Emulsion Scanning System for Searching Double-strangeness Nuclei

Abstract

A nuclear emulsion system is a very suitable detector for recognizing very short tracks (∼several µm) of S = −2 nuclei, such as double-Λ hypernuclei, twin-Λ hypernuclei, and Ξ- hypernuclei, because of its submicron spatial resolution. The S = −2 nuclei can provide special experimental information on the Λ-Λ and Ξ--N interactions in the nuclei. The attribute of the S = −2 nuclei is their three vertices around the Ξ- stopping points. The Ξ- hyperons are generated from the quasi-free 'p'(K-, K+)Ξ- reactions. By following the Ξ- tracks plate by plate and observing the Ξ- capture points carefully in the emulsion, S = −2 nuclei can be found. In this work, two methods for emulsion scanning developed to search for S = −2 nuclei are presented, namely, the “track following method” and the “overall scanning method”, as well as the recent results of the event analysis. © 2023 The Korean Physical Society. All rights reserved.