Interpretation of a double hypernucleus event

Arguments are put forward to suggest that a double hypernucleus event, recently reported by Aoki et al. as either _ΛΛ¹⁰Be or _ΛΛ¹³B, should be interpreted as _ΛΛ¹³B. It is proposed that the formation of _ΛΛ¹³B occurs sequentially via an intermediate excited state of _ΛΛ¹⁴C, which decays by proton emission: Ξ^-+¹⁴N→n+_ΛΛ¹⁴C*, _ΛΛ¹⁴C*→p+_ΛΛ¹³B. Moreover, it is shown that particular excited states are favored in the Ξ^- hyperon capture process. The binding energy of the two Λ hyperons in _ΛΛ¹³B is B_ΛΛ=27.5±0.7 MeV, corresponding to an attractive s_Λ² matrix element ΔB_ΛΛ=4.8±0.7 MeV, in good agreement with values of ΔB_ΛΛ obtained from previous events.