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Canton et al. Reply: In the preceding Comment, Fortune and Sherr (FS) agree with our prediction on the existence of three narrow odd-parity resonances in 15 F, finding them within the same excitation range and having the same spinparity and level ordering. Their argument, based upon a very different approach from ours, concerns some differences in the resonance centroids and widths. They conclude that the energies and widths of these narrow resonances might be considerably different from what we found.FS comment first on the energy centroids of the three narrow resonances. As the relevant question has been addressed in our Letter [1], we only remind readers that the energies of these narrow states are shifted higher from the results obtained by including the pure Coulomb effects to the mirror states in 15 C. The central term of the p-14 O nuclear potential required a shift of 0.8 MeV (with respect to the n-14 C potential) to find the appropriate centroid and width values of the 1 2

We seek a measure of the neutron density of 208 Pb from analyses of intermediate energy nucleon elastic scattering. The pertinent model for such analyses is based on coordinate space nonlocal optical potentials obtained from model nuclear ground state densities. Those potentials give predictions of integral observables and of angular distributions which show sensitivity to the neutron density. When compared with experiment, and correlated with analyses of electron scattering data, the results suggest that 208 Pb has a neutron skin thickness ∼ 0.17 fm.

Data for the scattering of 6He, 8He, 9Li, and 11Li from hydrogen are analyzed within a fully microscopic folding model of proton-nucleus scattering. Current data suggest that of these only 11Li has a noticeable halo. For 6He, we have also analysed the complementary reaction 6Li(gamma,pi)6He(gs). The available data for that reaction support the hypothesis that 6He may not be a halo nucleus. However, those data are scarce and there is clearly a need for more to elicit the microscopic structure of 6He.Comment: 18 pages, 8 figures (added 4 figures), added reference. Version accepted for publication in Phys. Rev.

A multi-channel algebraic scattering theory, to find solutions of coupled-channel scattering problems with interactions determined by collective models, has been structured to ensure that the Pauli principle is not violated. By tracking the results in the zero coupling limit, a correct interpretation of the sub-threshold and resonant spectra of the compound system can be made. As an example, the neutron-12 C system is studied defining properties of 13 C to 10 MeV excitation. Accounting for the Pauli principle in collective coupled-channels models is crucial to the outcome. 25.40.Dn;25.40.Ny;28.20.Cz At energies above 25 MeV, by using optical potentials formed by full folding effective two-nucleon interactions with microscopic (nucleon based) descriptions of the target structure, the importance of treating the Pauli principle has been well established [1]. However, in the domain of low-energy nucleon scattering for which an explicit coupled-channels theory of scattering is essential, the significance of Pauli exclusion effects has not been well defined. Many coupled-channels codes are available, some of which perform phenomenological collective-model calculations searching on parameter values of the chosen function forms to find a best fit to experimental data. But while it has long been known that any such models violate the Pauli principle [2,3], quantification of that violation is lacking.To study the effects of the Pauli principle in a macroscopic (collective model) approach is not a trivial task. In a recent publication [4], the orthogonalizing pseudopotential (OPP) method [5,6] was generalized to treat this problem. That was a small though important part of the full theoretical framework of the multi-channel algebraic scattering (MCAS) theory of scattering [4]. Therein the OPP was used in finding the spectra, bound and resonance properties, of 13 C. However, implications of the role of the Pauli principle in collective model coupledchannel calculations arising from the use of the OPP was not discussed. Such is a purpose of this letter. Another is that the method could be pertinent for any study requiring coupled channel solutions of quantal systems involving fermions. As the example, we study the effects introduced by the Pauli principle in collective, geometrical-type, models for low-energy nucleon-nucleus processes that can be characterized from the spectrum of the compound nucleus. That spectrum includes the states that lie below the nucleon-nucleus threshold and in the continuum as revealed by the narrow and broad resonances that lie upon a smooth but energy dependent background of the elastic scattering cross section. This can be done in a systematic and self-consistent way since the MCAS approach facilitates such a determination of the sub-threshold bound states and resonances of the compound nucleus. This theory, with which one solves the coupled-channel Lippmann-Schwinger (LS) equations for the nucleon-nucleus system considered, is built upon sturmian expansions of an interaction matrix of potent...