A generator of forward neutrons for ultra-peripheral collisions: nOOn

The study of photon-induced reactions in collisions of heavy nuclei at RHIC and the LHC has become an important direction of the research program of these facilities in recent years. In particular, the production of vector mesons in ultra-peripheral collisions (UPC) has been intensively studied. Owing to the intense photon fluxes, the two nuclei participating in such processes undergo electromagnetic dissociation producing neutrons at beam rapidities. Here, we introduce the nOOn (pronounced noon) Monte Carlo program, which generates events containing such neutrons. nOOn is a ROOT based program that can be interfaced with existing generators of vector meson production in UPC or with theoretical calculations of such photonuclear processes. nOOn can also be easily integrated with the simulation programs of the experiments at RHIC and the LHC.

近年来，研究在RHIC和LHC重核碰撞中光子引发的反应已成为这些设施研究计划的重要方向。特别是，在超非中心碰撞（UPC）中矢量介子的产生已得到深入探究。由于强烈的光子通量，参与此类过程的两个核在束流速度下经历电磁解离，产生中子。在此，我们引入了nOOn（发音为noon）蒙特卡洛程序，该程序可生成包含此类中子的事件。nOOn是一个基于ROOT的程序，能够与现有的UPC矢量介子产生生成器或此类光核过程的理论研究相接口。nOOn还可以轻松地与RHIC和LHC实验的模拟程序集成。