Positrons from dark matter annihilation in the galactic halo: Theoretical uncertainties

Abstract

Indirect detection signals from dark matter annihilation are studied in the positron channel. We discuss in detail the positron propagation inside the galactic medium: we present novel solutions of the diffusion and propagation equations and we focus on the determination of the astrophysical uncertainties which affect the positron dark matter signal. We find dark matter scenarios and propagation models that nicely fit existing data on the positron fraction. Finally, we present predictions both on the positron fraction and on the flux for already running or planned space experiments, concluding that they have the potential to discriminate a possible signal from the background and, in some cases, to distinguish among different astrophysical propagation models. PACS numbers: 95.35.+d,98.35.Gi,11.30.Pb,95.30.Cq

Cosmic ray anomalies from the MSSM?

“…In this respect, the treatment of CRE spectra is particularly difficult due to the large uncertainty inherent in modeling their sources and propagation [47][48][49]. In this section we discuss how we take account of these uncertainties by performing a large scan over some of the astrophysical parameters used to model cosmic-ray propagation, thereby creating JHEP01(2011)064 a variety of astrophysical background spectra that we regard as internally consistent and plausible with respect to relevant astrophysical measurements.…”

Froggatt-Nielsen model for leptophilic scalar dark matter decay

“…We assume the MED propagation model described in Ref. [17]. The diffusion coefficient and the energy loss rate are assumed to be spatially constant throughout the diffusion zone and are given by 5) where ǫ = E/1 GeV.…”

“…(3.6). As in the case of e ± propagation, the antiproton number density can be expressed in terms of a Green's function 17) where Gp(T, T ′ ) can be found in Ref. [20].…”

“…[17], we compute the antiproton flux and the antiproton to proton ratio for dark matter decays to µ − µ + and µ − µ + h, shown in Fig. 4, and for decays to τ − τ + and τ − τ − h, shown in Fig.…”

Dark matter annihilation rate with nonstandard thermal history

“…The parameters of the second set which are not known with precision are B and the factors that enter the diffusion length, K 0 and δ. For the latter set, we will study the exemplar models from recent dark matter literature, which are outlined in [25] and [26]. We considered three standard halo profiles, NFW, Moore and IsoT, and three positron diffusion models, denoted "min," "med," and "max".…”