the lightest of the psi particles, the first particle to be discovered that contains a charmed quark.
Meet The Man Responsible For The Letter “J”
From its humble beginnings as a Roman numeral to its eventual tenth position in the English alphabet, J has had quite a linguistic journey. When was J added to the alphabet? J is a bit of a late bloomer; after all, it was the last letter added to the alphabet. It is no coincidence that I and J stand side by side—they actually started out as the same …
Word Fact: What’s the Name for the Dot Over the i and j?
While many languages, such as Arabic and Hebrew, add specific accents to the letters or characters throughout their alphabet, the English alphabet has only two letters that include a diacritic dot. This mark is added to a letter to signal a change in either the sound or meaning of a character. What is the additional name of this curious dot that hovers over the ninth …
Origin of J/psi particle
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
An electrically neutral meson having a mass 6,060 times that of the electron and a mean lifetime of approximately 1 X 10-20 seconds. The observation of this unusually long lifetime, in 1974, is what led to the hypothesis that other quarks existed in addition to the up, down, and strange quarks. It was the first firm experimental evidence for the charm quark and is considered to be a charm-anticharm quark pair. Also called J particle psi particle See Table at subatomic particle.
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