Measurement of the all-particle energy spectrum up to the PeV region with the DAMPE experiment

The DArk Matter Particle Explorer (DAMPE), a space-borne detector launched in December 2015, aims to measure the cosmic positron-electron spectrum, conduct high-energy gamma-ray astronomy, and study the flux and composition of cosmic ray protons and nuclei from tens of GeV to the PeV region. This work reports a direct measurement of the all-particle cosmic ray energy spectrum using DAMPE data collected since January 2016. A dedicated analysis framework employs less stringent event selection criteria than those used for individual species spectra, avoiding charge identification, to enable the integrated study of all particle types together. This strategy reduces systematic uncertainties due to purity/contamination of the sample, while enhancing event statistics and then extending the measurement at higher energies than single-species approaches. The resulting all-particle flux spans from 160 GeV to 1 PeV, with unprecedented precision for space-based observations and substantial overlap with ground-based experiments, unveiling spectral details so far hidden by the large uncertainties of previous measurements.