The shears mechanism

The experimental properties of shears bands are reviewed. The most puzzling characteristic of these structures is the emergence of rotational-like beh avior while the nucleus retains a small quadrupole deformation. Regardless of the details of particular theoretical models, it can be shown that the m ost important degree of freedom in describing the shears mechanism is the s hears angle. It is then possible to develop a semi-classical description of the shears mechanism in which the nature (multipole order) of the interact ion between valence protons and neutrons constituting the shears 'blades' m ay be derived and the dynamics of the system described.