eta prime meson
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eta prime meson
n.
An electrically neutral meson having a mass 1,874 times that of the electron and a mean lifetime of about 3 × 10-21 second.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.