Speaker
Description
The studies of antinuclei cosmic rays (CR) are currently of great interest as they represent one of the most promising indirect probes of annihilations or decays of dark matter (DM) candidates and few experiments are looking for traces of antideuterons and antihelium near Earth. However, the antinuclei CR also contain a background contribution from antinuclei produced in CR collisions with interstellar gas. To properly simulate the signal and background contributions one needs antinuclei production, annihilation cross sections, and a state-of-the-art propagation model.
We studied the antihelium-3 CR using the GALPROP propagation model and we calculated the fluxes stemming from DM and from secondary processes. The results are based on the available production cross sections of antihelium-3, while the annihilation cross sections of antihelium-3 are estimated for the first time using a data-driven approach based on the novel measurements of antihelium-3 disappearance probability in the material of the ALICE detector at CERN LHC. To this purpose, the antihelium-3 annihilation on proton and helium-4 targets are obtained using the antihelium-3 cross sections implemented in Geant4, which have been scaled accordingly to the results obtained by ALICE.
We show that in the case of antihelium-3 stemming from DM one loses around half of the antinuclei due to annihilations in collisions with interstellar gas, while in the case of the background antihelium-3 flux, a strong energy-dependence, ranging from 75% at low energies and around 10% at high energies, is observed.
Keywords
DM; antinuclei; antihelium; annihilation; cosmic rays; LHC; particle acceleration; ALICE
| Subcategory | Experimental Results |
|---|---|
| other Collaboration | ALICE |
