First implications of Tibet AS$_γ$ data for heavy dark matter

Abstract

Extensive air shower detectors of gamma rays in the sub-PeV energy region provide a new and relatively unexplored window for dark matter searches. Here we derive some implications of the recently published Tibet ASγ data for decaying dark matter candidates. The available spectral information is already useful in obtaining competitive constraints, surpassing existing limits above 10 PeV mass for hadronic or massive boson final states. This is particularly true if accounting for a benchmark astrophysical background of Galactic cosmic rays in the (0.1-1) PeV range. By relying on the arrival distribution of the photons, we show that significantly better sensitivity can be attained, comparable or better than IceCube also for most leptonic final states. Full data exploitation requires however further information disclosure.

Multi-messenger high-energy signatures of decaying dark matter and the effect of background light

“…2 This results into a significant uncertainty due to the EBL models on the dark matter constraints as shown in figure 7 The lower panels show the ratio between the neutrino HESE limits and the extragalactic gamma-ray limits we obtain (left) and galactic gamma-ray limits (right). Also shown with gray thin lines are previous bounds [35,36,48,52].…”

“…Heavy decaying dark matter also gives rise to gamma-rays [41][42][43] which have been searched with gamma-ray telescopes. Diffuse gamma-ray data places strong constraints on the dark matter lifetime for various decay channels, and these largely disfavor the dark matter hypothesis for IceCube's observations [44][45][46][47][48][49][50][51][52][53][54]. In order to properly constrain the size of the dark matter contribution in HESE, we need to establish the robustness of these gamma-ray bounds.…”

“…Similarly to the extragalactic limit, our Tibet-AS γ constraint excludes background modeling. By contrast, [52] employ a modeling of the background, and their limits correspond to the requirement that the gamma-ray remain below the 1σ upper limits in all three bins energy bins reported by Tibet-As γ . Compared to these limits, our constraint worsens significantly at higher masses, demonstrating the importance of a background treatment.…”

Ultrahigh-energy diffuse gamma-ray emission from cosmic-ray interactions with medium surrounding acceleration sources

“…Some fresh sources in such a region may explain the excess (Bi et al 2009;Guo et al 2016a). Very recently, the DGE in the Galactic plane above 100 TeV energies was for the first time measured by the Tibet-ASγ experiment (Amenomori et al 2021), which has attracted wide attention for possible physical discussion (Kimura et al 2021;Dzhatdoev 2021;Fang & Murase 2021;Liu & Wang 2021;Qiao et al 2021;Huentemeyer 2021;Esmaili & Serpico 2021;Koldobskiy et al 2021;Bouyahiaoui et al 2021;Dzhappuev et al 2021;Li & Ma 2021;Tibaldo et al 2021;Nath Maity et al 2021). The Tibet-ASγ fluxes are higher than the prediction of the conventional CR propagation model, and additional components or modification of the conventional propagation framework may be needed (Amenomori et al 2021;Liu & Wang 2021;Qiao et al 2021).…”

Constraining the position of the knee in the galactic cosmic ray spectrum with ultra-high-energy diffuse $γ$-rays

“…The Galactic diffuse γ-ray emission (DGE) is expected to be produced by interactions between CRs and the interstellar medium (ISM) as well as the interstellar radiation field (ISRF), during the propagation of CRs in the Milky Way. Justly recently, the DGE in the Galactic plane at 957 TeV energies was for the first time measured by the Tibet-ASγ experiment [8], which has attracted wide attention for possible physical discussion [9][10][11][12][13][14][15][16][17][18][19][20][21]. This measurement shed new light to study the individual nuclear spectrum.…”