Modified hadronic interactions in three-dimensional simulations

We present a method to test the impact of ad hoc modifications of some of the generic parameters of hadronic interactions—cross section, elasticity, and multiplicity—on any observable quantity using full three-dimensional simulations of extensive air showers induced by ultrahigh-energy cosmic rays. Our approach not only extends the existing one-dimensional tools to three dimensions, but also introduces more flexible features to better respond to the needs of both theory and experiment. We first thoroughly validate the conex 3d framework for the simulation of both longitudinal and lateral features of air showers, in particular, for a nonstandard configuration of the framework in which different energy thresholds for modifications are applied. Moreover, we show that the implementations of the ad hoc modifications in this configuration are consistent with the previous one-dimensional simulations. Finally, we discuss the importance of studying the interaction modifications in three dimensions and the effects of parallel modifications of multiple parameters.