Background of Existence of the Two Low-Lying Adjacent 4^(+) Narrow Resonances in ^(16)O Nucleus and Other 4-Boson Systems

Based on an analysis of the inherent nodal structures of wave functions of 4-boson systems,we found that the internal energy of the 4_(1)^(+) state should be lower because its structure can be optimized without suffering a strong constraint arising from symmetry(while other 1≤L≤3 states suffer from this kind of constraints).Furthermore,two superior structures favorable in binding are found to be allowed to be possessed by 4^(+) states.These findings would lead to the appearance of two adjacent 4^(+) states,as a common feature,in the low-lying spectra of 4 boson systems.