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We have reanalyzed reaction cross sections of 16N on 12C target. The nucleon density distribution of 16N, especially surface density distribution, was extracted using the modified Glauber model. On the basis of dilute surface densities, the discussion of 15N(n, ��)16N reaction was performed within the framework of the direct capture reaction mechanism. The calculations agreed quite well with the experimental data., 5 pages, 3 figures. arXiv admin note: text overlap with arXiv:0810.3867 by other authors

The measurement of parity-violating (PV) observables in few-nucleon system can shed light on our current understanding of the weak interaction between nucleons. Theoretical models describe the nucleon-nucleon weak interaction at low energies use a series of undetermined parameters. Two parity violating measurements have been considered: the capture of polarized slow neutrons on hydrogen ( + p ? d + ?) at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons ( + d ? n + p) at Shanghai Institute of Applied Physics. The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 ? 10?8. The introduction of both experiments is presented.

The astrophysical reaction rate of 12C(?, ?)16O plays a key role in massive star evolution. However, this reaction rate and its uncertainties have not been well determined yet, especially at T9 = 0.2. The existing results even disagree with each other to a certain extent. In this paper, the E1, E2 and total (E1+E2) 12C(?, ?)16O reaction rates are calculated in the temperature range from T9 = 0.3 to 2 according to all the available cross section data. A new analytic expression of the 12C(?, ?)16O reaction rate is brought forward based on the reaction mechanism. In this expression, each part embodies the underlying physics of the reaction. Unlike previous works, some physical parameters are chosen from experimental results directly, instead of all the parameters obtained from fitting. These parameters in the new expression, with their 3? fit errors, are obtained from fit to our calculated reaction rate from T9 = 0.3 to 2. Using the fit results, the analytic expression of 12C(?, ?)16O reaction rate is extrapolated down to T9 = 0.05 based on the underlying physics. The 12C(?, ?)16O reaction rate at T9 = 0.2 is (8.78 ? 1.52) ? 1015 cm's?1 mol?1. Some comparisons and discussions about our new 12C(?, ?)16O reaction rate are presented, and the contributions of the reaction rate correspond to the different part of reaction mechanism are given. The agreements of the reaction rate below T9 = 2 between our results and previous works indicate that our results are reliable, and they could be included in the astrophysical reaction rate network. Furthermore, we believe our method to investigate the 12C(?, ?)16O reaction rate is reasonable, and this method can also be employed to study the reaction rate of other astrophysical reactions. Finally, a new constraint of the supernovae production factor of some isotopes are illustrated according to our 12C(?, ?)16O reaction rates.

Proton radioactivity has been investigated using the effective liquid drop model with varying mass asymmetry shape and effective inertial coefficient. An effective nuclear radius constant formula replaces the old empirical one in the calculations. The theoretical half-lives are in good agreement with the available experimental data. All the deviations between the calculated logarithmic half-lives and the experimental values are less than 0.8. The root-mean-square deviation is 0.523. Predictions for the half-lives of proton radioactivity are made for elements across the periodic table. From the theoretical results, there are 11 candidate nuclei for proton radioactivity in the region $Z 83$, no nuclei are suggested as probable candidate nuclei for proton radioactivity within the selected range of half-lives studied., 12 pages, 3 figures

Experimental nuclear charge radii for 885 nuclei with N8 and Z8 have been systematically investigated. Results show that the formula for single parameter Z1/3 law is superior to that for the A1/3 law in describing nuclear charge radii. For two-parameter and three-parameter formulae, the Z1/3 law is as good as the A1/3 law. Considering the importance of shell effect and deformations for nuclear charge radii, we add a term including the Casten factor P into the conventional three-parameter formula and thus obtain very good results. The corresponding root-mean-square deviation falls to =0.0273 fm, i.e. reduced by about 50% when compared with the result obtained with the old three-parameter formula. Shell effect can be well reproduced for some elements by adding the Casten factor term. It is shown that the Casten factor plays a key role for nuclear charge radii. The odd-even staggering is a common phenomenon in many nuclear fields. This phenomenon can be observed with nuclear charge radii for most elements. For this reason, we add a term into the formula (10) in this paper. The root-mean-square deviation falls to =0.0266 fm. A five-parameter formula can well reproduce the variation of the nuclear charge radii for most elements. Calculated results are well consistent with the experimental data available. The differences between the experimental nuclear charge radii and the results calculated using the conventional three-parameter formula and the present five-parameter formula for the 885 selected nuclei are presented. A comparison of the formulae mentioned in this paper is given. The present five-parameter formula including the Casten factor P and the odd-even staggering is the best formula to fit available RC data and gives the smallest root-mean-square deviation . Our calculated results may be useful for future experiments.

Reaction and interaction cross sections of 17C on a carbon target have been re-analyzed using the modified Glauber model. The analysis with a deformed Woods-Saxon density/potential suggests a big deformation structure for 17C. The existence of a tail in the density distribution supports the possibility of it being a one-neutron halo structure. Under a deformed core plus a single-particle assumption, analysis shows a dominant d-wave of the valence neutron in 17C.