Simulations of the Angular Kinetic-Energy Distribution of Halo Weakly Interacting Massive Particles for Directional Dark Matter Detection Experiments

Abstract In this paper, as the second step of our study on developing data analysis procedures for using 3-dimensional information offered by directional Dark Matter detection experiments in the future, we investigate the patterns of the angular distribution of the Monte Carlo-generated 3-D kinetic energy of halo Weakly Interacting Massive Particles (WIMPs) in different celestial coordinate systems. We will demonstrate the "directionality" of the angular distributions of the 3-D WIMP kinetic energy by both of their annual and diurnal modulations. For readers' reference, the angular distribution patterns of the 3-D WIMP kinetic energy in the "laboratory (location)-dependent" reference frames of several underground laboratories are given in the Appendix.