Unified TeV scale picture of baryogenesis and dark matter

Department of Physics, Oklahoma State University - Stillwater, SWO, Oklahoma, United States
Physical Review Letters (Impact Factor: 7.73). 05/2007; 98(16):161301. DOI: 10.1103/PHYSREVLETT.98.161301
Source: PubMed

ABSTRACT We present a simple extension of the minimal supersymmetric standard model which provides a unified picture of cosmological baryon asymmetry and dark matter. Our model introduces a gauge singlet field N and a color triplet field X which couple to the right-handed quark fields. The out-of-equilibrium decay of the Majorana fermion N mediated by the exchange of the scalar field X generates adequate baryon asymmetry for MN approximately 100 GeV and MX approximately TeV. The scalar partner of N (denoted N1) is naturally the lightest SUSY particle as it has no gauge interactions and plays the role of dark matter. The model is experimentally testable in (i) neutron-antineutron oscillations with a transition time estimated to be around 10(10)sec, (ii) discovery of colored particles X at LHC with mass of order TeV, and (iii) direct dark matter detection with a predicted cross section in the observable range.

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    ABSTRACT: We discuss a supersymmetric model for cogenesis of dark and baryonic matter where the dark matter (DM) has mass in the 8-10 GeV range as indicated by several direct detection searches, including most recently the CDMS experiment with the desired cross section. The DM candidate is a real scalar field. Two key distinguishing features of the model are the following: (i) in contrast with the conventional weakly interacting massive particle dark matter scenarios where thermal freeze-out is responsible for the observed relic density, our model uses nonthermal production of dark matter after reheating of the Universe caused by moduli decay at temperatures below the QCD phase transition, a feature which alleviates the relic overabundance problem caused by small annihilation cross section of light DM particles and (ii) baryogenesis occurs also at similar low temperatures from the decay of TeV scale mediator particles arising from moduli decay. A possible test of this model is the existence of colored particles with TeV masses accessible at the LHC.
    Physical Review Letters 08/2013; 111(5):051302. DOI:10.1103/PhysRevLett.111.051302 · 7.73 Impact Factor
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    ABSTRACT: The cosmological matter-antimatter asymmetry can arise from the baryon number conserving CP asymmetry in two body decays of heavy particles, when the two final states carry equal and opposite baryon number, and one couples directly or indirectly to electroweak sphalerons so that its baryon asymmetry gets partly reprocessed into a lepton asymmetry, while the other remains chemically decoupled from the thermal bath with its baryon content frozen. After sphaleron switchoff the decay of the decoupled particles inject in the thermal plasma an unbalanced baryon asymmetry, giving rise to baryogenesis. We highlight the features of this mechanism in a type-I seesaw model extended by adding a new colored scalar coupled to the heavy Majorana neutrinos. If the colored scalar has an O(TeV) mass, it would leave at the LHC a characteristic signature throughout all layers of the detectors.
    Journal of Cosmology and Astroparticle Physics 09/2013; 2014(02). DOI:10.1088/1475-7516/2014/02/013 · 5.88 Impact Factor
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    ABSTRACT: In this work we present an analysis of flavor violating effects mediated by color sextet scalars, which arise naturally in left-right symmetric gauge theories based on SU(2)_L \times SU(2)_R \times SU(4)_C group. The sextets, denoted here by \Delta_{dd}, Delta_{ud} and \Delta_{uu}, couple to right--handed quarks. We delineate the constraints on these couplings arising from meson--anti-meson transitions and flavor changing weak decays. The sextet \Delta_{uu} mediates D^{0}-\bar{D}^{0} mixing via tree-level and box diagrams, and also mediates D --> K pi, pi pi decays. The sextets \Delta_{ud} and \Delta_{dd} mediate B_{d}^{0}-\bar{B}_{d}^{0}, B_{s}^{0}-\bar{B}_{s}^{0} and K^{0}-\bar{K}^{0} mixings as well as rare B and D meson decays. Our analysis shows that for coupling strengths of order 10^{-2}, the current experimental data requires the mass of these color sextets to exceed several TeV. These bounds are stronger than those obtained from direct LHC searches.


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