Phenomenological study on the (p)over-barN → (N)over-barNππ reactions

We extend our recent phenomenological study of pN -> NN pi pi reactions to the (p) over barN -> (N) over barN pi pi reactions for anti-proton beam momenta up to 3.0 GeV within an effective Lagrangian approach. The contribution of N*(1440) with its N sigma decay mode is found to be dominant at the energies close to threshold for (N) over barN pi(+)pi(-) and (N) over barN pi(0)pi(0) channels. At higher energies or for p (n) over bar pi(-)pi(-) and (N) over barN pi(+/-)pi(0) channels where N*(1440) -> N sigma mode cannot contribute, large contributions from double-Delta, Delta(1600) -> N*(1440)pi, Delta(1600) -> Delta pi and Delta(1620) -> Delta pi are found. In the near-threshold region, sizeable contributions from Delta -> Delta pi, Delta -> N pi, N -> Delta pi and nucleon pole are also indicated. Although these results are similar to those for pN -> NN pi pi reactions, the antinucleon nucleon collisions are shown to be complementary to the nucleon nucleon collisions and may even have advantages in some aspects. The PANDA/FAIR experiment is suggested to be an excellent place for studying the properties of relevant N* and Delta* resonances. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.