Forward differential cross sections for isospin-1 bosons produced in $p+p\to d+x^{+}$ were measured using a deuteron missing-mass spectrometer at a small angle between 4.0- and $12.3-\frac{\mathrm{GeV}}{c}$ incident momentum. Differential cross sections for ${\pi }^{+}$ and ${\rho }^{+}$ were extracted from the spectra using phase-space backgrounds. They range from 10.4 to 0.4 μb/sr for ${\pi }^{+}$ and from 1.4 to 0.3 μb/sr for ${\rho }^{+}$. A bump near 6 $\frac{\mathrm{GeV}}{c}$ appears in both $d\pi$ and $d\rho$ channels. No clear evidence is seen for higher-mass bosons. The possible ${\delta }^{+}$ cross sections average less than 0.01 μb/sr.

• Received 12 November 1970

DOI:https://doi.org/10.1103/PhysRevLett.26.108