Nucleon-antinucleon resonances near threshold: A possible explanation of the S(1930) meson

We suggest a dynamical mechanism (dominance of isoscalar meson exchange) which leads to an interpretation of the S(1930) meson in terms of a doublet of $\text{N}$N resonances with J^πC(I^G)=2^?+(0⁺, 1^?). The presence of a doublet implies constructive interference in the $\text{p}$p → $\text{p}$p elastic channel and destructive interference in the $\text{p}$p → $\text{n}$n channel, in agreement with recent experimental evidence. Possible spin and isospin assignments are suggested for other structures seen in $\text{N}$N cross sections near threshold.     

Calculation of the indirect contribution to the heavy-ion nucleon transfer reaction amplitude

The indirect contribution to the heavy-ion nucleon transfer reaction amplitude has been evaluated using the distorted-wave Born approximation neglecting recoil effects. This contribution is usually ignored. Two different formulations of the indirect interaction were tried. One of these formulations gives a completely negligible contribution to the nucleon transfer reaction amplitude. The other gives a negligible effect for the angular dependence of the differential cross section but nevertheless produces a considerable change in the magnitude of the cross section.