Exotic multi-quark states and baryon spectroscopy workshop

Three methods to search for the two Ξ(1820) states

26 Jun 2024, 16:30

1h

Wolfgang Paul Hörsaal (Universitätsclub Bonn, the University of Bonn)

Speaker

Prof. Eulogio Oset (IFIC, Universidad de Valencia)

Description

The chiral unitary approach produces two states from the pseudoscalar-baryon decuplet interaction in the region of the $\mathrm{\Xi }(1820)$. A recent BESIII experiment on the $\mathrm{\Psi }(3868)\to \overline{\mathrm{\Xi }}{K}^{-}\mathrm{\Lambda }$ showed a clean peak that had an abnormally large width and was interpreted in [1] in terms of the two $\mathrm{\Xi }(1820)$. In view of this, we propose to look at the ${\mathrm{\Omega }}_c\to {\pi }^{+}({\pi }^0,\eta )\pi {\mathrm{\Xi }}^{\ast }$ reaction [2], where the $\pi {\mathrm{\Xi }}^{\ast }$ invariant mass shows an interference pattern of the two resonances. A third reaction $\mathrm{\Psi }(3686)\to {\overline{\Xi }}^{+}{\overline{K}}^0{\Sigma }^{\ast -}$ [3] looks at the ${\overline{K}}^0{\Sigma }^{\ast }$ invariant mass distribution, where due to phase space restrictions, the lower mass $\mathrm{\Xi }(1820)$ is suppressed and the higher mass around 1875 MeV with a larger width shows up clearly.

[1] R.~Molina, W.~H.~Liang, C.~W.~Xiao, Z.~F.~Sun and E.~Oset,
%``Two states for the $\mathrm{\Xi }(1820)$ resonance,''
[arXiv:2309.03618 [hep-ph]].

[2] W.~H.~Liang, R.~Molina and E.~Oset,
%``The ${\mathrm{\Omega }}_c\to {\pi }^{+}({\pi }^0,\eta )\pi {\mathrm{\Xi }}^{\ast }$ reactions and the two $\mathrm{\Xi }(1820)$ states,''
[arXiv:2404.18882 [hep-ph]].

[3] Man-Yu Duan, Jing Song, Wei-Hong Liang and E. Oset

Searching for the two poles of the Ξ(1820) in the $\mathrm{\Psi }(3686)\to {\overline{\Xi }}^{+}{\overline{K}}^0{\Sigma }^{\ast -}$ decay

to be submitted.

Presentation materials

Eulogio_Bonn24.pdf