Measurement ofnpCharge Exchange for Neutron Energies 150-800 MeV

Abstract

The s andw variations of the np charge-exchange (np-*pn) cross section are measured to be relatively smooth and without structure at intermediate energies-in sharp contast to previous results.

Coarse-grained potential analysis of neutron-proton and proton-proton scattering below the pion production threshold

“…Unfortunately there seems to be mutually incompatible data, most likely due to under and overestimations of statistical and systematic uncertainties from the experimental side. A clear example of this inconsistencies, at backward angles in this case, are the two data sets of np diferential cross section at 162 MeV [25,26] plotted in the bottom right panel of Fig. 1 for illustration purposes.…”

Pion-nucleon coupling constant

“…It was suggested by Chew [28] as early as 1958 that this is a good place to extract the pion-nucleon coupling constant. If this is true, then a very important group of data should be the Los Alamos set of backward cross sections measured by Bonner et al [29]. However, we have seen already from Table V that all observables, and not the differential cross sections in particular, favor a low coupling constant.…”

Measurement of the AbsolutenpScattering Differential Cross Section at 194 MeV

“…The present results are in good accord with the PWA, but deviate systematically from other recent measurements. The neutron-proton elastic scattering database at intermediate energies is plagued by experimental inconsistencies and cross section normalization difficulties [1,2,3]. These problems have led the most sophisticated partial wave analyses (PWA) of the data [4,5,6] to ignore the majority (including the most recent) of measured cross sections, while the literature is filled with heated debates over experimental and theoretical methods [7,8], including proposed radical "doctoring" (angledependent renormalization) to "salvage" allegedly flawed data [9].…”