Erratum: Is the Nuclear Spin-Orbit Interaction Changing with Neutron Excess? [Phys. Rev. Lett.92, 162501 (2004)]

Abstract

In this Letter, we reported a study of the Snð; tÞ reaction at 40 MeV, on the seven stable, even Sn isotopes, to study the pattern of 11=2 À and 7=2 þ single-particle states as the neutron excess changes. The interpretation of the data relied only on the relative cross sections for these 14 transitions. The absolute cross sections given in Table I, columns 2 and 3, have now been found to be in error. This error has no impact on the rest of the paper, which utilized only the relative values of the cross sections. A numerical error in a measured quantity should, however, be corrected.In the experiment, the cross sections were normalized to the yield for elastic scattering in a monitor detector placed at 9.1 . The collimator in front of the detector had a diameter of 1 mm. In the analysis, it was mistakenly assumed to have had a 1-mm radius.The problem came to light in a recent experiment where the same reaction was studied at 37.5 MeV and significantly different cross sections were found [1], lower by a factor of $3:7 if corrected for a small energy dependence, than those in the Letter. This factor is reasonably constant, showing a rms variation of 8.6% among the 14 transitions. This fluctuation is consistent with the estimated uncertainties from other sources.In all subsequent experiments by our group, utilizing the spectrograph at the Yale tandem facility (e.g., Ref.[2]), a different technique for determining the absolute cross sections was used, a method that did not depend on a monitor at small angles. Instead, the target thicknesses were calibrated by measuring scattering at low bombarding energies and at larger scattering angles. This calibration was done directly with the spectrograph, using the same aperture as in the rest of the measurements. Therefore, the mistake reported here has no effect on the results reported from our subsequent measurements at Yale. *schiffer@anl.gov [1] A. J. Mitchell, Ph.D. thesis, University of Manchester, 2012; the data will be submitted to XUNDL, http://www.nndc.bnl.gov/ xundl/. [2] J. P. Schiffer et al., Phys. Rev. Lett. 108, 022501 (2012).

Chiral three-nucleon forces and the evolution of correlations along the oxygen isotopic chain

“…However, a similar full characterization for exotic isotopes is still lacking. Recent data * c.barbieri@surrey.ac.uk from radioactive beam facilities have put in evidence new phenomena such as shell evolution with changing protonneutron asymmetry [10] and the insurgence of new magic numbers [11][12][13]. From the theoretical point of view, some of these effects have been explained in terms of properties of the tensor interaction [14], and the need for contributions from three-nucleon forces (3NFs) has also been pointed out [15].…”

Tensor interaction in mean-field and density functional theory approaches to nuclear structure

“…We move back to the Skyrme case and analyze another case that has been object of the experimental investigation of Ref. [74]. In Fig.…”

“…One of the main experimental benchmark for these kinds of studies is provided by the data on singleparticle states in N = 82 isotones and Z = 50 isotopes [74]. In Ref.…”

Physics Program at the RIBF with MINOS

“…We proposed to measure the decay energy of 28 O from invariant mass. Y. Kondo from Tokyo Institute of Technology who already investigated the structure of 26 O within the SAMURAI collaboration [24] is spokesperson of this program. Details on these recent studies at the RIBF with the SAMURAI spectrometer and the invariant mass technique are given in this volume in a contribution by Y. Kondo et al.…”

“…These shell modifications have mostly been characterised through systematic studies of low-lying states of unstable nuclei (see examples in [25,26]). A comprehensive picture of the shell evolution as a function of neutron and proton number is not yet reached even though an appreciable number of theoretical works has been performed and several microscopic mechanisms related to fundamental aspects of the nucleonnucleon interaction are currently discussed candidates to be at the origin of shell evolution [27][28][29][30][31].…”