Pionic disintegration of the deuteron

Pionic disintegration of the deuteron between threshold and the 3,3 resonance region is described by a model containing one- and two-body absorption. The two-body absorption mechanism is due to pion and ?-meson rescattering calculated from phenomenological Lagrangians. The role of the ?-meson is crucial in reducing the cross section due to pion exchange. The role of the mass distribution of the ρ-meson, hadronic form factors and final state interactions are investigated. Good agreement with empirical results for the total cross section is obtained with a set of currently accepted values for the meson-nucleon coupling constants and the ρ-mass distribution.     

Bound states of heavy flavor hyperons

Several realistic phenomenological nucleon–nucleon interaction models are employed to investigate the possibility of bound deuteron-like states of such heavy flavor hyperons and nucleons, for which the interaction between the light flavor quark components is expected to be the most significant interaction. The results indicate that deuteron-like bound states are likely to form between nucleons and the and Ξ_cc charm hyperons as well as between Ξ hyperons and double-charm hyperons. Bound states between two Σ_c hyperons are also likely. In the case of beauty hyperons the corresponding states are likely to be deeply bound.     

Pion exchange currents in elastic electron deuteron scattering

The effects of pion-exchange pari and recoil currents on the electromagnetic form factors of the deuteron are calculated. Both exchange currents give significant contributions to the charge form factor and, despite some cancellation, their net effect is appreciable for q² ? 10 fm^?2.     

Pole terms and absorption in theP-wave pion-deuteron interaction

We estimate the accuracy of the conventional ansatz of approximating the lowest order absorptiveP-wave pion-deuteron interactions by pole term amplitudes. By comparing the matrix elements of the approximate pole term and complete absorptive reaction amplitudes for elasticπd scattering we find the pole term approximation to lead to better than 10% accuracy for both theP ₁₁ andP ₃₃ state interactions.     

The reactive two-body part of the pion-nucleus optical potential

We calculate the reactive component of the two-body contribution to the pion-nucleus optical potential from a two-nucleon pion absorption mechanism that predicts the total cross section and angular distributions for π⁺d → pp very well. At threshold the calculated absorptive parts explain most of the values obtained from pionic atom level widths, whereas the dispersive parts, which are very sensitive to wave function correlations are considerably more attractive than what the conventional phenomenological parameters would suggest.     

The absorptive P-wave pion-nucleus optical potential

We derive the absorptive part of the P-wave pion-nucleus optical potential from a two-body model for the absorption mechanism which involves rescattering of a pion and ?-meson through a Δ₃₃ resonant state. The model gives an adequate explanation for the fundamental π⁺d → pp reaction cross section and leads to values for the optical potential parameter which are in fair agreement with those obtained from pionic atom level widths.     

Synthesis of R-(-)-imperanene from the natural lignan hydroxymatairesinol

A convenient and high yielding method for the synthesis of R-(-)-imperanene, starting from the readily available natural lignan hydroxymatairesinol from Norway spruce, was developed. Hydroxymatairesinol was degraded in strongly basic aqueous conditions to (E)-4-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-3-methoxyphenylmethyl)but-3-enoic acid, which was esterified and then reduced by LiAlH(4) to afford R-(-)-imperanene. The configuration at the crucial stereocenter was preserved in the synthesis, and the obtained product was identified by optical rotation measurements and chiral HPLC analyses as the R-(-)-enantiomer (ee 86-92%).