Proton-$\rm ^3He$ elastic scattering at intermediate energies

TL;DR

This study measures various observables in proton-Helium-3 elastic scattering at 65 MeV and compares them with advanced theoretical models, revealing discrepancies that highlight the complexity of nuclear interactions.

Contribution

It provides precise experimental data at intermediate energies and evaluates the effectiveness of four-nucleon scattering calculations with realistic potentials and $ m riangle$-isobar models.

Findings

Discrepancies between measurements and theoretical predictions around the cross section minimum.

Limited success of scaling relations based on $ m ^3He$ binding energy in reproducing data.

High sensitivity of results to nucleon-nucleon potentials and small $ riangle$-isobar effects.

Abstract

We present a precise measurement of the cross section, proton and $\rm ^3He$ analyzing powers, and spin correlation coefficient $C_{y,y}$ for $p$-$\rm ^3He$ elastic scattering near 65 MeV, and a comparison with rigorous four-nucleon scattering calculations based on realistic nuclear potentials and a model with $\Delta$-isobar excitation. Clear discrepancies are seen in some of the measured observables in the regime around the cross section minimum. Theoretical predictions using scaling relations between the calculated cross section and the $\rm ^3 He$ binding energy are not successful in reproducing the data. Large sensitivity to the $NN$ potentials and rather small $\Delta$-isobar effects in the calculated cross section are noticed as different features from those in the deuteron-proton elastic scattering. The results obtained above indicate that $p$-$\rm ^3He$ scattering at intermediate energies is an excellent tool to explore nuclear interactions not accessible by three-nucleon scattering.