Direct observation of a rho decay of the D13(1520) baryon resonance

Phys Rev Lett. 2001 Jul 30;87(5):052001. doi: 10.1103/PhysRevLett.87.052001. Epub 2001 Jul 11.

Abstract

The reaction gammap-->pi(+)pi(0)n has been measured at MAMI for photon energies up to 820 MeV. Invariant mass spectra of the particles in the final state (pi(+)n), (pi(0)n), (pi(+)pi(0)) have been determined for several bins of incident photon energy. Differences in pi(+)pi(0) and simultaneously measured pi(0)pi(0) invariant mass distributions are assigned to a rho branch of the D13(1520) nucleon resonance.