Search results
Results from the WOW.Com Content Network
These particles are unphysical and unobservable. These include: Ghost particles, like Faddeev–Popov ghosts and Pauli–Villars ghosts; Spurions, auxiliary field in a quantum field theory that can be used to parameterize any symmetry; Soft photons, photons with energies below detectable in experiment.
Leptoquark, hypothetical particles that are neither bosons or fermions but carry lepton and baryon numbers. Magnetic monopole is a generic name for particles with non-zero magnetic charge. They are predicted by Grand Unification Theories. These may include: Dirac monopoles, monopole that would allow charge quantization.
Another type, microscopic particles usually refers to particles of sizes ranging from atoms to molecules, such as carbon dioxide, nanoparticles, and colloidal particles. These particles are studied in chemistry, as well as atomic and molecular physics. The smallest particles are the subatomic particles, which refer to particles smaller than ...
Known examples of such elementary particles include photons, Z bosons, and Higgs bosons, along with the hypothetical neutralinos, sterile neutrinos, and gravitons. For a spin-½ particle such as the neutralino, being truly neutral implies being a Majorana fermion. Composite particles can also be truly neutral.
According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a baryon, like a proton or a neutron, composed of three quarks; or a meson, composed of two quarks), or an elementary particle, which is not composed of other particles (for example ...
Particles of different sizes deposit in different regions of the respiratory tract, leading to various health effects. [153] The particles are grouped by sizes: [154] Coarse particles (PM 10), with diameters between 2.5 and 10 micrometers, are inhalable and can deposit in the upper airways, including the nose, throat, and bronchi. [154]
Virtual particles are often popularly described as coming in pairs, a particle and antiparticle which can be of any kind. These pairs exist for an extremely short time, and then mutually annihilate, or in some cases, the pair may be boosted apart using external energy so that they avoid annihilation and become actual particles, as described below.
[4] [5] Many theoretical elaborations upon, and beyond, the Standard Model have been made since its codification in the 1970s. These include notions of supersymmetry, which double the number of elementary particles by hypothesizing that each known particle associates with a "shadow" partner far more massive.