Speaker
Description
The kaonic nuclei, the antikaon($\bar{K}$)-nuclear quasibound states via the strong interaction, is one of the most interesting topics in nuclear hadron physics. Especially, the simplest system, $\bar{K}NN$ nucleus, has been studied both theoretically and experimentally as a first step to understand the structure and properties of the kaonic nuclei.
Among the experimental searches, the peak structure just below the $\bar{K}NN$ threshold was observed in the ${}^{3}\mathrm{He} ( K^{-}, \Lambda p)n$ reaction with $K^{-}$ beam in the J-PARC E15 experiment [1]. A theoretical reaction calculation suggests that the $\bar{K}NN$ nucleus is really produced in the experiment [2]. However, there remains several problems to compare theoretical calculation with experimental data quantitatively. One of the most important problems is incorporating the contribution of two-nucleon absorption process. Although there are various structure calculations of the $\bar{K}NN$ systems, calculations incorporating two-nucleon absorption are not still sufficiently performed.
In this study, we construct a precise model incorporating the contribution of two-nucleon absorption for the $\bar{K}NN$ nucleus in the framework of Faddeev equation. We then calculate the ${}^{3}\mathrm{He} ( K^{-}, \Lambda p)n$ reaction and evaluate the production cross section of the $\bar{K}NN$ nucleus and the $\Lambda p$ invariant mass spectrum. Comparing with the experimental data at J-PARC, we investigate the spin/parity and pole position of the $\bar{K}NN$ nucleus.
[1] T. Yamaga $et \, al$, Phys. Rev. C, $\textbf{102}$, 044002 (2020).
[2] T. Sekihara, E. Oset, A. Ramos, Prog. Theor. Exp. Phys. $\textbf{2016}$, 123D03 (2016).
