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We explore G x G unified theories with the visible and the hidden or dark sectors paired under a Z2 symmetry. Developing a system of "asymmetric symmetry breaking" we motivate such models on the basis of their ability to generate dark baryons that are confined with a mass scale just above that of the proton, as motivated by asymmetric dark matter. This difference is achieved from the distinct but related confinement scales that develop in unified theories that have the two factors of G spontaneously breaking in an asymmetric manner. We show how Higgs potentials that admit different gauge group breaking chains in each sector can be constructed, and demonstrate the capacity for generating different fermion mass scales. Lastly we discuss supersymmetric extensions of such schemes. [ABSTRACT FROM AUTHOR]

Abstract: In a baryon-symmetric universe, the baryon asymmetry observed for visible matter is matched by an equal and opposite asymmetry for dark matter, thereby closely connecting the number densities of both types of matter. This is a necessary step towards the goal of explaining the mystery of why the visible and dark matter densities are observed to be similar. In this talk, a way of producing such a universe from bubble nucleation during a first-order phase transition is reviewed. The process is an analog of electroweak baryogenesis. [Copyright &y& Elsevier]

Models of asymmetric dark matter (ADM) seek to explain the apparent coincidence between the present-day mass densities of visible and dark matter, ΩDM≃5ΩVM. However, most ADM models only relate the number densities of visible and dark matter without motivating the similar particle masses. We expand upon a recent work that obtained a natural mass relationship in a mirror matter ADM model with two Higgs doublets in each sector, by looking to implement dark electroweak baryogenesis as the means of asymmetry generation. We explore two aspects of the mechanism: the nature of the dark electroweak phase transition, and the transfer of particle asymmetries between the sectors by the use of portal interactions. We find that both aspects can be implemented successfully for various regions of the parameter space. We also analyze one portal interaction--the neutron portal--in greater detail, in order to satisfy the observational constraints on dark radiation. [ABSTRACT FROM AUTHOR]

We analyze restrictions on the stochastic superspace parameter space arising from 1 fb-1 of LHC data, and bounds on sparticle masses, cold dark matter relic density, and the branching ratio of the process Bs→ μ+μ+ A region of parameter space consistent with these limits is found where the stochasticity parameter, &xgr;, takes values in the range --2200 GeV < &xgr; < --900 GeV, provided the cutoff scale is 0(1O18) GeV. [ABSTRACT FROM AUTHOR]

The standard cold dark matter cosmological model, while successful in explaining the observed large scale structure of the Universe, tends to overpredict structure on small scales. It has been proposed this problem may be alleviated in a class of late-decaying dark matter models, in which the parent dark matter particle decays to an almost degenerate daughter, plus a relativistic final state. We construct explicit particle physics models that realize this goal while obeying observational constraints. To achieve this, we introduce a pair of fermionic dark matter candidates and a new scalar field, which obey either a ℤ4 or a U(1) symmetry. Through the spontaneous breaking of these symmetries, and coupling of the new fields to standard model particles, we demonstrate that the desired decay process may be obtained. We also discuss the dark matter production processes in these models. [ABSTRACT FROM AUTHOR]

The idea that dark matter may be a composite state of a hidden non-Abelian gauge sector has received great attention in recent years. Frameworks such as asymmetric dark matter motivate the idea that dark matter may have similar mass to the proton, while mirror matter and G×G grand unified theories provide rationales for additional gauge sectors which may have minimal interactions with standard model particles. In this work we explore the hadronic spectra that these dark QCD models can allow. The effects of the number of light colored particles and the value of the confinement scale on the lightest stable state, the dark matter candidate, are examined in the hyperspherical constituent quark model for baryonic and mesonic states. [ABSTRACT FROM AUTHOR]

The similarity of the visible and dark matter abundances indicates that they may originate via the same mechanism. If both the dark and visible matter are charged under a generalized baryon number, then the asymmetry of the visible sector may be compensated by an asymmetry in the dark sector. We show how the separation of the baryonic and the -antibaryonic charge can originate in the vacuum, via the Affleck-Dine mechanism, due to the breaking of a symmetry orthogonal to the baryon number. Symmetry restoration in the current epoch guarantees the individual stability of the two sectors. [ABSTRACT FROM AUTHOR]