The present white paper is submitted as part of the “Snowmass” process to help inform the
long-term plans of the United States Department of Energy and the National Science …

Astrophysical neutrinos are excellent probes of astroparticle physics and high-energy
physics. With energies far beyond solar, supernovae, atmospheric, and accelerator …

Many instruments for astroparticle physics are primarily geared towards multi-messenger
astrophysics, to study the origin of cosmic rays and to understand high-energy astrophysical …

In this work we present the interpretation of the energy spectrum and mass composition data
as measured by the Pierre Auger Collaboration above 6× 1017 eV. We use an astrophysical …

We demonstrate that supernova remnant (SNR) shocks embedded within massive star
clusters can reproduce both the cosmic-ray proton and all-particle spectra measured in the …

Hadron spectroscopy provides direct physical measurements that shed light on the
nonperturbative behavior of quantum chromodynamics (QCD). In particular, various exotic …

The majority of astrophysical neutrinos have undetermined origins. The IceCube Neutrino
Observatory has observed astrophysical neutrinos but has not yet identified their sources …

We revisit constraints on decaying very heavy dark matter (VHDM) using the latest ultrahigh-
energy cosmic-ray (UHECR; E≳ 10 18 eV) data and ultrahigh-energy (UHE) γ-ray flux upper …

The recent observations of photons with energies of a few 1014 eV from decaying neutral
pions, both from a direction coincident with a giant molecular cloud (HAWC J1825-134 …

We show, for the first time, radio measurements of the depth of shower maximum (X max) of
air showers induced by cosmic rays that are compared to measurements of the established …