Measurement of the cosmic p+He energy spectrum from 50 GeV to 0.5 PeV with the DAMPE space mission

Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer is a satellite-based cosmic-ray experiment that has been operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 464 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at 600 GeV has been observed, along with a softening at 29 TeV measured with a 6.6σ significance. Moreover, the detector features and the analysis approach allowed for the extension of the spectral measurement up to the sub-PeV region. Even if with small statistical significance due to the low number of events, data suggest a new spectral hardening at about 150 TeV.Received 31 March 2023Revised 27 October 2023Accepted 17 May 2024DOI:https://doi.org/10.1103/PhysRevD.109.L121101© 2024 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCosmic ray accelerationCosmic ray composition & spectraCosmic ray propagationCosmic ray sourcesCosmic rays & astroparticlesGravitation, Cosmology & Astrophysics