π+pInteractions atTπ=781MeV

Interactions of 781-MeV ${\pi }^{+}$ mesons with protons were investigated using the Brookhaven National Laboratory 14-in. hydrogen bubble chamber. A total of 2305 events was observed. The data were normalized to a total cross section of 22.2 mb, giving partial cross sections $\sigma ({\pi }^{+}p\to {\pi }^{+}p)=9.5\mathrm{}\pm 0.5$ mb, $\sigma ({\pi }^{+}p\to {\pi }^{+}p{\pi }^0)=9.3\mathrm{}\pm 0.5$ mb, $\sigma ({\pi }^{+}p\to {\pi }^{+}{\pi }^{+}n)=2.15\mathrm{}\pm 0.17$ mb, and a multiple-pion-production cross section of 1.15±0.17 mb. The elastic angular distribution was obtained and is $\frac{d\sigma }{d\omega }=(0.25\mathrm{}\pm 0.03)+(0.90\pm 0.11)cos{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}+(2.57\mathrm{}\pm 0.24){cos}^2{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}+(0.19\mathrm{}\pm 0.22){cos}^3{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}-(1.73\mathrm{}\pm 0.34)cos_{}^4{}_{\mathrm{c}.\mathrm{m}.\mathrm{}}{}^{}$. The kinetic-energy and angular distributions of the outgoing particles in single-pion production are given. The data are compared with other experiments in this energy region and their relevance to the shoulder in the ${\pi }^{+}p$ total cross section near 830 MeV is discussed.