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hypothetical particle
subject			fact

hypothetical particle	has acceptance status hypothetical
	is a kind of particle
particle	obeys uncertainty principle
	has frequency inversely proportional to the wavelength
	has wavelength inversely proportional to its momentum
	has charge
	has mass
physical object	has location or center of gravity
	has angular momentum
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of hypothetical particle :

• axion (5 facts) - A hypothetical spin-0 particle with a very small mass of 10^-5-10^-3 eV. It was postulated in order to provide a natural solution to the "strong CP problem".
• dark matter (25 kinds, 116 facts) (hidden mass) - Material astronomers cannot see but whose presence they believe in either because they detect its gravitational influence or because certain theories predict its existence. For example, astronomers believe that the outer part of the Galaxy harbors dark matter, because they notice its gravitational influence on the stars they can see; and inflationary cosmologists believe that the universe is full of dark matter, because inflation predicts that the universe has a large density., Any form of matter which exists in the Universe in a non-luminous form., Matter whose existence is inferred on the basis of dynamical studies - e.g., the orbits of stars, in galaxies - but which does not show up as bright objects such as stars and nebulae. Its composition is unknown: It might consist of subatomic particles, or of dim dwarf stars or black holes, or a combination of various sorts of objects., Matter that is invisible to us because it emits little or no light. As much as 90%-99% of the mass of the universe may be dark., Matter that is detected only by its gravitational pull on visible matter. At least 90%, and possibly 99% of the matter in the universe is dark. The composition is unknown; it might consist of very low mass stars or supermassive black holes, but big-bang nucleosynthesis calculations limit the amount of such baryonic matter to a small fraction of the critical mass density. If the mass density is critical, as predicted by the simplest versions of inflation, then the bulk of the dark matter must be a gas of weakly interacting non-baryonic particles, sometimes called WIMPS (Weakly Interacting Massive Particles). Various extensions of the standard model of particle physics suggest specific candidates for the WIMPs., Matter in the universe that we detect by its gravitational influences, yet do not see. Dark matter that has small random speed and is easily concentrated by gravity is called cold dark matter. Dark matter that has large random speed and is thus able to resist gravitational clumping is called hot dark matter. Recent models to explain the observed pattern of galaxy clustering can be characterized, in part, as to whether they invoke hot dark matter or cold dark matter. However, since we do not know what the dark matter is, we do not have any direct evidence of whether it is cold or hot., Matter whose presence is inferred from dynamical measurements but which has no optical counterpart. The luminous regions of galaxies have mass-luminosity ratios of about 10. However, the mass-luminosity ratio in the outer halos of many spiral galaxies is 100 or more; one sees the brightness fall off with distance from the center of the galaxy but considerable mass is present. A similar situation prevails in galaxy clusters, where nonluminous matter must provide most of the self-gravitational attraction that holds the clusters together. The missing mass is not really missing; it is present but invisible (at least to current detectors). It is generally believed to consist either of the remnants of massive stars or of planetary-sized objects comparable in mass to Jupiter.
• glueball (2 facts) - Theoretical particles made exclusively of gluons. Tentative evidence of the existence of glueballs had been found in accelerator experiments by the mid-1980s.
• Goldstone boson (4 facts) - A massless spin-0 particle which arises whenever a (continuous) global symmetry is spontaneously broken.
• gravitino (2 facts) - Hypothetical force-carrying particles predicted by supersymmetry theories. The gravitino's spin would be 1/2. Its mass is unknown.
• graviton (12 facts) - A massless spin-2 particle which is the hypothetical quantum of the gravitational field. It mediates the force of gravity in a similar way to that in which the spin-1 gauge bosons (i.e. the photon, W^±, Z⁰, and gluons) mediate the other forces., A hypothetical elementary particle associated with the gravitational interaction. It is a stable particle with zero rest mass, zero charge, and a spin of ± 2, and travels with the speed of light., Smallest bundle of the gravitational force field; messenger particle for the gravitational force., The hypothetical quantum particle of the gravitational field. It could also be thought of as a quantized element of space-time curvature., A quantum of gravitational radiation., The quanta thought to convey gravitational force; analogous to the photons, gluons, and intermediate vector bosons of electromagnetism and the strong and weak nuclear forces. Predicted by quantum theory of gravity, gravitons have not yet been detected.
• Higgs boson (4 facts) - The particle or particles associated with the bundles of energy in the Higgs field. Such particles are analogous to the photons that are associated with the electromagnetic field. The standard model of particle physics predicts one electrically neutral Higgs particle which has not yet been found, but which will be sought in upcoming particle accelerator experiments. The grand unified theories predict many Higgs particles, but they are too massive to be accessible at existing or foreseeable accelerators., A hypothetical, spinless particle that plays an important role in the Glashow-Weinberg-Salam electroweak theory (and in other theories involving spontaneous symmetry breaking, e.g. GUTs).
• magnetic monopole (6 facts) - A hypothetical particle that carries an isolated north or south magnetic pole. This is in contrast to magnets which are north-south pole pairs. If magnetic monopoles exist, they must be very massive., a massive particle with but one magnetic pole, the production of which is indicated in some theories of the early universe., A magnet with an isolated north (or south) pole, rather than a pair of equal-strength north and south poles, as in conventional magnets. Magnetic monopoles have never been observed, but they are predicted to exist by grand unified theories., An hypothesized particle that would have either a magnetic north pole or a magnetic south pole but not both. all magnetic particles and magnets ever observed have both poles. Magnetic monopoles are predicted by grand unified theories of physics. that grand unified theories predict the existence of large numbers of magnetic monopoles, when none have been discovered, is called the monopole problem. (see grand unified theories.), has definition A hypothetical quantum object being a single, isolated magnetic pole. Normally, magnetic poles, the sources of a magnetic field, occur in pairs as north and south poles.
• parton (12 kinds, 56 facts) - A generic term used to describe any particle which may be present inside nucleons. It includes quarks, antiquarks and gluons., A hypothetical pointlike constituent of a nucleon, which contains all the charge of the nucleon.
• shadow matter (2 facts) - Theoretical classes of particles, their existence intimated by supersymmetry, theory, that participate in few if any of the four known fundamental forces. Planets, stars, and galaxies made of shadow matter could conceivably exist in the same space and time we occupy without our sensing their presence.
• sparticle (2 facts) - Hypothetical particle which is predicted by some Grand Unified Theories.
• superpartner (2 facts) - Particle whose spins differ by 1/2 unit and that are paired by supersymmetry.
• tachyon (2 facts) - Particle whose mass (squared) is negative; its presence in a theory generally yields inconsistencies.
• vector boson (2 kinds, 15 facts) (IVB) - Force-carrying particles of nature. Three vector bosons are responsible for the weak nuclear force. By admitting the photon on an equal footing it is possible to create a unified electroweak theory. As a result of symmetry-breaking processes, however, this photon remains massless while the three other vector bosons pick up mass., Also called the intermediate vector boson., A hypothetical elementary particle that acts as intermediary for the weak interaction, carrying its effect from one particle to another as the photon does for electromagnetic interactions and as various mesons do for the strong interactions.