Measurement of the proton polarization in deuteron photodisintegration at photon energies between 350 and 700 MeV

The proton polarization in the γd → pn reaction has been measured at a c.m. angle of 90° and photon energies between 350 and 700 MeV, using a carbon polarimeter. The magnitude of the polarization shows a sharp energy dependence with a peak of about ?80% at around 500–550 MeV. This feature cannot be explained by conventional models and seems to indicate a new mechanism in the dibaryon system.