ANALYSIS OF COMPOUND AND QUASICOMPOUND RESONANCES IN A MULTICHANNEL, FINITE-RANK MODEL

Within a multichannel, multirank model of wide applicability, resonances in complex systems are studied. In particular, compound resonances, which are well observed in nuclear systems can be clearly examined as arising from bound states in subsystems of the coupled-channel system. A less well known, and until now little understood, form of resonance is the quasicompound resonance (or structure). These are seen as arising from resonances in subsystems of the multichannel system. The nature of the two types of resonances is contrasted, in their behavior as the strength of coupling increases. Compound resonances arise infinitely narrow, but of fixed height and increase in width, whereas quasicompound structures arise as small ''bumps'' of finite width, and increase in height. After presentation of the general theory, these properties are illustrated in a simple numerical model calculation. © 1995 The American Physical Society.