Information and perspective for doubly-strange hypernuclei with nuclear emulsion detector

¹ Faculty of Education, Gifu University, 501-1193 Gifu, Japan
² Graduate School of Engineering, Gifu University, 501-1193 Gifu, Japan

^* e-mail: nakazawa.kz@gmail.com

Published online: 9 November 2022

Abstract

The study on doubly-strange hypernuclei has been performed with nuclear emulsion detector at KEK-PS and J-PARC for 30 years. Detected 47 candidate events of doubly-strange hypernuclei show characteristics for the Λ-Λ and Ξ-N interactions. The Λ-Λ interaction is weakly at-tractive and the binding energy of two Λ hyperons to nuclei shows linear dependence on the mass number of a nucleus. The Ξ^– hyperon is found to be bound by the ¹⁴N nucleus, forming the _Ξ¹⁵C hypernucleus, with larger energy than that given by Coulomb force. Also, the level scheme of the Ξ^– hyperon in the _Ξ¹⁵C hypernucleus can be seen. With the light source of hard X-ray instead of an optical microscope, since it will enable to count grains constituting tracks in the emulsion, charge recognitions of light nuclei, especially H⁺ and He²⁺, can be possible. This would work effectively in determining the nuclides of doubly-strange hypernuclei. The ‘overall-scanning method’ to scan whole volume of the emulsion sheets will allow to detect nearly 1 x 10³ events of doubly-strange hypernuclei, which is the expected number recorded in the emulsion of the E07 experiment, with machine learning in the near future.