Photoneutron Reactions on Xe Nuclei and Their Electromagnetic Dissociation in Colliders

The electromagnetic dissociation of ultrarelativistic nuclei has a substantial impact on the lifetime of beams in the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC), and secondary nuclei produced upon this dissociation may have an adverse effect on collider components. At the same time, the detection of neutrons originating from the electromagnetic dissociation process makes it possible to monitor the luminosity of colliders. In order to calculate the total and partial cross sections for the electromagnetic dissociation process by the Weizsäcker–Williams method, one needs reliable photonuclear reaction models preliminarily tested via a comparison of the results that they produce with available experimental data. Since the commissioning of the LHC, attention has been given primarily to Pb– Pb collisions. A run involving Xe nuclei was also performed. In contrast to the case of Pb nuclei, for which the photonuclear reaction and electromagnetic dissociation cross sections have been measured at various laboratories, there are no data for Xe. By employing the experimental–theoretical method, the ( ), ( ), ( ), and ( , abs) cross sections for the Xe nucleus are evaluated on the basis of available data for the neighboring nucleus of I and the combined photonuclear reaction model (CPNRM). It is found that the results of CPNRM calculations performed for Xe at photon energies up to 40 MeV by employing the TENDL-2017 library compiled by means of the TALYS code are close to one another and are in fairly good agreement with data obtained at the Saclay laboratory for I. These new evaluated data, the TENDL-2017 library, and approximations of the total photoabsorption cross sections above the pion production threshold are used to calculate the electromagnetic dissociation cross section for Xe at the LHC and at the FCC-hh collider being designed. The results of these calculations are compared with their counterparts obtained on the basis of the RELDIS model.