Roper excitation in ⃗p + α → ⃗p + α + X reactions

We calculate differential cross sections and the spin transfer coefficient D nn in the p+α → p+α+π 0 reaction for proton bombarding energies from 1 to 10 GeV and π 0 − p invariant masses spanning the region of the N * (1440) Roper resonance. Two processes – ∆ excitation in the α-particle and Roper excitation in the proton – are included in an effective reaction model which was shown previously to reproduce existing inclusive spectra. The present calculations demonstrate that these two contributions can be clearly distinguished via D nn , even under kinematic conditions where cross sections alone exhibit no clear peak structure due to the excitation of the Roper.