Reconstruction of Nearly Horizontal Muons in the HAWC Observatory

A Hough transform algorithm is used to identify muons traversing the HAWC observatory by finding a line in the 3d point cloud of PMT hits (x\textunderscore i,y\textunderscore i, and ct\textunderscore i). The arrival direction of the muon can be estimated from this line. Background Extensive Air Shower (EAS) fragments are identified by the presence of a lateral extension of PMT hits in a plane normal to the muon candidate trajectory. A geometry-based simulation has been developed to improve and estimate arrival direction reconstruction resolution and effective area. HAWC is surrounded by volcanoes that provide a variation of material depths from open sky to over 15 km of rock, thereby providing a means to measure muon flux as a function of material depth. A description of the reconstruction techniques and estimates of detector resolution, backgrounds, and effective area as a function of arrival direction, will be provided.