What if dark matter gamma-ray lines come with gluon lines?

Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMIn dark matter (DM) models, the production of a γ line (or of a ‘‘box-shaped’’ γ-ray spectrum) from DM annihilation proceeds in general from a loop diagram involving a heavy charged particle. If the charged particle in the loop carries also a color charge, this leads inevitably to DM annihilation to gluons, with a naturally larger rate. We consider a scenario in which DM candidates annihilate dominantly into gluon pairs, and determine (as far as possible, model-independent) constraints from a variety of observables: (a) the dark matter relic density, (b) the production of antiprotons, (c) DM direct detection and (d) gluon-gluon fusion processes at LHC. Among other things, we show that this scenario together with the recent claim for a possible γ line from the Galactic center in the Fermi-LAT data, leads to a relic abundance of DM that may be naturally close to the cosmological observationsOne of us (M. T.) acknowledges stimulating discussions with Y. Mambrini and U. Ellwanger, and the LPT-Orsay for hospitality. T.H. thanks the Departamento de Física Teórica (UAM-Madrid) and the IFT-Madrid for hospitality and the Comunidad de Madrid (Proyecto HEPHACOS S2009/ESP-1473). This work is supported by the FNRS, the IISN and an ULB-AR

Scalar dark matter models with significant internal bremsstrahlung

“…This in turn would imply that the annihilation rate into gamma rays is fixed by (31) a possibility very much in the spirit of the scenario considered in [14]. We will address such processes with gluons and quarks in final states in a work in progress, as well as the constraints from the measurements of the antiproton flux in cosmic rays, see e.g.…”

“…We will address such processes with gluons and quarks in final states in a work in progress, as well as the constraints from the measurements of the antiproton flux in cosmic rays, see e.g. [11,14]. A second interesting aspect in scalar dark matter models coupled to heavy vector-like quarks is direct detection.…”

“…Since DM is neutral, its annihilation in γγ should proceed through radiative corrections, and so is a priori suppressed by a factor ∝ α 2 < ∼ 10 −4 compared to annihilation into fermion or gauge boson pairs, ff or W W , which not only are supposed to determine the relic abundance but also lead to a large γ ray continuum. However this is not a no-go theorem and following the recent claim of a possible excess of gamma rays around E γ ∼ 130 GeV in the Fermi telescope data [7,8], much works have been dedicated to find new ways to circumvent this conclusion [9][10][11][12][13][14][15][16][17][18] (see also [19][20][21][22][23][24]). Despite the apparent fading of the significance of the signal [5], we believe that it remains of interest to look for further alternative scenarios.…”

Enhanced diphoton rates at Fermi and the LHC

“…Radio telescopes might help to confirm or rule out the dark matter interpretation of the line soon [32]. While the origin of the γ-ray line from the galactic center still has to be clarified, a noticeable amount of theoretical interest has been triggered [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. If interpreted in terms of dark matter, the γ-ray line requires a rather large annihilation cross section into photons, σv γγ ∼ 10 −27 cm 3 s −1 , if one assumes an Einasto profile [22].…”

Gamma rays from top-mediated dark matter annihilations

“…To avoid the overwhelming 1-loop annihilations into gluons [37,43,44], we focus on the case where DM has vector-like couplings with Z . Although we are forced to live in a regime of relatively small mixing angles by the EW precision constraints, we can still have large annihilation cross sections into gamma ray lines, as shown in Figures 10, 11 and 12.…”