Dark matter decay to a photon and a neutrino: The double monochromatic smoking gun scenario

Abstract

In the energy range from few TeV to 25 TeV, upper bounds on the dark matter decay rate into high energy monochromatic neutrinos have recently become comparable to those on monochromatic gamma-ray lines. This implies clear possibilities of a future double "smoking-gun" evidence for the dark matter particle, from the observation of both a gamma and a neutrino line at the same energy. In particular, we show that a scenario where both lines are induced from the same dark matter particle decay leads to correlations that can already be tested. We study this "double monochromatic" scenario by considering the complete list of lowest dimensional effective operators that could induce such a decay. Furthermore, we argue that, on top of lines from decays into twobody final states, three-body final states can also be highly relevant. In addition to producing a distinct hard photon spectrum, three-body final states also produce a line-like feature in the neutrino spectrum that can be searched for by neutrino telescopes. * Electronic address: celaisat@ulb.ac.be;

Neutrino lines from majoron dark matter

“…Owing to its tree-level coupling, the key feature of majoron DM is arguably its twobody decay into monochromatic neutrinos, a topic that has received a lot of attention in recent years in its own right [21][22][23][24][25]. In fact, since neutrinos are the least-detectable SM particles, any limit on their flux automatically provides a model-independent lower bound on the DM lifetime [26].…”

Cosmological bounds on dark matter-photon coupling

“…Searches for DM decay have been intensively investigated from IceCube telescope data [4]. The DM decay into photons (and into photon and neutrino) has been considered and constrained from cosmic ray emission in [5][6][7]. Also, the possibility of late-time DM decay has been studied in the context of the problems related to the structure formation in the Universe at small scales [8,9].…”

Gamma-ray lines may reveal the CP nature of the dark matter particle

“…For definiteness, we will consider a dark matter particle, ϕ, that has spin zero and is a singlet under the SM gauge group and assume that the detected dark matter signal features some prominent γ-ray lines. γ-ray lines have received a lot of attention in indirect detection analyses [25][26][27][28] because, being essentially free of astrophysical backgrounds, they provide a smoking-gun signature of dark matter. The most general effective Lagrangian that can induce the decay of ϕ into γ-ray lines is with U (1) Y and SU (2), respectively, andB µν and W I µν their corresponding dual tensors.…”