Simulation of Near Horizontal Muons and Muon Bundles for the HAWC Observatory with CORSIKA

TL;DR

This paper presents simulations of nearly-horizontal muons and muon bundles at the HAWC observatory, aiming to improve understanding of muon detection and primary cosmic ray composition using CORSIKA and GEANT4.

Contribution

It introduces an updated GEANT4-based detector response simulation including volcano models to enhance muon detection analysis at HAWC.

Findings

Simulations estimate HAWC's effective area for high zenith angle muons.

Development of a volcano-inclusive detector response model.

Potential to differentiate primary cosmic ray composition using muon data.

Abstract

The HAWC (High Altitude Water Cerenkov) gamma ray observatory observes muons with nearly-horizontal trajectories corresponding to zenith angles greater than $80^{0}$. HAWC is located at an altitude of 4100 meters a.s.l. (70 deg. atmospheric depth of 2400 g/cm$^{2}$) on the extinct volcano, Sierra Negra in Mexico. In this poster, we summarize the CORSIKA and GEANT4 as well as toy-model based simulations performed to determine the effective area of HAWC to muons from high zenith angle cosmic ray primaries. We are developing an updated GEANT4 based detector response simulation that includes a model of the volcanoes that are located near HAWC. These simulations are investigating the capability to use muon multiplicity and rates to differentiate between the primary particle composition (proton or iron) and measure the primary energy.