Superdeformation in the Doubly Magic Nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow><mml:mn>20</mml:mn></mml:mrow><mml:mrow><mml:mn>40</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>a</mml:mi></mml:mrow><mml:mrow><mml:mn>20</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

A rotational band with seven gamma-ray transitions between states with spin 2 Planck's constant and 16 Planck's constant has been observed in the doubly magic, self-conjugate nucleus (40)(20)Ca(20). The measured transition quadrupole moment of 1.80(+0.39)(-0.29)eb indicates a superdeformed shape with a deformation beta(2) = 0.59(+0.11)(-0.07). The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation.