Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark Matter to Account for the PAMELA and ATIC results

TL;DR

This work addresses whether dark matter annihilation or decay can account for PAMELA and ATIC observations by predicting high-energy neutrino signals from charged-lepton decays, specifically $\mu$ and $\tau$, and evaluating detection prospects in neutrino telescopes. It formulates the neutrino flux using $\phi^{A}(E,\theta)$ and $\phi^{D}(E,\theta)$ with line-of-sight $J$-factors $J^{A}$ and $J^{D}$ under an $NFW$ profile, and derives the expected muon rates at Antares and IceCube considering detector response, muon propagation, and backgrounds. The results indicate that annihilating DM with a boost factor and decaying DM with lifetime $\sim 10^{26}$ s can produce detectable high-energy neutrino fluxes from the Galactic center and from DM subhalos, with stronger prospects for annihilation due to the $\rho^2$ density dependence and potential Sommerfeld enhancement. These neutrino observations could help distinguish DM scenarios and constrain DM distribution profiles, offering a complementary probe to gamma rays and charged cosmic rays in unraveling the nature of dark matter.

Abstract

Recent PAMELA data show that positron fraction has an excess above several GeV while anti-proton one is not. Moreover ATIC data indicates that electron/positron flux have a bump from 300 GeV to 800 GeV. Both annihilating dark matter (DM) with large boost factor and decaying DM with the life around $ 10^{26} s$ can account for the PAMELA and ATIC observations if their main final products are charged leptons ($e$, $μ$ and $τ$). In this work, we calculated the neutrino flux arising from $μ$ and $τ$ which originate from annihilating/decaying DM, and estimated the final muon rate in the neutrino telescopes, namely Antares and IceCube. Given the excellent angular resolution, Antares and IceCube are promising to discover the neutrino signals from Galactic center and/or large DM subhalo in annihilating DM scenario, but very challenging in decaying DM scenario.

Figures (7)

• Figure 1: $J_{\Delta \Omega }$ for annihilating and decaying DM as the function of half-angle $\theta$ for the cone centered at the direction of the GC. The DM distribution adopted here is NFW profile.
• Figure 2: The positron fraction from pure muon and tau decays, as well as the positron/electron energy spectrum for annihilating and decaying DM to account for PAMELA and ATIC data. In the figures, the labels on the left, e.g. 0.8 TeV, are the energy of the muon or tau leptons, while the labels on the right, e.g. 860 or 0.85, are the boost factor or life in unit of $10^{26} s$ for annihilating DM and decaying DM respectively.
• Figure 3: The muon and anti-muon neutrino flux for annihilating and decaying DM at the GC. The atmospheric neutrino flux data is from Ref. Honda:2006qj. The x-axis is the energy of neutrinos and the half angle $\theta$ is $10^ \circ$ and $2^ \circ$ respectively. Other labels in the figure are similar with Fig. \ref{['PAM-ATIC']}.
• Figure 4: The total muon and anti-muon rates for annihilating DM in the massive subhalo for the IceCube. The half angle $\theta$ is taken to be $1^ \circ$.
• Figure 5: The scale radius $r_s$ as a function of subhalo mass $M_{v}$.