New Test of Nucleon-Nucleon Potential Models

Abstract

We present new measurements of the analyzing power for np scattering at 10.03 MeV accurate to ± 1 x 10 ~3. A new source of systematic error, related to resonances in n-l2 C scattering in the neutron detectors, is discussed. The interaction of the neutron magnetic moment with the Coulomb field of the proton is found to make a significant contribution to the analyzing power at the present level of accuracy. The results are compared to predictions of nucleon-nucleon potential models. New, improved values are reported for the p-and t/-wave spin-orbit phase-shift splittings.

Pion-nucleon coupling constant

“…There are other experiments that are much more constraining for the coupling constant. Here we mention the 12 analyzing-power data at 10.03 MeV taken by Holslin et al [30], the 16 spin correlations measured by Bandyopadhyay et al [31] at 220 MeV, and the 19 spin correlations taken by the same group at 325 MeV. Again, these statements apply to an analysis of the groups within multienergy partial-wave analyses of the complete database, and do not follow from studies of the individual experiments.…”

Corrections for the polarization-dependent efficiency and new neutron-proton analyzing power data at 7.6 MeV

“…3. Again, the crosses use the original PDE corrections [2], and the open circles use the PDE corrections of the present paper. As expected, the changes caused by the new PDE correction are quite small.…”

“…[2,12]. These references analyzed the n-p A y (θ ) data by sorting two-dimensional (2D) spectra [time of flight (TOF) vs CDPH].…”

“…[5] and the new 7.6-MeV data presented here. To achieve [2]. The crosses use the PDE corrections of Ref.…”

“…[8]), they switched to 1.3-cm side detectors to collect their final data (as reported in Ref. [2]). The use of narrow detectors reduced the variation of neutron energy at the side detectors, and, therefore, the variation in 12 C( n,n) A y (θ ).…”