The πN→ππN reaction around the N^{*}(1440) energy

We study the pi N ->pi pi N reaction around the N-*(1440) mass-shell energy. Considering the total cross sections and invariant mass distributions, we discuss the role of N-*(1440) and its decay processes on this reaction. The calculation is performed by extending our previous approach [Phys. Rev. C 69, 025206 (2004)], in which only the nucleon and Delta(1232) were considered as intermediate baryon states. The characteristics in the recent data of the pi(-)p ->pi(0)pi(0)n reaction measured by Crystal Ball Collaboration can be understood as a strong interference between the two decay processes: N-*(1440)->pi Delta and N-*(1440)-> N(pi pi)(S wave)(I=0). It is also found that the scalar-isoscalar pi pi rescattering effect in the NN*(pi pi)(S wave)(I=0) vertex, which corresponds to the propagation of sigma meson, seems to be necessary for explaining the several observables of the pi N ->pi pi N reaction: the large asymmetric shape in the pi(0)pi(0) invariant mass distributions of the pi(-)p ->pi(0)pi(0)n reaction and the pi(+)p ->pi(+)pi(+)n total cross section.