Measurement of ep-->e' ppi+ pi- and baryon resonance analysis

Phys Rev Lett. 2003 Jul 11;91(2):022002. doi: 10.1103/PhysRevLett.91.022002. Epub 2003 Jul 11.


The cross section for the reaction ep-->e(')ppi(+)pi(-) was measured in the resonance region for 1.4<W<2.1 GeV and 0.5<Q2<1.5 GeV(2)/c(2) using the CLAS detector at Jefferson Laboratory. The data show resonant structures not visible in previous experiments. The comparison of our data to a phenomenological prediction using available information on N(*) and Delta states shows an evident discrepancy. A better description of the data is obtained either by a sizable change of the properties of the P13(1720) resonance or by introducing a new baryon state, not reported in published analyses.