Energy peak: Back to the Galactic Center GeV gamma-ray excess

摘要: Abstract We propose a novel mechanism enabling us to have continuum bump as signature of gamma-ray excess in indirect detection experiments dark matter (DM), postulating generic sector having (at least) two DM candidates. With the assumption non-zero mass gap between candidates, heavier one directly communicates partner lighter one. Such then decays into particle along with an “axion-like” (ALP) or “pion”, which subsequently pair photons, via more-than-one step cascade decay process. Since is initiated by obtaining non-trivial fixed boost factor, γ -ray energy spectrum naturally arises even decaying photons. apply main idea GeV -rays from around Galactic Center (GC), and find that relevant observational data well-reproduced theory expectation predicted proposed mechanism. Remarkably, has robust peak at half ALP pion, opposed popular models annihilating Standard Model particles where physical interpretations are not manifest. Our analysis reports substantially improved fits, compared those models, ∼ 900 MeV pion.