Photon, neutrino and charged particle spectra from R-violating gravitino decays

Abstract

We study photonic, neutrino and charged particle signatures from slow decays of gravitino dark matter in supersymmetric theories where R-parity is explicitly broken by trilinear operators. Photons and (anti-)fermions from loop and tree-level processes give rise to spectra with distinct features, which, if observed, can give crucial input on the possible mass of the gravitino and the magnitude and flavour structure of R-violating operators. Within this framework, we make detailed comparisons of the theoretical predictions to the recent experimental data from PAMELA, ATIC and Fermi LAT.1 This power of m 7 G , which plays an important role in our considerations, comes about as follows: there is a factor of m 5 G from phase space, such as in muon decays, in addition, there is a factor of mG in the matrix element, since the gravitational coupling is proportional to the four-momentum.

Antideuteron limits on decaying dark matter with a tuned formation model

“…The expected limit on the L 1 Q 2D2 operator is somewhat weaker than the current limit from antiprotons in Ref. [13] for low gravitino masses, but roughly equal for gravitino masses above a few hundred GeV. For theŪ 1D1D2 operator, the expected limit from AMS-02 is a factor ∼ 1.5 stronger than the current limit for mG = 10 GeV, increasing to a factor ∼ 4 for gravitino masses in the 100 GeV range.…”

“…[13]. For the L 1 Q 3D3 andŪ 3D2D3 operators, the limits disappear when reaching the kinematical thresholds of the corresponding gravitino three-body decays.…”

“…[13] were calculated using Pythia 6.4 for event generation and GALPROP for cosmic ray propagation, with somewhat different propagation model parameters than used in the present study. Differences in the hadronization and propagation model can lead to differences in limits, and this should be kept in mind when comparing the antiproton and antideuteron limits.…”

“…Limits on trilinear couplings have been set on the basis of indirect detection experiments in the antiproton, positron and gamma-ray channels [3,13]. These are generically much stronger than other (collider) limits on RPV couplings, resting only on the assumption that the gravitinos constitute a significant fraction of the total DM.…”

SUSY dark matter(s)

“…The spectra from gravitino decay in bilinear R-parity models have been computed in [132,[136][137][138][139]. In the case of trilinear R-parity breaking, also three-body decays can be important, because the two-body decay only arises at oneloop level [140][141][142]. As for the case of DM annihilation, until now no clear signal for a DM decay has been found so far.…”