Speaker
Description
One of the most important topics of nuclear physics is to describe various nuclear phenomena based on the nucleon-nucleon interactions combined with three-nucleon forces (3$N$Fs). 3$N$Fs are key elements to understand various nuclear phenomena, e.g. binding energies of light mass nuclei [1] and the equation of state of nuclear matter [2]. In the last decades, the study of 3$N$Fs effects has been extensively performed in deuteron--proton ($dp$) scattering at intermediate energies ($E/A$ $\gt60$ MeV). Rigorous numerical Faddeev calculations of the 3$N$ scattering by using $NN$ potentials as well as 3$N$Fs models have made it possible to compare the data to the theoretical calculations. Consequently, the first evidence of 3$N$Fs effects has been found in the $dp$ scattering system [3]. As an extension of 3$N$Fs study, it should be interesting to see how 3$N$Fs act in $p$--$^3$He scattering system. In this system, one could study 3$N$Fs effects in 4$N$ scattering. Also one could approach to 3$N$Fs with the channels of the total iso-spin $T=3/2$.
In order to study 3$N$Fs effects in $p$--$^3$He elastic scattering, we performed the measurement of the cross section and the proton analyzing power $A_y$ at 65 MeV with a polarized proton beam at Research Center for Nuclear Physics (RCNP), Osaka University. The gaseous $^3$He target was bombarded by a polarized proton beam, and scattered protons were detected by using the $E-\Delta E$ detectors which consisted of plastic and NaI(Tl) scintillators. Measured angles were $20^{\circ} - 165^{\circ}$ in the laboratory system ($26.9^{\circ} - 170.1^{\circ}$ in the center of mass system). The typical beam polarizations were 50 % throughout the experiment. We also measured the cross section for $pp$ elastic scattering with the same experimental setup in order to estimate the overall systematic uncertainties.
In the conference, we will report on the obtained data combined with the theoretical calculations.
[1] S. C. Pieper ${\it et\ al.}$, Phys. Rev. C ${\bf 64}$, 014001 (2001).
[2] A. Akmal, V. R. Pandharipande, and D. G. Ravenhall, Phys. Rev. C ${\bf 58}$, 1804 (1998).
[3] K. Sekiguchi ${\it et\ al.}$, Phys. Rev. C ${\bf 65}$, 034003 (2002).
