A benchmark experiment on (208)Pb shows that polarized proton inelastic scattering at very forward angles including 0° is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted E1 polarizability leads to a neutron skin thickness r(skin) = 0.156(-0.021)(+0.025) fm in (208)Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars.

Kinematically complete measurements for Coulomb dissociation of n Li into 9 Li + 2« were made at 28 MeV/nucleon. The n-n correlation function suggests a large source size for the two-neutron emission. The electromagnetic excitation spectrum of n Li has a peak, as anticipated in low-energy dipole resonance models, but a large post-breakup Coulomb acceleration of the 9 Li fragment is observed, indicating a very short lifetime of the excited state and favoring direct breakup as the dissociation mechanism.

The electric dipole strength distribution in 48 Ca between 5 and 25 MeV has been determined at RCNP, Osaka, from proton inelastic scattering experiments at forward angles. Combined with photoabsorption data at higher excitation energy, this enables the first extraction of the electric dipole polarizability αD( 48 Ca) = 2.07(22) fm 3 . Remarkably, the dipole response of 48 Ca is found to be very similar to that of 40 Ca, consistent with a small neutron skin in 48 Ca. The experimental results are in good agreement with ab initio calculations based on chiral effective field theory interactions and with state-of-the-art density-functional calculations, implying a neutron skin in 48 Ca of 0.14 − 0.20 fm.Introduction.-The equation of state (EOS) of neutronrich matter governs the properties of neutron-rich nuclei, the structure of neutron stars, and the dynamics of corecollapse supernovae [1,2]. The largest uncertainty of the EOS at nuclear densities for neutron-rich conditions stems from the limited knowledge of the symmetry energy J, which is the difference of the energies of neutron and nuclear matter at saturation density, and the slope of the symmetry energy L, which is related to the pressure of neutron matter. The symmetry energy also plays an important role in nuclei, where it contributes to the formation of neutron skins in the presence of a neutron excess. Calculations based on energy density functionals (EDFs) pointed out that J and L can be correlated with isovector collective excitations of the nucleus such as pygmy dipole resonances [3] and giant dipole resonances (GDRs) [4], thus suggesting that the neutron skin thickness, the difference of the neutron and proton root-mean-square radii, could be constrained by studying properties of collective isovector observables at low energy [5]. One such observable is the nuclear electric dipole polarizability α D , which represents a viable tool to constrain the EOS of neutron matter and the physics of neutron stars [6][7][8][9][10][11].While correlations among α D , the neutron skin and the symmetry energy parameters have been studied extensively with EDFs [12][13][14][15][16], only recently have ab initio calculations based on chiral effective field theory (χEFT) interactions successfully studied such correlations in medium-mass nuclei [17,18]. By using a set of chiral two-plus three-nucleon interactions [19,20] and

We survey odd-even nuclear binding energy staggering using density functional theory with several treatments of the pairing interaction including the BCS, Hartree-Fock-Bogoliubov, and the HartreeFock-Bogoliubov with the Lipkin-Nogami approximation. We calculate the second difference of binding energies and compare with 443 measured neutron energy differences in isotope chains and 418 measured proton energy differences in isotone chains. The particle-hole part of the energy functional is taken as the SLy4 Skyrme parametrization and the pairing part of the functional is based on a contact interaction with possible density dependence. An important feature of the data, reproduced by the theory, is the sharp gap quenching at magic numbers. With the strength of the interaction as a free parameter, the theory can reproduce the data to an rms accuracy of about 0.25 MeV. This is slightly better than a single-parameter phenomenological description but slightly poorer than the usual two-parameter phenomenological form C/A α . The following conclusions can be made about the performance of common parametrization of the pairing interaction: (i) there is a weak preference for a surface-peaked neutron-neutron pairing, which might be attributable to many-body effects; (ii) a larger strength is required in the proton pairing channel than in the neutron pairing channel; (iii) pairing strengths adjusted to the well-known spherical isotope chains are too weak to give a good overall fit to the mass differences.

A computer program is presented aiming at the calculation of bound and continuum states, reduced transition probabilities, phase-shifts, photo-disintegration cross sections, radiative capture cross sections, and astrophysical S-factors, for a two-body nuclear system. The code is based on a potential model of a Woods-Saxon, a Gaussian, or a M3Y, type. It can be used to calculate nuclear reaction rates in numerous astrophysical scenarios.