Fraunhofer diffraction of coherent and incoherent nuclear matter waves by complementary screens

The analogy between Fraunhofer diffraction effects observed in nuclear and subnuclear collisions and those observed with light diffracted by complementary screens is revisited. Emphasis will be put on the collision mechanisms playing a role analogous to that of an aperture in light diffraction. These analogies are illustrated with examples involving coherent and incoherent nuclear matter waves.

Figure 1

Measured interference patterns attributed to Fraunhofer diffraction, by an opaque disk (diamonds), by an aperture: coherent waves (squares), incoherent waves (triangles) in arbitrary units. The full curve is the Airy pattern (see text). In the data the dip behavior between the first and second peaks is much less pronounced than shown on the calculated curve. A detailed calculation including the effect of the nuclear surface diffuseness will damp out the diffraction oscillations.

Figure 2

Two incoherent pointlike sources are located at ${\mathit{r}}_{\mathbf{1}}$ and ${\mathit{r}}_{\mathbf{2}}$. The emitted particles are counted by detectors $\mathit{a}$ and $\mathit{b}$. Both emission sources contribute to both counters. For identical particles, two alternative indistinguishable histories are possible, drawn with a full and a dashed line respectively.