
01-01-2010, 04:56
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تاريخ التسجيل: Jan 2007
المشاركات: 4,157
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رد: ساعدوني أثابكم الله
In physics, and specifically, particle physics, isospin (isotopic spin, isobaric spin) is a quantum number related to the strong interaction. This term was derived from isotopic spin, but the term is confusing as two isotopes of a nucleus have different numbers of nucleons; in contrast, rotations of isospin maintain the number of nucleons. Nuclear physicists prefer isobaric spin, which is more precise in meaning. Isospin symmetry is a subset of the flavour symmetry seen more broadly in the interactions of baryons and mesons. Isospin symmetry remains an important concept in particle physics, and a close examination of this symmetry historically led directly to the discovery and understanding of quarks and of the development of Yang-Mills theory.
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