Sigma Exchange in the Nonmesonic Decays of Light Hypernuclei and Violation of the Delta I=1/2 Rule

Abstract

Nonmesonic weak decays of s-shell hypernuclei are analyzed in microscopic models for the Lambda N to NN weak interaction. A scalar-isoscalar meson, sigma, is introduced and its importance in accounting the decay rates, n/p ratios and proton asymmetry is demonstrated. Possible violation of the Delta I=1/2 rule in the nonmesonic weak decay of Lambda is discussed in a phenomenological analysis and several useful constraints are presented. The microscopic calculation shows that the current experimental data indicate a large violation of the Delta I=1/2 rule, although no definite conclusion can be derived due to large ambiguity of the decay rate of {^4_Lambda H}.

arXiv comment13 pages, 5 figures

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Cited by in corpus (16)

• Strangeness in nuclear physics
• Strangeness nuclear physics: a critical review on selected topics
• Single and double coincidence nucleon spectra in the weak decay of Lambda hypernuclei
• Two-pion-exchange in the non-mesonic weak decay of $\Lambda$-hypernuclei
• Weak decays of 4He-Lambda
• Asymmetry parameter for nonmesonic hypernuclear decay
• $\sigma$ meson exchange effect on nonmesonic hypernuclear weak decay observables
• Current constraints on the EFT for the ΛN --> N N transition
• s-Wave Approximation for Asymmetry in Nonmesonic Decay of Finite Hypernuclei
• Nonmesonic weak decay spectra of ${}_{\Lambda }^4$He
• Relationships between nonmesonic-weak-decays in different hypernuclei
• Microscopic approach to the proton asymmetry in the non-mesonic weak decay of Lambda-hypernuclei
• Nonmesonic weak decay spectra of light hypernuclei
• Relativistic model for the nonmesonic weak decay of single-lambda hypernuclei
• Effects of $\Lambda \Lambda -\Xi N$ mixing in the decay of $S=-2$ hypernuclei
• Delayed clusters accompanying nonmesonic weak decay of the $\Lambda$-hypernuclei: a clue to nonleptonic processes