A new type of resonance appears to have been discovered in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C${,}^{12}$C($0_2^{+}$)${)}^{12}$C($0_2^{+}$) reaction at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=33 MeV. We suggest that it is formed coherently from nearly degenerate resonances with different l values. Taking the individual resonances to be members of a cluster rotational band with 2n+l=const, the coherence can be shown to follow from Levinson’s theorem. The new kind of resonance does not have a definite angular momentum but corresponds to an approximate shape eigenstate.

• Received 9 November 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.3709