Revisiting the high-spin states in $^{54}$Mn reveals its new structure
Résumé
54Mn (Z=25,N=29) is an odd-odd nucleus with proton and neutron numbers around the magic gap 28. It has 3 proton holes and 1 neutron particle (3h-1p) configuration with respect to the 56Ni magic core. The unpaired proton lies in the 1f7/2 where as unpaired neutron lies in the 2p3/2 orbitals, which are situated just below and above the shell closures at Z, N = 28. The study of the odd-odd nuclei can help us to understand the residual interaction between proton and neutron. The low lying states in 54Mn are primarily single particle in nature which was reproduced by shell model calculations using OXBASH code up to the spin of 9+ [1] . But the higher angular momentum states could not be explained by the same calculations. On the other hand, some of the odd-odd nuclei in this region are known to posses collective deformation at higher spins as in the case of the 1p-1h nucleus 56Co [2]. Therefore, it is interesting to revisit the excited states in 54Mn to understand its higher spin states. The complexity in their structure may come due to the different coupling possibility between the two unpaired nucleons. It is worth mentioning that there are efforts to employ this isotope ( 54Mn) as a cosmic ray chronometer [3].