A study of the reaction pi+ + d --> p + p has been performed in the energy range of 18 - 44 MeV. Total cross sections and differential cross sections at six angles have been measured at 15 energies with an energy increment of 1 - 2 MeV. This is the most systematic data set in this energy range. No structure in the energy dependence of the cross section has been observed within the accuracy of this experiment.
Measurements have been made of pi+ absorption on He3 at T_pi+ = 118, 162, and 239 MeV using the Large Acceptance Detector System (LADS). The nearly 4pi solid angle coverage of this detector minimizes uncertainties associated with extrapolations over unmeasured regions of phase space. The total absorption cross section is reported. In addition, the total cross section is divided into components in which only two or all three nucleons play a significant role in the process. These are the first direct measurements of the total and three nucleon absorption cross sections.
ABSORPTION CROSS SECTION.
ABSORPTION CROSS SECTION.
Statistical errors only. Systematic error is estimated as < 8 pct.
We present the first polarization measurements for pion absorption on a nucleus heavier than the deuteron. The polarization of protons resulting from π+ absorption in the He3 was measured at bombarding energies of 120 and 250 MeV. Protons from absorption in a quasideuteron were selected by applying kinematical constraints. A significant discrepancy was observed between the experimental results and theoretical predictions. At 120 MeV the measured polarizations for He3 are consistent with those of the deuteron. At 250 MeV the angular distribution of the polarization is significantly different than for the deuteron, showing sensitivity to the nuclear density, and thus may be sensitive to short range correlations between nucleons.
LEGENDRE POLYNOMIAL COEFFICIENTS. NOTE THE FORM OF THE LEGENDRE EXPANSION DIFFERS BY A FACTOR P**-2 FROM THE CONVENTIONAL ONE.
The total cross section and the differential cross sections of the reactions π + d →π + d (elastic scattering) →π + pn (inelastic scattering) →π 0 pp (charge exchange scattering) →γ pp (radiative absorption) → pp , (non-radiative absorption) have been measured using 85 000 pictures of 290 MeV/ c positive pions in the 38 cm Princeton-Pennsylvania bubble chamber. The elastic, inelastic and charge exchange scattering data are more complete than any previous data in this energy range.
FOUND BY EXTRAPOLATION OF PARTIAL CROSS SECTION TO ZERO SOLID ANGLE.
TOTAL NUMBER EVENTS= 3400.