We evaluate the helicity dependence of the differential and total cross section for the scattering of longitudinally polarized neutrons on unpolarized neutrons at E = 45 MeV following a SIN experiment and at E = 230 MeV in anticipation of an experiment at TRIUMF. (Both experiments study proton-proton scattering of course, namely p+p→p+p). Calculations are based on the Desplanques, Donoghue and Holstein (DDH) theory for the weak NN interaction and on the Paris potential for the strong NN force. The results can be expressed as a linear combination in the (DDH) weak parameters hρ0, hρ2 and hω0, corresponding to exchanges of isoscalar ρ-, isotensor ρ-, and isoscalar ω- mesons, respectively. For the asymmetry in the total cross section we have found, using DDH suggested "best values", Az (45 MeV) = -2.62 × 10-7 and Az (230 MeV) = 0.07 × 10-7. The small value of Az at 230 MeV is due to a sign change in the differential asymmetry. As for the asymmetry in the differential cross section we notice that even at the lower energy E = 45 MeV, the asymmetry in the differential cross section deviates from isotropy, since J > 0 weak amplitudes cannot be neglected.
ASJC Scopus subject areas
- Nuclear and High Energy Physics