Dark matter searches by the planned gamma-ray telescope GAMMA-400

• Published in: arXiv.org 2020-11
• Main Authors: Egorov, Andrey E, Topchiev, Nikolay P, Galper, Arkadiy M, Dalkarov, Oleg D, Leonov, Alexey A, Suchkov, Sergey I, Yurkin, Yuriy T
• Format: Article
• Language: English
• Subjects: Cross-sections; Dark matter; Gamma ray telescopes; Gamma rays; Parameter sensitivity; Particle mass; Photons; Pulsars; Sensitivity; Spaceborne telescopes; Telescopes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2005.09032

Our paper reviews the planned space-based gamma-ray telescope GAMMA-400 and evaluates in details its opportunities in the field of dark matter (DM) indirect searches. We estimated GAMMA-400 mean sensitivity to the diphoton DM annihilation cross section in the Galactic center for DM particle masses in the range of 1-500 GeV. We obtained the sensitivity gain at least by 1.2-1.5 times (depending on DM particle mass) with respect to the expected constraints from 12 years of observations by Fermi-LAT for the case of Einasto DM density profile. The joint analysis of the data from both telescopes may yield the gain up to 1.8-2.3 times. Thus the sensitivity reaches the level of annihilation cross section \(\langle \sigma v \rangle_{\gamma\gamma}(m_\chi=100~\mbox{GeV})\approx 10^{-28}\) cm\(^3\)/s. This will allow us to test the hypothesized narrow lines predicted by specific DM models, particularly the recently proposed pseudo-Goldstone boson DM model. We also considered the decaying DM - in this case the joint analysis may yield the sensitivity gain up to 1.1-2.0 times reaching the level of DM lifetime \(\tau_{\gamma\nu}(m_\chi=100~\mbox{GeV}) \approx 2\cdot 10^{29}\) s. We estimated the GAMMA-400 sensitivity to axion-like particle (ALP) parameters by a potential observation of the supernova explosion in the Local Group. This is very sensitive probe of ALPs reaching the level of ALP-photon coupling constant \(g_{a\gamma} \sim 10^{-13}~\mbox{GeV}^{-1}\) for ALP masses \(m_a \lesssim 1\) neV. We also calculated the sensitivity to ALPs by constraining the modulations in the spectra of the Galactic gamma-ray pulsars due to possible ALP-photon conversion. GAMMA-400 is expected to be more sensitive than the CAST helioscope for ALP masses \(m_a \approx (1-10)\) neV reaching \(g_{a\gamma}^{min} \approx 2\cdot 10^{-11}~\mbox{GeV}^{-1}\). Other potentially interesting targets and candidates are briefly considered too.