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Charmed baryons are a category of composite particles comprising all baryons made of at least one charm quark. Since their first observation in the 1970s, a large number of distinct charmed baryon states have been identified. Observed charmed baryons have masses ranging between and . In 2002, the SELEX collaboration, based at Fermilab published evidence of a doubly charmed baryon (), containing two charm quarks) with a mass of ~, but has yet to be confirmed by other experiments. One triply charmed baryon () has been predicted but not yet observed. ==Nomenclature== (詳細はquark content and isospin. The naming follows the rules established by the Particle Data Group. * Charmed baryons composed of one charm quark and two up, one up and one down, or two down quarks are known as charmed Lambdas (, isospin 0), or charmed Sigmas (, isospin 1). * Charmed baryons of isospin composed of one charm quark, and one up or down quark are known as charmed Xis () and all have isospin . * Charmed baryons composed of one charm quark and no up or down quarks are called charmed Omegas () and all have isospin 0. * Charmed baryons composed of two charm quarks and one up or down quark are called double charmed Xis () and all have isospin ). * Charmed baryons composed of two charm quarks and no up or down quarks are called double charmed Omega () and all have isospin 0. * Charmed baryons composed of three charm quarks are called triple charmed Omegas (), and all have isospin 0. Charge is indicated with superscripts. Heavy quark (bottom, charm, or top quarks) content is indicated by subscripts. For example, a is made of one bottom, one charmed quark, and it can be deduced from the charge of the charm (+e) and bottom quark (−e) that the other quark must be an up quark (+e). Sometimes asterisks or primes are used to indicate a resonance. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Charmed baryons」の詳細全文を読む スポンサード リンク
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