Measurement ofp+p→π++dat High Momentum Transfers

Abstract

Three measurements of the differential cross section for $p+p\to {\pi }^{+}+d$ have been made at the Brookhaven AGS, at incident laboratory momenta 11.6, 15.0, and 22.9 BeV/c and corresponding deuteron angles 55.7°, 43.4°, and 34.7° in the center-of-mass system. The internal proton beam was made to strike a polyethylene target, and coincidences were taken between the outgoing pion and deuteron by placing counter telescopes both inside and outside the AGS ring. Both particles were momentum analyzed and the deuteron was identified by the use of a gas-filled differential Cerenkov counter. The pion was identified by time of flight. The total number of protons incident on the target was obtained by radiochemical analysis of the ${\mathrm{Be}}^7$ spallation product from carbon. Differential cross sections in the region ${10}^{-35\mathrm{}}$ to ${10}^{-34\mathrm{}}$ ${\mathrm{cm}}^2$/sr in the c.m. system were obtained. Our cross sections are ∼${10}^4$ times smaller than other measurements at lower energies and smaller angles; we conclude that this process decreases rapidly both with increasing energy and with increasing c.m. angle.