200 GeV Proton Interactions in Nuclear Emulsion

Abstract

The mean‐free‐path for inelastic interactions of 200 GeV protons in nuclear emulsion has been measured using the techniques of along‐the‐track scanning and area scanning. The results obtained are, respectively, ${\lambda }_{\mathrm{inel}}\text{\hspace{0.17em}=\hspace{0.17em}35.3\hspace{0.17em}±\hspace{0.17em}1.0\hspace{0.17em}}\mathrm{cm}$ and ${\lambda }_{\mathrm{inel}}\text{\hspace{0.17em}=\hspace{0.17em}33.1\hspace{0.17em}±\hspace{0.17em}1.5\hspace{0.17em}}\mathrm{cm}$ . The average charged multiplicities have been found to be $〈{\mathrm{n}}_{\mathrm{s}}\text{〉\hspace{0.17em}=\hspace{0.17em}8.2\hspace{0.17em}±\hspace{0.17em}0.2}$ for ‘white’ stars and $〈{\mathrm{n}}_{\mathrm{s}}\text{〉\hspace{0.17em}=\hspace{0.17em}12.9\hspace{0.17em}±\hspace{0.17em}0.15}$ for all events. A plot of n_s versus N_h (where N_h is the number of black and grey tracks) shows a linear relation over the region $\text{0\hspace{0.17em}≤\hspace{0.17em}}{\mathrm{N}}_{\mathrm{h}}\text{\hspace{0.17em}≤\hspace{0.17em}25}$ . The Castagnoli method applied to ‘white’ stars overestimates the C.M. energy by ∼ 40%, however, for stars with ${\mathrm{N}}_{\mathrm{h}}\text{\hspace{0.17em}≥\hspace{0.17em}1}$ , there is good agreement.