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Definition of Z PARTICLE
: a neutral elementary particle about 90 times heavier than a proton that along with the W particle is a transmitter of the weak force —called also Z0, or Z0 particle
First Known Use of Z PARTICLE
Electrically neutral carrier of the weak force and the neutral partner of the electrically charged W particle. It is nearly 100 times more massive than the proton and has a lifetime of only about 1025 second. Z particles were first observed in 1983 by Carlo Rubbia and Simon van der Meer at CERN. Further studies have shown a natural variation in mass that is related to the particle's lifetime through the uncertainty principle. Measurements show that when Z particles decay to neutrino-antineutrino pairs (seepair production), they produce only three types of lightweight neutrino, indicating that there are only three sets each of leptons and quarks.