Reactionp+p→π++d

Abstract

Absolute differential cross sections for the reaction $p+p\to {\pi }^{+}+d$ have been measured at incident proton energies (lab system) from 310 to 338 Mev and at meson angles (c.m.) from 30° to 90°. The two final particles were counted in coincidence. The data are well fitted by the phenomenological theoretical expression $4\pi \frac{d\sigma }{d\Omega }(\mathrm{c}.\mathrm{m}.\mathrm{})={\alpha }_{10}\eta +{\beta }_{10}{\eta }^3\frac{(x+{cos}^2\theta )}{x+\frac{1}{3}},$ with $x=0.082\mathrm{}\pm 0.034$, ${\alpha }_{10}=(0.138\mathrm{}\pm 0.015)\times {10}^{-27\mathrm{}}$ ${\mathrm{cm}}^2$, and ${\beta }_{10}=(1.01\mathrm{}\pm 0.08)\times {10}^{-27\mathrm{}}$ ${\mathrm{cm}}^2$; $\theta =\mathrm{meson}$ c.m. angle and $\eta =\frac{p_{\pi } (\mathrm{c}.\mathrm{m}.\mathrm{})}{m_{\pi }c}$. By measuring ${\alpha }_{10}$ we have determined directly the amount of $S$-wave in this reaction.