Speaker
Description
Recent results and future plans at J-PARC on baryon-baryon interaction studies are presented.
We recently observed several new events of double-strange hypernuclei in the emulsion-counter hybrid experiment (E07) [1]. Observed events indicate a rather deep binding energy of $\Xi$ in the $^{14}$N nucleus. One of the events is interpreted as a bound state of $\Xi$ in the nuclear 0s orbit, suggesting that the $\Xi$$N$-$\Lambda$$\Lambda$ interaction is unexpectedly weak [2]. Further $\Xi$-hypernuclear studies by missing mass spectroscopy of the ($K^-,K^+$) reaction (E70) will be conducted soon.
We also successfully carried out a high-statistics $\Sigma^\pm$-$p$ scattering experiment (E40) [3]. In the $\Sigma^+ p$ channel, the obtained cross section was converted to the phase shift, showing that the $\Sigma^+ p$ interaction has a much stronger repulsive core than the $NN$ interaction, which is interpreted as a result of Pauli principle in the quark level [4].
In the future, we plan to investigate the $\Lambda N N$ three-body force via high-resolution $\Lambda$-hypernuclear spectroscopy. Together with high quality $\Lambda$-$p$ scattering experiments, it allows us to solve the “hyperon puzzle” in neutron stars. Such studies will be performed using new secondary beam lines in the J-PARC Hadron Facility extension project [5].
[1] H. Ekawa et al., Prog. Theor. Exp. Phys. 2019 (2019) 021D02;
S. H. Hayakawa et al., Phys. Rev. Lett. 126 (2021) 062501.
[2] M. Yoshimoto et al., Prog. Theor. Exp. Phys. 2021 (2021) 7.
[3] K. Miwa et al., Phys. Rev. C 104 (2021) 045204; Phys. Rev. Lett. 128 (2022) 072501.
[4] T. Nanamura et al., Prog. Theor. Exp. Phys. 2022 (2022) 093D01,
[5] K. Aoki et al., arXiv: 2110.04462 [nucl-ex] (2021).
