He4(p,2p

Abstract

The "He(p, 2p) H reaction has been studied at 250, 350, and 500 MeV using coplanar symmetric and asymmetric geometries. The data are presented as energy-sharing spectra, coplanar symmetric angular distributions, and quasifree angular distributions. A comparison with distorted wave impulse approximation calculations indicates reasonable agreement for small recoil momenta (q & 150 MeV jc). For larger recoil momenta, the distorted-wave impulse approximation calculations increasingly underestimate the data.The discrepancies are substantially reduced by inclusion of a spin-orbit term in the optical potential used to generate the distorted waves. Improvements of the single particle wave function for the struck nucleon influence the calculations to a lesser degree. The remaining discrepancies at large recoil momenta may, in part, be ascribed to multiple scattering effects and exchange processes not included in the standard distorted-wave impulse approximation.NUCLEAR REACTIONS He(p, 2p ) H; measured d~/(d Q3d Q~dT3), 250, 350, 500 MeV, energy sharing spectra, coplanar symmetric angular distributions, quasifree angular distributions; comparison with DWIA calculations.

Polarization Transfer inH4e(e→,e′p→Schiavilla1, Benhar2, Kievsky3 et al. 2005Phys. Rev. Lett.5751012View full textAdd to dashboardCite

“…The charge-exchange spin-orbit term is taken to be purely real, with a depth parameter depending logarithmically on T lab , 15:0 ÿ 1:5logT lab MeV in MeV, and with radius and diffuseness having the values 1.2 fm and 0.15 fm, respectively. The isospin-independent and isospin-dependent spin-orbit terms of v opt T are not well constrained by the data, since these consist exclusively of differential cross sections [17,19,20]. However, they significantly affect the induced polarization P y measured in the 4 Heẽ; e 0p 3 H, as will be shown below.…”

“…In view of these considerations, FSI in the p 3 H scattering state are described in the present work via an optical potential [17,18]. Of course, this approximation has limitations as to the energy range where it is expected to be valid; see discussion below.…”

“…n 3 He charge-exchange cross section data at T lab 57 MeV and 156 MeV (see Refs. [17,18] for a listing of their values). The charge-exchange spin-orbit term is taken to be purely real, with a depth parameter depending logarithmically on T lab , 15:0 ÿ 1:5logT lab MeV in MeV, and with radius and diffuseness having the values 1.2 fm and 0.15 fm, respectively.…”

Search for Gamow-Teller strength in the continuum via theHe3(n,p)Celler1, Yen2, Alford3 et al. 1993Phys. Rev. CSelf Cite7010View full textAdd to dashboardCite

“…DWIA Calculations of cross sections for the He(n, p) H reaction were carried out using the code Dwsi [17]. Optical potentials required for the calculations were taken from a study of the He(p, 2p) reaction at intermediate energies [18]. In that work, optical parameters were derived by fitting elastic scattering data for p+ He and p + H at in- [18] also showed no significant change in the shape of the angular distributions, although the zero-degree cross sections for GT transitions varied over a range of about 20% relative to those calculated with the interpolated parameters.…”

A survey of the alpha-nucleon interaction

“…Such microscopic studies have, in fact, been made more or less within the framework of the resonating group method (RGM) of Wheeler (Bransden and McKee, 1954;Hochberg et al, 1954Hochberg et al, ,1955Van der Spuy, 1956;Sugie et al, 1957;Nagata et al, 1959;Lasker et al, 1961;Kanada et al, 1963aKanada et al, , 1963bFranco, 1968;Thompson et al, 1969;Hackenbroich, 1970,1971;Omojola, 1970;Reichstein and Tang, 1970;Thompson and Tang, 1971;Thompson et al, 1972;Chwieroth et al, 1974;Hackenbroich et al, 1974;Thompson et al, 1977).…”