Determination of N* amplitudes from associated strangeness production in p+p collisions

Abstract We present the first determination of the energy-dependent amplitudes of N ⁎ resonances extracted from their decay in KΛ pairs in p+p → pK + Λ reactions. A combined Partial Wave Analysis of seven data samples with exclusively reconstructed p+p → pK + Λ events measured by the COSY-TOF, DISTO, FOPI and HADES Collaborations in fixed target experiments at kinetic energies between 2.14 to 3.5 GeV is used to determine the amplitude of the resonant and non-resonant contributions into the associated strangeness final state. The contribution of seven N ⁎ resonances with masses between 1650 MeV/c 2 and 1900 MeV/c 2 for an excess energy between 0 and 600 MeV has been considered. The Σ–p cusp and final state interactions for the p–Λ channel are also included as coherent contributions in the PWA. The N ⁎ contribution is found to be dominant with respect to the phase space emission of the pK Λ + final state at all energies demonstrating the important role played by both N ⁎ and interference effects in hadron–hadron collisions.