Andrea Parenti

The DArk Matter Particle Explorer (DAMPE) is a spaceborne high-energy particle detector that surveys the γ -ray sky above ∼2 GeV with a peak acceptance of ∼0.2 m ² sr. With the 102 months of data collected by DAMPE, we show that the Fermi bubbles are detected at a significance of ∼26 σ and identify a GeV excess in the direction of the Galactic center at ∼7 σ confidence. Both spectra and morphology are consistent with those observed by the Fermi Large Area Telescope (Fermi-LAT) and the GeV excess component can be interpreted by dark matter annihilation with a mass of ∼50 GeV and a velocity-averaged cross section of ∼10 ⁻²⁶ cm ³ s ⁻¹ for the χ χ → b b ¯ channel. Our results thus provide the first independent detection of these two intriguing diffuse γ -ray sources besides Fermi-LAT.

Nickel, one of the most stable elements alongside iron, is the most abundant heavy element beyond iron in cosmic rays. With DAMPE's excellent charge resolution and broad energy range, a high-precision energy spectrum provides valuable insights into the acceleration sources of heavy nuclei and their propagation through the interstellar medium. In this analysis, we report the direct measurement of cosmic-ray nickel spectrum from 10 GeV/n to 2 TeV/n with nine years of flight data. The nickel spectrum is consistent with a single power law with spectral index -2.60 +/- 0.03 from 40 GeV/n to 1 TeV/n. This work provides an accurate measurement of differential flux of nickel with kinetic energy extending to TeV/n for the first time.

The Dark Matter Particle Explorer (DAMPE) has made significant progress in measuring the fluxes of cosmic rays. These new measurements are pivotal in advancing our understanding of the origins and propagation mechanisms of cosmic rays. The bismuth germanium oxide (BGO) calorimeter plays a crucial role in these measurements, particularly in the precise determination of cosmic ray fluxes. However, for a calorimetric experiment like DAMPE, uncertainties in hadronic models persist as a major barrier in achieving more accurate measurements of fluxes of cosmic ray nuclei. This study centers on the measurement of the inelastic hadronic cross sections of carbon and oxygen nuclei interacting with BGO crystals target over an extensive energy range, spanning from 200 GeV to 10 TeV. For carbon nuclei interacting with the BGO target, the measurements of the cross sections have achieved a total relative uncertainty of less than 10% below 8 TeV for carbon, and below 3 TeV for oxygen. For oxygen nuclei, the same level of precision was attained below 3 TeV. Additionally, we compare the experimental results with Geant4 and FLUKA simulations to validate the accuracy and consistency of these simulation tools. Through comprehensive analysis of the inelastic hadronic interaction cross sections, this research provides validation for the hadronic interaction models used in DAMPE's cosmic-ray flux measurements.

Background and Objective: One of the most delicate events in an older persons life is the entrance to a residential care facility (RCF). For institutionalized individuals, maintaining autonomy and a good physical, mental and social health is crucial, and this can be achieved through a...