Novel Weak Decays in Doubly Strange Systems

Abstract

The strangeness-changing ($\Delta S=1$) weak baryon-baryon interaction is studied through the nonmesonic weak decay of double-$\Lambda$ hypernuclei. Besides the usual nucleon-induced decay $\Lambda N\to NN$ we discuss novel hyperon-induced decay modes $\Lambda \Lambda \to \Lambda N$ and $\Lambda \Lambda \to \Sigma N$. These reactions provide unique access to the exotic $\Lambda \Lambda$K and $\Lambda \Sigma$K vertices which place new constraints on Chiral Pertubation Theory ($\chi$PT) in the weak SU(3) sector. Within a meson-exchange framework, we use the pseudoscalar $\pi ,\eta ,K$ octet for the long-range part while parametrizing the short-range part through the vector mesons $\rho ,\omega ,K^{\ast }$. Realistic baryon-baryon forces for the $S=0,-1$ and -2 sectors account for the strong interaction in the initial and final states. For ${}_{\Lambda \Lambda }^6$He the new hyperon-induced decay modes account for up to 4% of the total nonmesonic decay rate. Predictions are made for all possible nonmesonic decay modes.

19 pages, 2 ps figures, 9 tables

References in corpus (1)

• Meson exchange in the weak decay of Lambda hypernuclei and the Gamma_n/Gamma_p ratio

Cited by in corpus (10)

• Weak Decay of Lambda Hypernuclei
• Strangeness nuclear physics: a critical review on selected topics
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• Bulk viscosity in neutron stars with hyperon cores
• What Does Free Space Lambda-Lambda Interaction Predict for Lambda-Lambda Hypernuclei?
• Hyperonic mixing in five-baryon double-strangeness hypernuclei in a two-channel treatment
• The $\Lambda \Lambda \to YN$ Weak Transition in Double-$\Lambda$ Hypernuclei
• Models of the Nonmesonic Weak Decay
• Nonmesonic Weak Decay of $\Lambda$ Hypernuclei: The Three--Nucleon Induced Mode
• Effects of $\Lambda \Lambda -\Xi N$ mixing in the decay of $S=-2$ hypernuclei