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pion
(Encyclopedia)pion pīˈŏn [key] or pi meson, lightest of the meson family of elementary particles. The existence of the pion was predicted in 1935 by Hideki Yukawa, who theorized that it was responsible for the f...muon
(Encyclopedia)muon myo͞oˈŏn [key], elementary particle heavier than an electron but lighter than other particles having nonzero rest mass. The name muon is derived from mu meson, the former name of the particle....meson
(Encyclopedia)meson mēˈzŏn [key] [Gr.,=middle (i.e., middleweight)], class of elementary particles whose masses are generally between those of the lepton class of lighter particles and those of the baryon class ...nucleus, in physics
(Encyclopedia)nucleus, in physics, the extremely dense central core of an atom. Following the discovery of radioactivity by A. H. Becquerel in 1896, Ernest Rutherford identified two types of radiation given off b...Japan
(Encyclopedia) CE5 Japan jəpănˈ [key], Jap. Nihon or Nippon, country (2015 est. pop. 127,975,000), 145,833 sq mi (377,835 sq km), occupying an archipelago off the coast of E Asia. The capital is Tokyo, which, ...elementary particles
(Encyclopedia) CE5 elementary particles, the most basic physical constituents of the universe. The first subatomic particle to be discovered was the electron, identified in 1897 by J. J. Thomson. After the...Nobel Prizes (table)
(Encyclopedia)Nobel Prizesphysics
(Encyclopedia)physics, branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this na...Browse by Subject
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