IMPRESSIONS OF THE XXIX ZAKOPANE SCHOOL

摘要

It is usual for one participant of this School to be charged with the task of making 'concluding remarks' but having received this honour (or so it seemed six months before the School commenced!) I would prefer instead to give my impressions of the wonderful kaleidoscope of nuclear physics which we have witnessed during the last nine days. I will group what I believe are the key points being addressed by the lecturers into various topics in a rather simplistic approach. Let us begin with perhaps the most fundamental topic: Nuclear Matter Distribution. We have seen a revival of the nuclear Thomas-Fermi model presented by W. Swiatecki. It is remarkable that the new formulation shows that the nuclear compressibility coefficient K has a linear relationship with the surface energy coefficient, allowing the former to be accurately determined. The model parameters are obtained by a fit to experimental data masses, giving an RMS deviation of 0.71 MeV which is comparable to the latest Droplet Model fit. Good agreement with fission barriers (very good for heavy nuclei) is also obtained. Experimental information on nuclear matter distribution was presented by J. Jastrzebski and P. Lubinski, in an elegant experiment performed using LEAR. Here radiochemical measurements are made of mass A - 1 nuclei following bombardment of mass A nuclei with antiprotons. Such nuclei must be survivors of distant annihilation of p + p or n, with the outer nucleon at a sufficiently large radius so that the (on average) 5 pions produced in the annihilation process do not interact with the residual nucleus. These data show evidence for an enhancement of neutrons over protons at large nuclear radii ('neutron halo') which shows a strong inverse correlation with neutron binding energy while showing no correlation with B_p.