Meson production and velocity matching

A sequential mechanism of meson production in proton–nucleus collisions leads to meson production at beam energies below the nucleon‐nucleon‐meson‐threshold. In a cascade‐like sequence, a light intermediate particle is created in first nucleon nucleon collision. In a second step, this intermediate particle produces a heavier outgoing meson by interacting with a second nucleon of the same target nucleus. If besides the light intermediate particle there is a deuteron produced in the first step, this can fuse with the nucleon N from the second step to form a bound final (3N) baryonic system. If the velocities of the baryons produced in the two steps are matched then their relative energy is close to zero. Then the 3N fusion to one nucleus will be enhanced and the meson produced cross section for a two body channel should show a bump in the excitation function which has nothing to do with a resonance. Results of Monte‐Carlo simulations of this sequential reaction mechanism are shown.