Crossword clues for the word: POSITRON The word POSITRON has appeared as an answer to at least 9 crossword clues on different crossword puzzles. Crossword clues for POSITRON Showing 1 to 9 of 9 results Clue(s) "Beta decay emission, sometimes" Antielectron Antimatter particle Antiparticle first observed in 1929 Certain antiparticle First antiparticle discovered Is proton decaying into antimatter? Physics particle Subatomic particle