Electroproduction of the d* dibaryon

Abstract

The unpolarized cross section for the electroproduction of the isoscalar $J^{\pi }=3^{+}$ di-delta dibaryon $d^{\ast }$ is calculated for deuteron target using a simple picture of elastic electron-baryon scattering from the $\Delta \Delta {(}^7{D}_1)$ and the $NN{(}^3{S}_1)$ components of the deuteron. The calculated differential cross section at the electron lab energy of 1 GeV has the value of about 0.24 (0.05) nb/sr at the lab angle of 10${}^{\circ }$ (30${}^{\circ }$) for the Bonn B potential when the dibaryon mass is taken to be 2.1 GeV. The cross section decreases rapidly with increasing dibaryon mass. A large calculated width of 40 MeV for $d^{\ast }(\Delta {\Delta }^7{S}_3)$ combined with a small experimental upper bound of 0.08 MeV for the $d^{\ast }$ decay width appears to have excluded any low-mass $d^{\ast }$ model containing a significant admixture of the $\Delta \Delta {(}^7{S}_3)$ configuration.

Comments: 11 journal-style pages, 8 figures