Extra U(1) as natural source of a monochromatic gamma ray line

Abstract

Extensions of the Standard Model with an extra U ′ (1) abelian group generically generate terms coming from loops of heavy fermions, leading to three gauge boson couplings, in particular Z ′ Zγ. We show that WMAP data constrains the gauge coupling of the group g D to values comparable with the electro-weak ones, rather independently of the mass of Z ′ . Moreover, the model predicts a monochromatic γ-ray line which can fit a 130 GeV signal at the FERMI telescope for natural values of the Chern-Simons terms and a dark matter mass around 144.5 GeV.

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].…”

LHC signatures of a Z ′ mediator between dark matter and the SU(3) sector

“…Such scenarios have already been studied in the context of Dark Matter (DM) model building [11,[48][49][50]. In such framework, dimension six operators are suppressed by a factor M 2 (M being the mass of heavy fermions integrated out) and the dark matter sector, charged under U(1) X , couples with the weak or coloured sector of the Standard Model.…”

“…In such framework, dimension six operators are suppressed by a factor M 2 (M being the mass of heavy fermions integrated out) and the dark matter sector, charged under U(1) X , couples with the weak or coloured sector of the Standard Model. An interaction with the weak SM sector was shown to have possible astrophysical signatures [48,49], while a coupling to the coloured SM sector was constrained [11] using mono-jets events at the LHC [52], as well as indirect detection constraints arising from astrophysical measurements. Such couplings had been studied, together with couplings to the top quarks in [53] but only in the context JHEP03(2016)006 Figure 1.…”

Can a millicharged dark matter particle emit an observable γ-ray line?

“…Beside this general class of models, there exist other ways along which DM could emit monochromatic photons. One possibility consists in assuming that the γ-ray line is due to a Z − Z − γ Chern-Simons interaction [7]. Another possibility, much less studied, would be to consider a photon directly emitted by the DM particle.…”