Properties of charmed and bottom hadrons in nuclear medium : Results for Λ + c and Λ b hypernuclei

This reports our recent studies on changes in properties of heavy hadrons containing at least a charm or a bottom quark in nuclear matter, and that the results for the Λ + c and Λ b hypernuclei are studied quantitatively. Comparisons are made with the results for the Λ hypernuclei studied previously in the same approach. It is shown that although the scalar and vector potentials for the Λ, Λ + c and Λ b in the hypernuclei multiplet with the same baryon numbers are quite similar, the wave functions obtained, e.g., for 1s 1/2 state, are very different. The Λ + c probability density distribution in 209 Λ + c Pb is much more pushed away from the center than that for the Λ in 209 Λ Pb due to the Coulomb force. On the contrary, the Λ b probability density distributions in Λ b hypernuclei are much larger near the origin than those for the Λ in the Λ hypernuclei due to its heavy mass. A possibility of B − nuclear bound (atomic) states is also briefly discussed. Partial restoration of chiral symmetry in nuclear medium is now one of the most important and interesting issues in nuclear and hadronic physics. There is no doubt that it plays a crucial role in understanding numerous phenomenon involving many particles, such as relativistic heavy ion collisions, structure and properties of neutron stars, and those of heavy nuclei, and so on. Coverage of the issue is too vast to cite complete references. This workshop is also one of the activities to understand and study the role of chiral restoration in nuclear medium. Our focus is on the consequences of partial restoration of chiral symmetry in nuclear medium, on the properties of heavy hadrons containing at least a charm or a bottom quark. We report the results on the changes in properties of heavy hadrons in nuclear matter, 1) and results for the Λ + c and Λ b hypernuclei studied quantitatively. 2) In spite of the importance, there are studied for heavy mesons with charm only a limited number (J/Ψ 3), 4) and D(D) 5)) in nuclear matter using the QCD sum rule. However, there seem to exist no studies for heavy baryons with a charm or a bottom quark, except for the studies made recently. 1), 2) Furthermore, in considering recent experiments on high energy heavy ion collisions, to study …