subatomic
71gamma ray — Physics. 1. a photon of penetrating electromagnetic radiation (gamma radiation) emitted from an atomic nucleus. 2. a photon emitted by an electron as a result of internal conversion. 3. electromagnetic radiation with wavelengths shorter than… …
72neutrino — /nooh tree noh, nyooh /, n., pl. neutrinos. Physics. any of the massless or nearly massless electrically neutral leptons. There is a distinct kind of neutrino associated with each of the massive leptons. Cf. antineutrino, lepton, conservation of… …
73quantum chromodynamics — Physics. a quantum field theory that describes quarks and gluons and their interactions, with the color of the quarks playing a role analogous to that of electric charge. Abbr.: QCD Also called chromodynamics. Cf. color (def. 18). [1975 80] * * * …
74quantum mechanics — quantum mechanical, adj. Physics. a theory of the mechanics of atoms, molecules, and other physical systems that are subject to the uncertainty principle. Abbr.: QM Cf. nonrelativistic quantum mechanics, relativistic quantum mechanics. [1920 25]… …
75spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
76weak force — Physics. a force between elementary particles that causes certain processes that take place with low probability, as radioactive beta decay and collisions between neutrinos and other particles. Also called weak interaction force. Cf. weak… …
77Einstein's mass-energy relation — Relationship between mass (m) and energy (E) in Albert Einstein s special theory of relativity, expressed E = mc2, where c equals 186,000 mi/second (300,000 km/second), the speed of light. Whereas mass and energy were viewed as distinct in… …
78Gell-Mann, Murray — born Sept. 15, 1929, New York, N.Y., U.S. U.S. physicist. He entered Yale University at 15 and earned his Ph.D. from the Massachusetts Institute of Technology in 1951. From 1955 he taught at the California Institute of Technology, becoming… …
79radiation measurement — ▪ technology Introduction technique for detecting the intensity and characteristics of ionizing radiation, such as alpha, beta, and gamma rays or neutrons, for the purpose of measurement. The term ionizing radiation refers to those… …
80Natural scientific research in Canada — This article outlines the history of natural scientific research in Canada, including mathematics, physics, astronomy, space science, geology, oceanography, chemistry, biology, medical research and psychology. The social sciences are not treated… …
