Eur. Phys. J. A (2004) 19: 71-76
https://doi.org/10.1140/epjad/s2004-03-012-2

Hadronic resonances

Baryon resonance analysis from two pion electroproduction at Jefferson Laboratory

INFN, Sezione di Genova, Via Dodecaneso 33, I-16146, Genova, Italy

Received: 31 July 2003
Published online: 12 February 2004

Abstract

The cross section for the reaction e p → e ^′ p π ⁺ π ^- was measured in the resonance region for 1.4<W<2.1 GeV and 0.5<Q ²<1.5 GeV²/c² 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 Δ states shows an evident discrepancy. A better description of the data is obtained either by a sizeable change of the properties of the P ₁₃(1720) resonance or by introducing a new baryon state, not reported in published analyses.