ИСТИНА

The preparation of an intense beam of polarized antiprotons is the crucial point for the physics program proposed by the PAX collaboration [1] at the future FAIR facility in Darmstadt. A possibility to overcome this experimental challenge is seen in scattering of antiprotons off a polarized $^1$H target in rings [2]. Another possibility is to use the interaction of antiprotons with a polarized deuterium or $^3$He targets. In addition to the issue of the polarization buildup for antiprotons, $\bar p d$ and $\bar p\, ^3$He scattering are interesting for exploring the spin dependence of the elementary $\bar p N$ amplitudes. Spin-dependent total ${\bar p}d$ cross sections for beam energies of 20-300 MeV were already considered by us in [3] using the optical theorem. For this aim the full spin dependence of the forward amplitude of ${\bar p}d$ scattering was derived. Actual calculations of ${\bar p}d$ observables were performed in the context of the Glauber theory in the single-scattering approximation [3], based on elementary amplitudes of $\bar p p$ and $\bar p n$ elastic scattering generated from the $\bar N N$ interaction model developed by the J\"ulich Group [4]. In this contribution we present results for ${\bar p}d$ scattering where also double-scattering effects are taken into account [5]. Besides the spin-dependent cross sections, vector and tensor analyzing powers are calculated using, in part, the formalism developed for $pd$ elastic scattering in Ref. [6]. In addition to the $\bar N N$ amplitudes predicted by the J\"ulich model, we utilize $\bar N N$ amplitudes from a recent partial-wave analysis of $\bar p p$ data [7]. The reliability of the Glauber approximation is examined and it is found that this scheme works very well for $\bar p d$ scattering, even at rather low beam energies such as $\sim 50 $ MeV. It turned out that the unpolarized cross sections are insensitive to the employed $\bar NN$ amplitudes. On the other hand, and as expected, the predictions for polarized ${\bar p}d$ cross sections vary considerably when using different $\bar N N$ amplitudes as input. [1.] V.~Barone et al., [PAX Collaboration], arXiv:hep-ex/0505054. [2.] F. Rathmann et al., Phys.\ Rev.\ Lett. {\bf 94}, 014801 (2005). [3.] Yu.N. Uzikov and J.Haidenbauer, Phys. Rev. C {\bf 79}, 024617 (2009). [4.] T.~Hippchen, J.~Haidenbauer, K.~Holinde, V.~Mull, Phys. Rev. C {\bf 44}, 1323 (1991). [5.] Yu.N. Uzikov, J. Haidenbauer, arXiv:1212.1640 [nucl-th] [6.] M.N. Platonova, V.I. Kukulin, Phys. Rev. C {\bf 81}, 014004 (2010). [7.] D. Zhou, R.G.E. Timmermans, Phys. Rev. C {\bf 86}, 044003 (2012). \end{description}}