act as the exchange particles (gauge bosons) for the color force between quarks, analogous to the exchange of photons in the electromagnetic force between two charged particles. quarks make up the baryons (composite of three quarks) and the strong interaction takes place between baryons, one could say that the color force is the source of the strong interaction, or that the strong interaction is like a residual color force which extends beyond the baryons, for example when protons and neutrons are bound together in a nucleus.
Bosonic particles that act as carriers of the fundamental forces of nature: particles exert forces on each other by the exchange of gauge bosons.
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 positron's, while neutrinos rarely interact with anything, and are consequently rarely observed: neutrino usually travels close to the speed of light, is electrically neutral, and is able to pass through ordinary matter almost undisturbed. This makes neutrinos extremely difficult to detect. Neutrinos have a very small, but non-zero rest mass.
Bosonic particles that act as carriers of the fundamental forces of nature: particles exert forces on each other by the exchange of gauge bosons.
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 positron's, while neutrinos rarely interact with anything, and are consequently rarely observed: neutrino usually travels close to the speed of light, is electrically neutral, and is able to pass through ordinary matter almost undisturbed. This makes neutrinos extremely difficult to detect. Neutrinos have a very small, but non-zero rest mass.
A fermion can be an elementary particle, like the electron, or a composite particle, like the proton.There are 12 flavors of elementary fermions, plus their corresponding antiparticles, as well as elementary bosons that mediate the forces and the still undiscovered Higgs boson. There may also be elementary particles not described by the Standard Model, such as the graviton, the particle that would carry the gravitational force or the sparticles, supersymmetric partners of the ordinary particles.
The 12 fundamental fermionic flavours are divided into three generations of four particles each. Six of the particles are quarks. The remaining six are leptons, three of which are neutrinos, and the remaining three of which have an electric charge of −1: the electron and its two cousins, the muon and the tau. So, we have electron, electron nutrino, muon, muon nutrino, tau, tau nutrino, up quark, down quark, charm quark, strange quark, top quark and bottom quark. 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. There are also 12 fundamental fermionic antiparticles: anti-electron (positron), electron anti-nutrino, antimuon, muon anti-nutrino, tau, tau anti-nutrino, up antiquark, down antiquark, charm antiquark, strange antiquark, top antiquark and bottom antiquark.
Isolated quarks and antiquarks have never been detected, a fact explained by confinement. Every quark carries one of three color charges of the strong interaction; antiquarks similarly carry anticolor. Color charged particles interact via gluon exchange in the same way that charged particles interact via photon exchange. However, gluons are themselves color charged, resulting in an amplification of the strong force as color charged particles are separated. Unlike the electromagnetic force which diminishes as charged particles separate, color charged particles feel increasing force. Color charged particles may combine to form color neutral composite particles called hadrons. A quark may pair up with an antiquark: the quark has a color and the antiquark has the corresponding anticolor. The color and anticolor cancel out, forming a color neutral meson. Alternatively, three quarks can exist together, one quark being "red", another "blue", another "green". These three colored quarks together form a color-neutral baryon. Symmetrically, three antiquarks with the colors "antired", "antiblue" and "antigreen" can form a color-neutral antibaryon. Evidence for the existence of quarks comes from deep inelastic scattering: firing electrons at nuclei to determine the distribution of charge within nucleons (which are baryons). If the charge is uniform, the electric field around the proton should be uniform and the electron should scatter elastically. Low-energy electrons do scatter in this way, but above a particular energy, the protons deflect some electrons through large angles. The recoiling electron has much less energy and a jet of particles is emitted. This inelastic scattering suggests that the charge in the proton is not uniform but split among smaller charged particles: quarks.
Gluons are the mediators of the strong interaction and carry both colour and anticolour. Although gluons are massless, they are never observed in detectors due to colour confinement; rather, they produce jets of hadrons, similar to single quarks. The first evidence for gluons came from annihilations of electrons and antielectrons at high energies which sometimes produced three jets — a quark, an antiquark, and a gluon.
The fundamental forces of nature are mediated by gauge bosons, and mass is hypothesized to be created by the Higgs boson. There are three weak gauge bosons: W+, W−, and Z0; these mediate the weak interaction. The massless photon mediates the electromagnetic interaction. The Higgs boson itself has not yet been observed in detectors.
Existence of more elementary particles have been identified or speculated by the scientists: one class of these are supersymmetric particles or sparticles. Each particle in the Standard Model would have a superpartner whose spin differs by 1/2 from the ordinary particle. There are a whole list of names of elementary particles / particles here: neutrilinos (superpartners of neutral Higgs bosons, Z bosons and photon), chargino (superpartner of charged bosons), photino (sp of photon), wino ( sp of W bosons), zino (sp of Z boson), Higgisions (sp of Higgs bosons), gluino (sp of gluons), gravitino (sp of graviton), sleptons (sp of leptons), sneutrino (sp of neutrino) and squarks (sp of quarks).
There are stll more elementary particles: graviscalar, graviphoton,axion, saxion, axino, saxion, branon, dilaton, dilatino, leptoquarks X and Y bosons, magnetic photon, majoron and majorana.
We are virtually flooded with elementary particles of different kinds. The explain or predictably potential in explaining the material universe. But then the Universe is dependent on too many fundamental building blocks. We do not know how they came into existence except from the Big Bang general source of Energy Concentrate in the continuous process of losing density. In that case, they are not the building blocks of the Universe: they are the result of the dilution of energy.
The Truely Fundamental Particles could not have been too many and must be capable of explaining the high density energy concentrate itself and its inflationary behaviour. The Fundemental Elementary Particles or constiuent of the Universe are still illuding us. What we know so far and in the process of knowing is the properties and chracteristics of particles that help explain the operation of other particles and forces but not yet amenable to investigation as how they are sourced from the basic orgin of all matter. The String Theory talks of particles not being point particles but closed or open strings and may help better explain how the particles behave. But does string theory yet solve our problem of too many elementary particles? Maybe the concept of strings and branes have given us the desired direction of investigation. If the vibration of strings produce elementary particles, the strings themselves may be the path to the origin of all matter, energy, space and time!
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