부산대학교 도서관

The differential cross section for the reaction $^{12}$C$(\gamma ,\pi ^{+}p)$ has been measured in the $\Delta$ resonance region at high recoil momenta of the residual nuclear system. The data are analysed under the assumption that the formation of $\pi^+p$ pairs may be interpreted as $\gamma\Delta^{++}\to\pi^+p$ process, proceeding on the $\Delta^{++}$ constituent in a target nucleus. As a result, the estimation $N_\Delta=0.028\pm 0.008$ deltas per nucleon in $^{12}$C was obtained.
Comment: LaTeX, 8 pages, 3 Postscript figures, submitted to Rhys. Lett. B