Kaon properties and cross sections in nuclear medium

Results for the $\pi + N \to \Lambda, \Sigma + K$ reactions in nuclear matter of Ref. nucl-th/0004011 are presented. To evaluate the in-medium modification of the reaction amplitude as a function of the baryonic density we introduce relativistic, mean-field potentials for the initial, final and intermediate mesonic and baryonic states in the resonance model. These vector and scalar potentials were calculated using the quark meson coupling model. Contrary to earlier work which has not allowed for the change of the cross section in medium, we find that the data for kaon production at SIS energies are consistent with a repulsive $K^+$-nucleus potential.Comment: 5 pages, 3 postscript figures included, uses iopart.cls and iopart10.clo (included), presented by K.T. at the 5th International Conference on Strangeness in Quark Matter, July 20 - 25, 2000, Berkeley, California, to be published in the proceedings, J. Phys. G. An explanation has been added in Sec. 3 with a new figur

Production of Ξ−\Xi^--hypernuclei via the (K−,K+K^-,K^+) reaction in a quark-meson coupling model

We study the production of $\Xi^-$-hypernuclei, $^{12}_{\Xi^{-}}$Be and $^{28}_{\Xi^{-}}$Mg, via the ($K^-,K^+$) reaction within a covariant effective Lagrangian model, employing the bound $\Xi^-$ and proton spinors calculated by the latest quark-meson coupling model. The present treatment yields the $0^\circ$ differential cross sections for the formation of simple s-state $\Xi^-$ particle-hole states peak at a beam momentum around 1.0 GeV/c with a value in excess of 1 $\mu$b.Comment: Accepted version with miner changes, 4 pages, 2 figures, Presented at the 20th International IUPAP Conference on Few-Body Problems in Physics, 20 - 25 August, 2012, Fukuoka, Japa

Λc+\Lambda^+_c- and Λb\Lambda_b-hypernuclei

$\Lambda^+_c$- and $\Lambda_b$-hypernuclei are studied in the quark-meson coupling (QMC) model. Comparisons are made with the results for $\Lambda$-hypernuclei studied in the same model previously. Although the scalar and vector potentials felt by the $\Lambda$, $\Lambda_c^+$ and $\Lambda_b$ in the corresponding hypernuclei multiplet which has the same baryon numbers are quite similar, the wave functions obtained, e.g., for $1s_{1/2}$ state, are very different. The $\Lambda^+_c$ baryon density distribution in $^{209}_{\Lambda^+_c}$Pb is much more pushed away from the center than that for the $\Lambda$ in $^{209}_\Lambda$Pb due to the Coulomb force. On the contrary, the $\Lambda_b$ baryon density distributions in $\Lambda_b$-hypernuclei are much larger near the origin than those for the $\Lambda$ in the corresponding $\Lambda$-hypernuclei due to its heavy mass. It is also found that level spacing for the $\Lambda_b$ single-particle energies is much smaller than that for the $\Lambda$ and $\Lambda^+_c$.Comment: Latex, 14 pages, 4 figures, text was extended, version to appear in Phys. Rev.

Properties of charmed and bottom hadrons in nuclear medium: Results for Λc+\Lambda_c^+ and Λb\Lambda_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 $\Lambda^+_c$ and $\Lambda_b$ hypernuclei are studied quantitatively. Comparisons are made with the results for the $\Lambda$ hypernuclei studied previously in the same approach. It is shown that although the scalar and vector potentials for the $\Lambda$, $\Lambda_c^+$ and $\Lambda_b$ 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 $\Lambda^+_c$ probability density distribution in $^{209}_{\Lambda^+_c}$Pb is much more pushed away from the center than that for the $\Lambda$ in $^{209}_\Lambda$Pb due to the Coulomb force. On the contrary, the $\Lambda_b$ probability density distributions in $\Lambda_b$ hypernuclei are much larger near the origin than those for the $\Lambda$ in the $\Lambda$ hypernuclei due to its heavy mass. A possibility of $B^-$ nuclear bound (atomic) states is also briefly discussed.Comment: 12 pages, 7 embedded figures, uses PTP-Tex environment (all included), Invited talk presented at YITP-RCNP Workshop on "Chiral Restoration in Nuclear Medium", October 7-9, 2002, YITP Kyoto University, Japan, to be published in the proceeding