Recently Zwarts et al. presented data on the forward-backward asymmetry in the particle decay of giant resonances which they interpret as being due to interference with direct knockout processes. In discussing the interference problem we show that the presented features of an asymmetry beginning at the effective particle threshold and increasing with excitation energy are not characteristic for this interference but are expected to arise even in the absence of any resonance decay.

NUCLEAR REACTIONS ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}(\alpha , {\alpha }^{\prime }{\alpha }_0)$, $E_{\alpha }=155\mathrm{}$ MeV; measured $\alpha -{\alpha }_0$ angular correlations; deduced giant resonance decay. Interference of sequential decay and knockout processes.

• Received 2 August 1982

DOI:https://doi.org/10.1103/PhysRevC.27.2422