Electromagnetic dissociation of relativistic Si28

We have studied in detail the electromagnetic dissociation of Si28 projectiles at 14.6 GeV/(c nucleon), interacting with Pb, Sn, Cu, and Al targets. Exclusive cross sections were measured for several decay channels, including final states involving the emission of protons, neutrons, and α particles. Excitation energy distributions for the 1n+27Si and 2p+26Mg decay channels were reconstructed with a resolution of 2 MeV, using a constrained kinematic fit. The energy distributions obtained for 1n+27Si are in good agreement with the σ(γ,n) photoneutron cross sections multiplied by the virtual photon spectrum obtained in the Weizsäcker-Williams approximation. A search for the double photon excitation process, based on the dependence of the cross sections on the target atomic number, was performed.