Elastic pbar-d scattering and total pbar-d cross sections

Elastic pbar-d scattering is studied within the Glauber theory based on the single- and double pbar-N scattering mechanisms. The full spin dependence of the elementary pbar-N scattering amplitudes is taken into account and both the S- and D-wave components of the deuteron are considered. The treatment of the spin dependence is done in a (properly modified) formalism developed recently by Platonova and Kukulin for the pd -> pd scattering process. Predictions for differential cross sections and the spin observables A_y^d, A_y^pbar, A_xx, A_yy are presented for antiproton beam energies between 50 and 300 MeV, using amplitudes generated from the Nbar-N interaction model developed by the Juelich group. Total polarized cross sections are calculated utilizing the optical theorem. The efficiency of the polarization buildup for antiprotons in a storage ring is investigated.Comment: 14 pages, 15 figures; some comments added, figure added, signs of some spin-dependent cross sections correcte

A possibility to determine the P-parity of the Θ+\Theta^+ pentaquark in the pn→Λ0Θ+{p}{n}\to \Lambda^0\Theta^+ reaction

Spin structure of the reaction ${\vec p}{\vec n}\to {\vec \Lambda^0} {\vec \Theta}$ is analysed at the threshold in a model independent way under assumption that the $\Theta^+$ is an isosinglet. We found that the sign of the spin-spin correlation parameter $C_{x,x}$ being measured in a double-spin experiment, determines the P-parity of the $\Theta^+$ unambiguously. Furthermore we show that the polarization coefficients $K_x^x,K_y^y$ and $K_z^z$ which describe the polarization transfer from polarized beam or target to the final $\Lambda^0$ and $\Theta^+$ are nonzero for a positive parity of the $\Theta^+$ and equal zero for a negative parity. It allows one to determine the P-parity of the $\Theta^+$ in a single-spin measurement, since the polarization of the $\Lambda^0$ can be measured via its decay $\Lambda^0\to \pi^-+ p$.Comment: 8 pages, Latex . The spin 3/2 of the $\Theta^+$ and a discrimination for the isospin T=0,1 and 2 are briefly discussed; minor corrections are performe

Deuteron Breakup pd→pnppd\to pnp in Specific Kinematics and Short-Range NN-Interaction

Deuteron breakup processes $p+d\to (NN)_{s,t}+N$ are studied in the kinematics of backward elastic pd-scattering at law relative momenta of the NN-pair $k\sim 0-50 MeV/c$ for initial energies $T_0=0.5-2.5 GeV$ in the framework of the known mechanisms of the $pd\to dp$ process including rescatterings in the initial and final states. A considerable suppression of the $\Delta-$ and $N^*-$ isobar excitation mechanisms is found for the production of the singlet $(NN)_s$-pair. As a result, one nucleon exchange mechanism can be identified in the cross section and polarization observables by the node of the half-off-shell NN$(~^1S_0)$-scattering amplitude, $t(q,k)$, at $q\sim 0.4$ GeV/c