Resolving the Galactic Center Region's Gamma-Ray Emission and Searching for its Neutrino Counterpart with HAWC and IceCube

The Galactic Center (GC) is a prime candidate for petaelectronvolt cosmic-ray acceleration, with gamma-ray emission observed by the High Altitude Water Cherenkov (HAWC) Observatory extending beyond 100 TeV. We present an analysis of the GC using 2860 days of HAWC data, with increased exposure and improved sensitivity relative to previous results. The best-fit gamma-ray emission model includes a point source (HAWC J1745-2857) and a Galactic diffuse emission component. Assuming a hadronic origin, we construct the corresponding neutrino signal template and search for it in 12 years of IceCube muon-track data. No significant neutrino excess is found, and we report the first upper limit on the high-energy neutrino flux associated with the multi-component spatial model of the GC derived from HAWC data. The limit is approximately 12 times the nominal neutrino flux predicted from the HAWC gamma-ray model under a hadronic interpretation, and therefore it does not yet test the optically thin hadronic scenario.