Determination of the magnetic dipole moment of the rho meson using 4 pion electroproduction data

Abstract: We determine the magnetic dipole moment of the rho meson using preliminary data from the BaBar Collaboration for the $e^+ e^- \to \pi^+ \pi^- 2 \pi^0$ process, in the center of mass energy range from 0.9 to 2.2 GeV. We describe the $\gamma^* \to 4\pi$ vertex using a vector meson dominance model, including the intermediate resonance contributions relevant at these energies. We find that $\mu_\rho = 2.1 \pm 0.5$ in $e/2 m_\rho$ units.