Possible Experimental Evidence of a Moderate Proton Halo in29S

Abstract

The total reaction cross sections (TRCSs) of 29S+28Sihave been measured at intermediate energies. An obvious enhancement inTRCS of 29S is observed as compared with its neighbouring nuclei.The TRCSs of 29S+28Si are calculated with the modifiedGlauber theory in the optical limit and few-body approaches. Thedifferent factor d as a possible measure of halo appearance isdeduced from the experimental and theoretical data. It is well acceptedthat 27P is a proton halo nucleus. Although not as anomalous as27P, the different factor d of 29S is obviouslylarger than that of its neighbouring isotones of N = 13. Thisresult indicates that a moderate proton halo may exist in 29Snucleus. We calculate the total reaction cross sections for 29Swith the modified Glauber theory as a function of incident energy andcompare the results with those for 27Si which is a core nucleusof 29S. The measured TRCSs of 27Si+28Si can bedescribed to be satisfactory by the modified Glauber theory of theoptical limit approach. Although a diffused nuclear densitydistribution is used, the theories still inadequately predict theexperimental TRCSs of 29S+28Si, which further indicatesthe possibility of proton halo in 29S.