Cosmic coincidence and asymmetric dark matter in a Stueckelberg extension

Abstract

We discuss the possibility of the cosmic coincidence generating the ratio of baryon asymmetry to dark matter in a Stueckelberg U (1) extension of the standard model and of the minimal supersymmetric standard model. For the U (1) we choose L µ −L τ which is anomaly free and can be gauged. The dark matter candidate arising from this extension is a singlet of the standard model gauge group but is charged under L µ −L τ . Solutions to the Boltzmann equations for relics in the presence of asymmetric dark matter are discussed. It is shown that the ratio of the baryon asymmetry to dark matter consistent with the current WMAP data, i.e., the cosmic coincidence, can be successfully explained in this model with the depletion of the symmetric component of dark matter from resonant annihilation via the Stueckelberg gauge boson. For the extended MSSM model it is shown that one has a two component dark matter picture with asymmetric dark matter being the dominant component and the neutralino being the subdominant component (i.e., with relic density a small fraction of the WMAP cold dark matter value). Remarkably, the subdominant component can be detected in direct detection experiments such as SuperCDMS and XENON-100. Further, it is shown that the class of Stueckelberg models with a gauged L µ − L τ will produce a dramatic signature at a muon collider with the σ(µis devoid of this resonance. Within the above frameworks we discuss several broad classes of models both above and below the electroweak phase transition temperature. Asymmetric dark matter arising from a U (1) B−L Stueckelberg extension is also briefly discussed. Finally, in the models we propose the asymmetric dark matter does not oscillate and there is no danger of it being washed out from oscillations.

Baryogenesis from dark matter

“…Our model is significantly different from this work and further we also discuss the genesis of asymmetric dark matter as arising from the decay of the primordial fields. The symmetric component of dark matter is depleted by mechanisms similar to those discussed in [5].…”

“…Of course there are other possible choices for T int where W tran would decouple (see [5] for a comprehensive discussion). To determine the generation of lepton number and baryon number from the couplings of the dark sector to the visible sector we use the standard thermal equilibrium method introduced in [19].…”

“…There is an important subtlety here that although the total dark particle number is fixed after the asymmetry transfer interaction decouples, the total baryon number keeps changing because of the sphaleron processes. As was explained in [5], the total baryon number to be used in this formula is B final after the sphaleron processes decouple. Using Eq.…”

“…The dissipation of the symmetric component of dark matter can be achieved by gauge kinetic energy mixing [21] of Uð1Þ x and Uð1Þ Y and via Stueckelberg mass mixing [22][23][24]. Thus dissipation of the thermally produced X, X 0 :X,X 0 and their antiparticles occurs from their annihilation via the Z 0 x boson exchange coupled with a BreitWigner pole enhancement [5,[25][26][27][28]. We are able to deplete sufficient amounts of the symmetric component of dark matter (so it is less than 10% of the total dark matter relic density) with a mixing between Uð1Þ x and Uð1Þ Y as low as $ 0:001 [5] (where is the mixing angle) in the desired mass region of dark matter.…”

Muon g-2 and LHC phenomenology in the L μ − L τ gauge symmetric model

“…If the gauge boson couples to the muon but not to the electron nor quarks, the gauge interaction can explain muon g-2 while keeping the consistency with the direct search results. A simple candidate is based on anomaly free L µ − L τ gauge symmetry [26][27][28][29][30][31][32], where L µ and L τ are µ and τ lepton numbers, respectively. We consider this model in detail.…”