Has J-PARC E07 observed a ${\Xi }_{1s}^{-}$ nuclear state?

Abstract

The Strangeness $\mathcal{S}=-2$ J-PARC E07 emulsion experiment published recently two new ${\Xi }^{-}$--${}^{14}$N capture events, IRRAWADDY and IBUKI, identified by observing weak-decay sequences of pairs of single-$\Lambda$ hypernuclei and interpreted as ${\Xi }_{1s}^{-}$ and ${\Xi }_{1p}^{-}$ nuclear bound states, respectively, with binding energies $B_{{\Xi }^{-}}^{1s}$=6.27$\pm$0.27 MeV and $B_{{\Xi }^{-}}^{1p}$=1.27$\pm$0.21 MeV. ${\Xi }^{-}$ capture events in emulsion play a major role in determining the $\Xi$-nuclear and the $\Lambda \Lambda$ potential strengths. Here we question the assignment of a ${\Xi }_{1s}^{-}$ nuclear bound state to IRRAWADDY and offer an alternative assignment as a near-threshold ${\Xi }_{1p}^0$--${}^{14}$C nuclear bound state, slightly admixed with a ${\Xi }_{1p}^{-}$--${}^{14}$N nuclear bound state component corresponding to IBUKI. We also question using IBUKI's $B_{{\Xi }^{-}}^{1p}$ value as is to determine the $\Xi$-nuclear potential depth. Altogether, ${\Xi }^{-}$ capture events in ${}^{12}$C and ${}^{16}$O should prove less ambiguous than in ${}^{14}$N.

arXiv comment11 pages, 2 figures, 4 tables, v1: as submitted for publication, v2: slightly extended to match PLB published version

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Cited by in corpus (5)

• Constraining a relativistic mean field model using neutron star mass-radius measurements II: Hyperonic models
• Density-dependent relativistic mean-field model for ${\Xi }^{-}$ hypernuclei
• Impact of $\Xi$-Hypernuclear Constraints on Relativistic Equation of State and Properties of Hyperon Stars
• Deciphering ${\Xi }^{-}$ capture events in light emulsion nuclei
• Theoretical study of the $\Xi \alpha$ correlation function