Coulomb breakup effects on the elastic cross section of 6^6He+209^{209}Bi scattering near Coulomb barrier energies

We accurately analyze the $^6$He+$^{209}$Bi scattering at 19 and 22.5 MeV near the Coulomb barrier energy, using the continuum-discretized coupled-channels method (CDCC) based on the $n$+$n$+$^4$He+$^{209}$Bi four-body model. The three-body breakup continuum of $^6$He is discretized by diagonalizing the internal Hamiltonian of $^6$He in a space spanned by the Gaussian basis functions. The calculated elastic and total reaction cross sections are in good agreement with the experimental data, while the CDCC calculation based on the di-neutron model of $^6$He, i.e., the $^2n$+$^{4}$He+$^{209}$Bi three-body model, does not reproduce the data.Comment: 5 pages, 5 figures, uses REVTeX 4, submitted to Phys. Rev.

Determination of S17 from 8B breakup by means of the method of continuum-discretized coupled-channels

The astrophysical factor for 7Be(p,\gamma)8B at zero energy, S17(0), is determined from an analysis of 208Pb(8B, p+7Be)208Pb at 52 MeV/nucleon by means of the method of continuum-discretized coupled-channels (CDCC) taking account of all nuclear and Coulomb breakup processes. The asymptotic normalization coefficient (ANC) method is used to extract S17(0) from the calculated breakup-cross-section. The main result of the present paper is S17(0)=20.9 +2.0/-1.9 eV b. The error consists of 8.4% experimental systematic error and the error due to the ambiguity in the s-wave p-7Be scattering length. This value of S17(0) differs from the one extracted with the first-order perturbation theory including Coulomb breakup by dipole transitions: 18.9 +/- 1.8 eV b. It turns out that the difference is due to the inclusion of the nuclear and Coulomb-quadrupole transitions and multi-step processes of all-order in the present work. The p-7Be interaction potential used in the CDCC calculation is also used in the ANC analysis of 7Be(p,\gamma)8B. The value of S17(0)=21.7 +0.62/-0.55 eV b obtained is consistent with the previous one obtained from a precise measurement of the p-capture reaction cross section extrapolated to zero incident energy, S17(0)=22.1 +/- 0.6 (expt) +/- 0.6 (theo) eV b, where (theo) stands for the error in the extrapolation. Thus, the agreement between the values of S17(0) obtained from direct 7Be(p,\gamma)8B and indirect 8B-breakup measurements is significantly improved.Comment: 13 pages, 9 figures, published in PR

Kaon-nucleon interaction in the extended chiral SU(3) quark model

The chiral SU(3) quark model is extended to include the coupling between the quark and vector chiral fields. The one-gluon exchange (OGE) which dominantly governs the short-range quark-quark interaction in the original chiral SU(3) quark model is now nearly replaced by the vector-meson exchange. Using this model, the isospin I=0 and I=1 kaon-nucleon S, P, D, F wave phase shifts are dynamically studied by solving the resonating group method (RGM) equation. Similar to those given by the original chiral SU(3) quark model, the calculated results for many partial waves are consistent with the experiment, while there is no improvement in this new approach for the P_{13} and D_{15} channels, of which the theoretical phase shifts are too much repulsive and attractive respectively when the laboratory momentum of the kaon meson is greater than 300 MeV.Comment: 19 pages, 16 figures. Accepted by Phys. Rev.

Light Ξ\Xi hypernuclei in four-body cluster models

Detailed structure calculations in $^{\: 12}_{\Xi^-}$Be, $^{\: 5}_{\Xi^-}$H, $^{\: 9}_{\Xi^-}$Li, $^{\: 7}_{\Xi^-}$H and $^{\:10}_{\Xi^-}$Li are performed within the framework of the microscopic two-, three- and four-body cluster models using the Gaussian Expansion Method.Comment: 14 pages, 19 figures. To be published in Phys. Rev.

New treatment of breakup continuum in the method of continuum discretized coupled channels

A new method of pseudo-state discretization is proposed for the method of continuum discretized coupled channels (CDCC) to deal with three-body breakup processes. We propose real- and complex-range Gaussian bases for the pseudo-state wave functions, and show that they form in good approximation a complete set in the configuration space which is important for breakup processes. Continuous S-matrix elements are derived with the approximate completeness from discrete ones calculated by CDCC. Accuracy of the method is tested quantitatively for two realistic examples, d+$^{58}$Ni scattering at 80 MeV and $^{6}$Li+$^{40}$Ca scattering at 156 MeV with the satisfactory results. Possibility of application of the method to four-body breakup processes is also discussed.Comment: 10 pages, 14 Postscript figures, uses REVTeX 4, submitted to Phys. Rev.

Gaussian expansion approach to Coulomb breakup

An accurate treatment of Coulomb breakup reactions is presented by using both the Gaussian expansion method and the method of continuum discretized coupled channels. As $L^2$-type basis functions for describing bound- and continuum-states of a projectile, we take complex-range Gaussian functions, which form in good approximation a complete set in a large configuration space being important for Coulomb-breakup processes. Accuracy of the method is tested quantitatively for $^{8}{\rm B}+^{58}$Ni scattering at 25.8 MeV.Comment: 4 pages, 4 figures; typos removed, a reference added for introduction and submitted to Phys. Rev. C as a brief repor