Proton total cross sections on 1H, 2H, 4He, 9Be,C and O in the energy range 180 to 560 MeV

Proton total cross sections have been measured for the nuclei ¹H, ²H, ⁴He, ⁹Be, C and O from 180 to 560 MeV (610 to 1170 MeV/c). The standard transmission technique was used with a resulting total error of 1 % to 2 %. Statistical errors were small (< 1 %) and the major contribution to the final error comes from uncertainties in applying the correction for Coulomb-nuclear interference in elastic scattering at small angles. For ⁴He, ⁹Be, ¹²C. and ¹⁶O this experiment also gives new information on the real part of the spin-independent forward scattering amplitude for proton-nucleus elastic scattering. Total cross sections have been calculated using a Glauber model approach and poor agreement with the data is obtained, even for deuterium.     

A measurement of the branching ratio for the∑ + →pγ decay

We have measured the weak radiative decay branching ratio (∑ ⁺ →pγ)/(∑ ⁺ →pπ⁰). The experiment was carried out at Brookhaven National Laboratory using a low-energy separatedK ^? beam stopping in liquid hydrogen. The∑ ⁺ was tagged by observing the pion fromK ^? K ⁺ p→∑ ⁺π^? in a range telescope, and the gamma was detected in a segmented NaI detector. The result is (2.81±0.39 _?0.43 ^+0.21 )×10^?3, which is consistent with previous measurements. This corresponds to a branching ratio for (∑ ⁺ →pγ)/(∑ ⁺ → all) of (1.45±0.20 _?0.22 ^+0.11 )×10^?3, where the quoted errors are statistical and systematic, respectively. A total of 408 signal events were observed, doubling the previous world total.     

The study of hypernuclei via the (K−, π0) reaction

A significant improvement in the resolution of hypernuclear levels could be attained by studying the (K^–, ⁰) reaction at rest. The new LAMPF neutral meson spectrometer can attain a ⁰ energy resolution of 200 keV. It is shown that, even today, an experiment is feasible and would shed significant light on our understanding of hypernuclei.