Study of the f0(1500)/f2(1565) production in the exclusive annihilation anti-n p --> pi+ pi+ pi- in flight

Bertin, A.; Bruschi, M.; Capponi, M.; Collamati, A.; De Castro, S.; Dona`, R.; Ferretti, A.; Galli, D.; Giacobbe, B.; Marconi, U.; Piccinini, M.; Poli, M.; Semprini Cesari, * N.; Spighi, R.; Vecchi, S.; Vezzani, A.; Vigotti, F.; Villa, M.; Vitale, A.; Zoccoli, A.; Corradini, M.; Donzella, A.; Lodi Rizzini, E.; Venturelli, L.; Zenoni, A.; Cicalo`, C.; Masoni, A.; Puddu, G.; Serci, S.; Temnikov, P.; Usai, G.; Gortchakov, O. E.; Prakhov, S. N.; Rozhdestvensky, A. M.; Sapozhnikov, M. G.; Tretyak, V. I.; Gianotti, P.; Guaraldo, C.; Lanaro, A.; Lucherini, V.; Nichitiu, F.; Petrascu, C.; Rosca, A.; Ableev, V.; Cavion, C.; Gastaldi, U.; Lombardi, M.; Maron, G.; Vannucci, L.; Vedovato, G.; Bendiscioli, G.; Filippini, V.; Fontana, A.; Montagna, P.; Rotondi, A.; Saino, A.; Salvini, P.; Scoglio, C.; Balestra, Ferruccio; Bergo, D.; Botta, Elena; Bressani, Tullio; Bussa, M. P.; Busso, Luigi; Calvo, D.; Cerello, P.; Costa, Sergio; Damiani, P.; Denisov, O. Y.; D’Isep, § F.; Fanara, C.; Fava, L.; Feliciello, A.; Ferrero, Livio; Filippi, A.; Garfagnini, Raffaello; Grasso, Antonino; Maggiora, A.; Marcello, Simonetta; Mirfakhrai, N.; Panzieri, D.; Rossetto, E.; Tosello, F.; Valacca, L.; Agnello, M.; Iazzi, F.; Minetti, B.; Pauli, G.; Tessaro, S.; Santi, L.

doi:10.1103/PhysRevD.57.55

The spin-parity analysis of the n̄p⃗π+π+π- exclusive reaction in flight is presented. The main aim is to study the (π+π-) invariant mass spectrum in the region around 1500 MeV. The analysis was performed with a Breit-Wigner parametrization for all the resonant states and, for the scalar sector in the mass region below 1.2 GeV, by means of a K-matrix-like treatment. It clearly shows the need for two states, a scalar one (0++) with mass and width (1522±25) MeV and (108±33) MeV, and a tensorial one (2++) with mass (1575±18) MeV and width (119±24) MeV, respectively. In addition, the analysis requires the presence of a scalar state at (1280±55) MeV, (323±13) MeV broad, and of a second vectorial one, in addition to the ρ0(770) signal, with mass and width (1348±33) MeV and (275±10) MeV, respectively.