The quantity R in a new expression $E_I=A[\sqrt{\mathrm{BI}(I+R)+1\mathrm{}}-1\mathrm{}]$, which is introduced on the basis of the Bohr Hamiltonian and which can describe universally the yrast lines of even-even nuclei over the entire nuclear chart in very high precision, is regarded as a fingerprint to identify the nuclear γ shape as shown by both the theory and the survey of experimental data. This fingerprint shows that some of the observed superdeformed bands have axial asymmetry if the previous spin assignments are valid.

• Received 17 July 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.4132