Mutual Heavy Ion Dissociation in Peripheral Collisions at Ultrarelativistic Energies

We study mutual dissociation of heavy nuclei in peripheral collisions at ultrarelativistic energies. Earlier this process was proposed for beam luminosity monitoring via simultaneous registration of forward and backward neutrons in zero degree calorimeters at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Electromagnetic dissociation of heavy ions is considered in the framework of the Weizsäcker-Williams method and simulated by the RELDIS code. Photoneutron cross sections measured in different experiments and calculated by the GNASH code are used as input for the calculations of dissociation cross sections. The difference in results obtained with different inputs provides a realistic estimation for the systematic uncertainty of the luminosity monitoring method. Contributions to simultaneous neutron emission due to grazing nuclear interactions is calculated within the abrasion model. A good description of the CERN SPS experimental data on Au and Pb dissociation gives confidence in the predictive power of the model for AuAu and PbPb collisions at the RHIC and the Large Hadron Collider at CERN.