Speaker: Kazuo Tsushima (Jefferson Lab)

Title: Binding and Photoproduction of Hypernuclei 
	in The Latest Quark-Meson Coupling Model


Abstract:
First, we discuss the results for hypernucleil obtained by the most 
recent version of the quark-meson coupling (QMC) model, in which the 
effect of the mean scalar field in-medium on the one-gluon exchange 
hyperfine interaction is also included self-consistently. The 
calculations for $\Lambda$ and $\Xi$ hypernuclei are of comparable 
quality to earlier QMC results without the additional parameter needed 
there. Even more significantly, the additional repulsion associated 
with the increased hyperfine interaction in-medium completely changes 
the predictions for $\Sigma$ hypernuclei. Whereas in the earlier work 
they were bound by an amount similar to $\Lambda$ hypernuclei, here 
they are unbound, in qualitative agreement with the experimental 
absence of such states. The equivalent non-relativistic potential felt 
by the $\Sigma$ is repulsive inside the nuclear interior and weakly 
attractive in the nuclear surface, as suggested by the analysis of 
$\Sigma$-atoms.

Next, we discuss the electro/photo-production of hypernuclei based on 
the latest QMC model and the method developed. We compare our results 
with those calculated with the traditional approach, which solely based 
on the hadronic degrees of freedom. This is expected to provide us with 
an opportunity to explore a possible role of the quark degrees of freedom 
in electro/photo-production of hypernuclei.