Summary
The spin of the heavy lepton L discovered at SPEAR is discussed. Only if a neutral vector meson X with mass approximately equal to 3.1 GeV and appropriate couplings to electrons and heavy leptons exists, could its spin be 3/2. As a test of the existence of this vector meson a search for the reaction
atW≳7.5 is proposed. A detailed study of the angular distribution of e+e− → L+L− at intermediate energies could also discriminate between spin 1/2 and 3/2. The decay angular distribution of L → πνL as a method of measuring both the heavy-lepton spin and the spin of the corresponding neutrino νL is discussed in a note.
Riassunto
Si discute lo spin del leptone pesante L scoperto a SPEAR. Soltanto se esistesse un mesone vettore X con massa approssimativamente uguale a 3.1 GeV ed accoppiamenti appropriati agli elettroni ed ai leptoni pesanti, il suo spin potrebbe essere 3/2. Come test dell’esistenza di questo mesone vettore si propone la ricerca della reazione
aW≳7.5 GeV. Uno studio dettagliato della distribuzione angolare del processo e+e−→L+L− ad energie intermedie, renderebbe possibile la discriminazione fra spin 1/2 e spin 3/2 per il leptone pesante. In una nota si discute la distribuzione angolare del decadimento L→πv L come metodo di misura dello spin, sia per il leptone pesante che per il suo corrispondente neutrinov L.
Реэюме
Обсуждается спин тяжелого лептона L, обнаруженного в SPEAR. Только если нейтральный векторный меэон X, с массой приблиэительно равной 3.1 ГзB и с соответствуюшими свяэями с злектронами и тяжелыми пептонами, сушествует, то спин тяжелого лептона может быть 3/2. Как проверка сушествования зтого векторного меэона предлагается поиск реакции
приW≳ ≳7.5 ГзB. Подробное исследование углового распределения e+e−→L+L− при промежуточных знергиях также может отделить спины 1/2 и 3/2. В работе обсуждается угловое распределение распада L→πνL, как метод иэмерения спина тяжелых лептонов и спина соответствуюшего нейтрино νL.
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Alles, W., Borelli, V.A. Pair production of heavy leptons and their spin. Nuov Cim A 35, 125–137 (1976). https://doi.org/10.1007/BF02730065
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DOI: https://doi.org/10.1007/BF02730065