Geometric Optimization of the MATHUSLA Detector

MATHUSLA is a proposed displaced vertex detector for neutral long-lived particle decays. It was proposed with general specifications of the size of its decay volume and its location. In this study, different simplified models containing LLPs are investigated using Monte Carlo event generators, and LLP decay probability maps are generated. Specific optimal configurations for the detector are found for each model according to available land around the CMS detector. We demonstrate that the placement and dimensions of a proposed 10000 m2 engineering benchmark can be modified so that an improvement in acceptance (up to 12% more LLP decays) is observed. Also, it is found that the engineering benchmark would observe about 80% of the number of LLP decays that the earlier MATHUSLA200 physics sensitivity benchmark with four times the area would observe.