Appearance of Novel Sideways Peaking in Light-Fragment Angular Distributions from 28-GeV Proton Irradiation of U and Au

Energy spectra of fragments with $6<~Z<~12$ produced by the interactions of 28-BeV protons with uranium and gold were measured at several angles with a $\left(\frac{\mathrm{dE}}{\mathrm{dX}}\right)-E$ counter telescope. The angular distributions exhibit broad peaks at ∼70° which tend to become more prominent with increasing fragment $Z$. The presence of these peaks may be evidence for the generation of nuclear shock waves.