BEXCO - Room B(103/104/105)
[CRI196] Detection of Near-Horizontal Muons with the HAWC Observatory
The HAWC (High Altitude Water Cherenkov) gamma ray observatory can detect muons with nearly horizontal trajectories. HAWC is located at an altitude of 4100 meters a.s.l. on Sierra Negra in Mexico, and is composed of 300 water tanks, each 7.3 m in diameter and 4.5 m deep, densely packed over a physical area of approximately 22,000 m2. Previous and current experiments have observed high zenith angle (nearly horizontal) muons at or near sea level. HAWC operates as a hodoscope able to observe multi-TeV muons at zenith angles greater than 75 degrees. This is the first experiment to measure near-horizontal muons at high altitude and with large (>10 m) separations for multiple muons. These muons are distinguishable from extensive air showers by observing nearly horizontal particles moving at a speed consistent with the speed of light. The proximity of the Sierra Negra and Pico de Orizaba volcanoes provides a measurement of muons that penetrate rock overburdens of several km water equivalent. We will present the angular distribution and rate at which HAWC observes these muon events.