130 GeV gamma-ray line and generic dark matter model building constraints from continuum gamma rays, radio, and antiproton data

Abstract

An analysis of the Fermi gamma-ray space telescope data has recently revealed a resolved gamma-ray feature close to the galactic center which is consistent with monochromatic photons at an energy of about 130 GeV. If interpreted in terms of dark matter (DM) annihilating into (Z, h), this would correspond to a DM particle mass of roughly 130 GeV (145 GeV, 155 GeV). The rate for these loop-suppressed processes, however, is larger than typically expected for thermally produced DM. Correspondingly, one would generically expect even larger tree-level production rates of standard model fermions or gauge bosons. Here, we quantify this expectation in a rather model-independent way by relating the tree level and loop amplitudes with the help of the optical theorem. As an application, we consider bounds from continuum gamma rays, radio, and antiproton data on the tree-level amplitudes and translate them into constraints on the loop amplitudes. We find that, independently of the DM production mechanism, any DM model aiming at explaining the line signal in terms of charged standard model particles running in the loop is in rather strong tension with at least one of these constraints, with the exception of loops dominated by top quarks. We stress that attempts to explain the 130 GeV feature with internal bremsstrahlung do not suffer from such difficulties.

Sharp gamma-ray spectral features from scalar dark matter annihilations

“…We have checked that our full expression of iM γγ satisfies the Ward identity, and we also cross-checked the imaginary part of A γγ with the one deduced from the optical theorem [64]. In the limit → 0, one can explicitly evaluate all PassarinoVeltman functions in eq.…”

Gravity-mediated (or composite) Dark Matter confronts astrophysical data

“…But, the corresponding process is loop-suppressed as compared to the tree-level processes, so it is challenging to build a microscopic model for dark matter interactions . Furthermore, the tree-level DM annihilations have been strongly constrained by the gamma-ray searches [32][33][34][35][36][37][38][39][40][41][42][43] and anti-proton bounds [44][45][46]. Independent of whether the Fermi gamma-ray line survives more data, the gamma-ray constraints are getting more important for dark matter model building in general.…”

Composite Higgsino

“…In addition to the line-gamma constraints, we should also take into account the constraints from continuum gamma-ray and other cosmic-ray observations [53][54][55][56][57] for the Higgsino dark matter scenario because of the large annihilate cross section to weak gauge bosons, (σv) W W (ZZ) ∼ 2.1(1.8) × 10 −25 cm 3 s −1 at µ ∼ 140 GeV pure Higgsino region in MSSM [58]. But, there are also uncertainties and because the ratio of the W W (ZZ) cross section to γZ cross section is not determined, unlike the wino and Higgsino case in MSSM [54], the possibility for the composite Higgsino as the origin of the tentative gamma-line like signal cannot be excluded by a dark matter distribution independent way.…”