Double pi(0) Photoproduction on the Proton at GRAAL

Phys Rev Lett. 2003 Jun 6;90(22):222001. doi: 10.1103/PhysRevLett.90.222001. Epub 2003 Jun 3.

Abstract

The double pi(0) photoproduction off the proton has been measured in the beam energy range of 0.65-1.5 GeV. The total and differential cross sections and the Sigma beam asymmetry were extracted. The total cross section measured for the first time in the third resonance region of the nucleon shows a prominent peak. The interpretation of these results by two independent theoretical models infers mostly the selective excitation of P11- and D13-nucleon resonances.