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

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