We construct a model based on a new U (1) X gauge symmetry and a discrete Z 2 symmetry under which the new gauge boson is odd. The model contains new complex scalars which carry U (1) X charge but are singlets of the Standard Model. The U (1) X symmetry is spontaneously broken but the Z 2 symmetry is maintained, making the new gauge boson a dark matter candidate. In the minimal version there is only one complex scalar field but by extending the number of scalars to two, the model will enjoy rich phenomenology which comes in various phases. In one phase, CP is spontaneously broken. In the other phase, an accidental Z 2 symmetry appears which makes one of the scalars stable and therefore a dark matter candidate along with the vector boson. We discuss the discovery potential of the model by colliders as well as the direct dark matter searches. *

In this paper the stationary Klein–Gordon equation is considered for the Coulomb potential in noncommutative space. The energy shift due to noncommutativity is obtained via the perturbation theory. Furthermore, we show that the degeneracy of the initial spectral line is broken in transition from commutative space to noncommutative space.

We present a dark matter model for explaining the observed 130 GeV photon line from the galaxy center. The dark matter candidate is a vector boson of mass m V with a dimensionless coupling to the photon and Z boson. The model predicts a double line photon spectrum at energies equal to m V and m V (1 − m 2 Z /4m 2 V ) originating from the dark matter annihilation. The same coupling leads to a mono-photon plus missing energy signal at the LHC. The entire perturbative parameter space can be probed by the 14 TeV LHC run. The model has also a good prospect of being probed by direct dark matter searches as well as the measurement of the rates of h → γγ and h → Zγ at the LHC.

We present a Vector Dark Matter (VDM) model that explains the 3.5 keV line recently observed in the XMM-Newton observatory data from galaxy clusters. In this model, dark matter is composed of two vector bosons, V and V , which couple to the photon through an effective generalized Chern-Simons coupling, g V . V is slightly heavier than V with a mass splitting m V − m V 3.5 keV. The decay of V to V and a photon gives rise to the 3.5 keV line. The production of V and V takes place in the early universe within the freeze-in framework through the effective g V coupling when m V < T < Λ, Λ being the cut-off above which the effective g V coupling is not valid. We introduce a high energy model that gives rise to the g V coupling at low energies. To do this, V and V are promoted to gauge bosons of spontaneously broken new U (1) V and U (1) V gauge symmetries, respectively. The high energy sector includes milli-charged chiral fermions that lead to the g V coupling at low energy via triangle diagrams.