Spin-dependentp̄dcross sections at low and intermediate energies

Abstract

Antiproton-deuteron (pd) scattering is calculated at beam energies below 300 MeV within the Glauber approach, utilizing the amplitudes of the JülichN N models. A good agreement is obtained with available experimental data on upolarized differential and integrated pd cross sections. Predictions for polarized totalpd cross sections are presented, obtained within the single scattering approximation including Coulomb-nuclear interference effects. It is found that the total longitudinal and transversalpd cross sections are comparable in absolute value to those forpp scattering. The kinetics of polarization buildup is considered.

Antiproton scattering off3He and4He nuclei at low and intermediate energies

“…The magnitudes of P || and P ⊥ in the region of the beam energy 0-300 MeV are in the order of 5% . In the case of P || they tend to be smaller than those predicted forpp [20,21] andpd [21,22], whereas for P ⊥ they are comparable to the ones for those other antiproton reactions.…”

“…Corresponding investigations for antiproton scattering on a polarized deuteron target were presented in Refs. [19,21,22]. As was shown in Refs.…”

“…Since the polarization degree forpn was found to be on the order of 20% [21] one might naively expect that it could be similar for 3 He because, as mentioned above, in the latter the polarization is carried mainly by the neutron. However, the polarization degree is determined by the ratios of the spindependent cross sections σ i = σ h i + σ int unpolarized cross section σ 0 and, in particular, the larger total Coulomb cross section σ C 0 in thep 3 He system.…”

“…In Eqs. (10) and (11) the quantity α(i) (β(i)) corresponds to the eigenvalue of the σ z -operator +1 (−1) for the i th nucleon. For the 3 He spin projection M S = − 1 2 one should interchange α(1) and β(1) in Eqs.…”

“…As was shown in Refs. [9,11] on the basis of the Glauber-Sitenko theory [13,14] with elementary pN amplitudes taken from the Jülich N N models [15][16][17][18], the pd interaction could provide a comparable or even more effective way than the pp interaction to obtain polarized antiprotons. This conjecture can be checked at a planned experiment [19] at the AD (Antiproton Decelerator) facility at CERN.…”