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Λ hypernuclei: Overview and single-particle nature

Article

Summary

A brief overview ofS=−1 hypernuclei is presented, followed for the main course by a careful, judicious construction of a density-dependent nonlocal Λ-nucleus potential due to Millener, Dover and Gal. The recent Λ level-spectra information obtained from the (π+, K+) experiment at Brookhaven has been combined with that earlier derived from (K, π) reactions in order to determine three parameters which are needed to give a good account of the data and which turn out rather tightly constrained. The analysis yieldsDΛ=(28.0±0.5) MeV for the Λ-nuclear well depth andm*/m=0.78±0.02 for the ratio of Λ effective mass to its free mass. No explicit quark signature,e.g., s-quark partial deconfinement, is found to be necessitated by fitting to these data.

PACS

21.80 - Hypernuclei 

Гиперядра: Обэор и одночастичная природа

Реэюме

Предлагается краткий обэор гиперядер сS=−1. Рассматривается подход, свяэанный с конструированием эависяшего от плотности нелокального потенциала ∧-ядра, который был предложен Миленером, Довером и Галом. Недавняя информация о спектре уровней Λ, полученная иэ (π+, K+)-зксперимента в Брукхеивене, общединяется с информацией, полученной ранее иэ (K, π)-реакций, для определения трех параметров, которые необходимы для общяснения зкспериментальных данных и которые, окаэываются, сильно ограничены. Проведенный аналиэ даетDΛ= (28.0±0.5) МзВ для глубины ямы Λ-ядра иm*/m=0.78±0.02 для отнощения зффективной массы Λ к массе свободного Λ-гиперона. Получается, что ни одна явная кварковая сигнатура не является необходимой для подгонки зтих данных.

Riassunto

Si presenta una breve rassegna degli ipernucleiS=−1, seguita fondamentalmente da un’attenta e prudente costruzione di un potenziale dipendente dalla densità non locale Λ-nucleo dovuto a Millener, Dover e Gal. Le informazioni recenti sugli spettri di livello di Λ ottenuti dall’esperimento (π+, K+) a Broakhaven sono combinate con quelle precedenti derivate dalle reazioni (K, π) per determinare tre parametri che sono necessari per spiegare i dati esaurientemente e risultano abbastanza strettamente vincolati. L’analisi dà come risultatoDΛ=(28.0±0.5) MeV per la profondità del pozzo Λ-nucleare em*/m=0.78±0.02 per il rapporto tra la massa efficace e quella libera di Λ. Approssimando questo dato si trova che nessuna configurazione esplicita di quark, per esempio il deconfinamento parziale dei quark s, si rende necessaria.

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Copyright information

© Società Italiana di Fisica 1989

Authors and Affiliations

  • A. Gal
    • 1
  1. 1.Racah Institute of PhysicsThe Hebrew UniversityJerusalemIsrael

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