Mean-field repulsion of colliding nuclear matter at relativistic energies
The authors study the energy behaviour of two penetrating interacting nuclear matter systems in a relativistic quantum field theory proposed by J.D. Walecka (1974). They show that, compared with non-interacting systems, the relative flow velocity is significantly reduced due to the repulsive omega -meson field and discuss an effective potential between the matter systems.
It was recently suggested that the rise in the photopion cross sections above 500 Mev may be interpreted as being due to another resonance in the pion- nucleon system. Since the pi /sup +/ cross section is the larger, the resonance must presumably be in a T = 1/2 state. From observation of the angular distributions, it is also possible to determine the probable angular momentum and parity of such a state. (W.D.M.)