Observation of an Anomalous Structure in Proton Polarization from Deuteron Photodisintegration

Proton polarization in $\ensuremath{\gamma}d\ensuremath{\rightarrow}\mathrm{pn}$ has been measured at c.m. angle around 90\ifmmode^\circ\else\textdegree\fi{} and photon energies from 325 to 725 MeV. The polarization increases sharply with the photon energy, reaching a high maximum of (-80\ifmmode\pm\else\textpm\fi{}8)% around 500-550 MeV. Such a high polarization with a sharp energy dependence seems to indicate a new effect in the dibaryon system.