NEUTRON HALOS IN HEAVY NUCLEI-RELATIVISTIC MEAN-FIELD APPROACH

Assuming a simple spherical relativistic mean field model of the nucle us, we estimate the width of the antiproton-neutron annihilation (Gamm a(n)) and the width of antiproton-proton (Gamma(p)) annihilation, in a n antiprotonic atom system. This allows us to determine the halo facto r f, which is then discussed in the context of experimental data obtai ned in measurements recently done on LEAR utility at CERN. Another qua ntity which characterizes the deviation of the average nuclear densiti es ratio from the corresponding ratio of the homogeneous densities is introduced too. It was shown that it is also a good indicator of the n eutron halo. The results are compared to experimental data as well as to the data of the simple liquid droplet model of the nuclear densitie s. The single particle structure of the nuclear density tail is discus sed also.