Study of the clustering structure of ¹⁹B by the use of fragmentation reaction

The clustering structure of neutron dripline nucleus ¹⁹B, which is predicted by the AMD model and the molecular orbital model, is investigated by studying the fragmentation reaction of ¹⁹B. We compare ¹⁹B fragmentation with ¹³B fragmentation in ¹⁹B + ¹⁴N and ¹³B + ¹⁴N reactions at 35 MeV/nucleon by using antisymmetrized molecular dynamics, where ¹³B has no clustering features in its structure. We find that the cluster structure of the ¹⁹B nucleus is reflected in its fragmentation, since more He and Li isotopes are produced in the ¹⁹B fragmentation in comparison with the case in ¹³B fragmentation. Furthermore, we compare the ¹⁹B fragmentation with ¹²C fragmentation in the ¹⁴N-target reaction at 35 MeV/nucleon. In the case of ¹²C fragmentation, the existence of the clustering excited states of ¹²C significantly affects the fragmentation process, since the production of α particles is largely due to fragmentation through these clustering excited states, while in the case of ¹⁹B fragmentation, we cannot find such clustering excited states through which ¹⁹B breaks up into clusters.