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Upsilon Particle
The Upsilon meson () is a quarkonium state (i.e. Flavour (particle physics), flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, headed by Leon Lederman, at Fermilab in 1977, and was the first particle containing a bottom quark to be discovered because it is the lightest that can be produced without additional massive particles. It has a mean lifetime, lifetime of and a mass about in the ground state. See also * Oops-Leon, an erroneously-claimed discovery of a similar particle at a lower mass in 1976. * The particle is the analogous state made from strange quarks. * The particle is the analogous state made from charm quarks. * List of mesons References * * * Mesons Onia Subatomic particles with spin 1 {{particle-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upsilon Peak Upsilon (, ; uppercase Υ, lowercase υ; el, ''ýpsilon'' ) or ypsilon is the 20th letter of the Greek alphabet. In the system of Greek numerals, grc, Υʹ, label=none has a value of 400. It is derived from the phoenician alphabet, Phoenician Waw (letter), waw . Etymology The name of the letter was originally just "υ" (''y;'' also called ''hy'', hence "Hyoid bone, hyoid", meaning "shaped like the letter υ"), but the name changed to "υ ψιλόν" ''u psilon'' 'simple u' to distinguish it from οι, which had come to have the same pronunciation. Pronunciation In early Attic Greek (6th century BCE), it was pronounced (a close back rounded vowel like the English "long o͞o"). In Ancient Greek language, Classical Greek, it was pronounced (a close front rounded vowel), at least until 1030. In Modern Greek, it is pronounced ; in the digraph (orthography), digraphs and , as or ; and in the digraph as . In ancient Greek, it occurred in both Ancient Greek phonology#Vo ... [...More Info...] |
