Hypernuclear weak decay of 12 Lambda C and 11 Lambda B.
Hypernuclear weak decay of 12 Lambda C and 11 Lambda B.
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12 Lambda C 和 11 Lambda B 的超核弱衰变。
DOI：
10.1103/physrevc.52.2936
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Hashimoto
中科院分区：
文献类型：
--
作者：
Noumi;Ajimura;Ejiri;Higashi;Kishimoto;Gill;Lee;Olin;Fukuda;Hashimoto
测量了由于{sup 12}{sub{lambda}}C和{sup 11}{sub{lambda}}B超核的弱衰变引起的负介子和质子的分支比。负的介子衰减率({Gamma}{sub{pi}{sup{-})，质子诱导的非介子衰减率({Gamma}{sub{italp}})，总的非介子衰减率({Gamma}{sub{tal nm}})，并结合前人对介子{pi}{sup 0}和总衰变率的研究，得出了{lambda}{tal n}{r_row}{tal nn}过程与{lambda}{tal p}{r_row}{tal pn}过程({Gamma}{Sub{tal n}}/{Gamma}{sub{tal p}})的比值。测量的{Gamma}{sub{pi}{sup{-}表明，由于介子的扭曲，泡利阻塞的效果不如预期。我们发现，以自由空间{Lambda}-衰变宽度为单位，{Gamma}{sub{tal nm}}几乎等于1。目前的结果还表明，{Gamma}{sub{italn}}几乎是{Gamma}{sub{italp}}的两倍。这与基于介子交换模型的计算是不一致的，在介子交换模型中，{Gamma}{sub{italn}}被强烈抑制。
The branching ratios of negative pions and protons due to the weak decays of {sup 12}{sub {Lambda}}C and {sup 11}{sub {Lambda}}B hypernuclei were measured. The negative pionic decay rates ({Gamma}{sub {pi}{sup {minus}}}), proton-induced nonmesonic decay rates ({Gamma}{sub {ital p}}), total nonmesonic decay rates ({Gamma}{sub {ital nm}}), and ratios of the {Lambda}{ital n}{r_arrow}{ital nn} process to the {Lambda}{ital p}{r_arrow}{ital pn} process ({Gamma}{sub {ital n}}/{Gamma}{sub {ital p}}) were derived from the present measurements combined with previous studies on the mesonic {pi}{sup 0} and total decay rates. The measured {Gamma}{sub {pi}{sup {minus}}} shows that Pauli blocking is less effective than expected due to pion distortion. We found that {Gamma}{sub {ital nm}} is nearly equal to unity in units of the free-space {Lambda}-decay width. The present results also indicate that {Gamma}{sub {ital n}} is almost twice that of {Gamma}{sub {ital p}}. This is in disagreement with calculations based on meson-exchange models in which {Gamma}{sub {ital n}} is strongly suppressed.