Statistical double $\Lambda$ hypernuclear formation from ${\Xi }^{-}$ absorption at rest in light nuclei

Abstract

We investigate double $\Lambda$ hyperfragment formation from the statistical decay of double $\Lambda$ compound nuclei produced in the ${\Xi }^{-}$ absorption at rest in light nuclei, ${}^{12}\mathrm{C}$, ${}^{14}\mathrm{N}$ and ${}^{16}\mathrm{O}$. We examine the target and the $\Lambda \Lambda$ bond energy dependence of the double $\Lambda$ hyperfragment formation probabilities, especially of those double hypernuclei observed in experiments. For the ${}^{12}\mathrm{C}$ (${}^{14}\mathrm{N}$) target, the formation probabilities of ${}_{\Lambda \Lambda }^6\mathrm{He}$ and ${}_{\Lambda \Lambda }^{10}\mathrm{Be}$ (${}_{\Lambda \Lambda }^{13}\mathrm{B}$) are found to be reasonably large as they are observed in the KEK-E373 (KEK-E176) experiment. By comparison, for ${}^{16}\mathrm{O}$ target, the formation probability of ${}_{\Lambda \Lambda }^{11}\mathrm{Be}$ is calculated to be small with $\Delta B_{\Lambda \Lambda }$ consistent with the Nagara event. We also evaluate the formation probability of ${}_{\Lambda \Lambda }^5\mathrm{H}$ from a ${\Xi }^{-}$-${}^6\mathrm{He}$ bound state, ${}_{\Xi }^7\mathrm{H}$.

Comments: 19 pages, 10 figures (revision is made in v3)