K+Meson Photoproduction from Complex Nuclei

Abstract

${K}^{+}$ meson yields have been measured from various elements using a bremsstrahlung beam of maximum energy of 1150 MeV. The ${K}^{+}$ mesons were detected using a magnetic spectrometer set at a momentum of 415 $\frac{\mathrm{MeV}}{c}$ and laboratory angle of 35\ifmmode^\circ\else\textdegree\fi{}. These kinematical conditions correspond to an angle of 90\ifmmode^\circ\else\textdegree\fi{} in the center of mass and a photon energy of 1054 MeV for the reaction $\ensuremath{\gamma}+p\ensuremath{\rightarrow}{K}^{+}+\ensuremath{\Lambda}$. The targets used were Be, C, Al, Cu, Ag, W, and Pb. The results show a slight decrease in the yield per proton as a function of atomic number. A crude estimate yields a mean free path in nuclear matter of the order of 10 F for the geometry of this experiment.