307 research outputs found

    Higgsino Dark Matter in High-Scale Supersymmetry

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    We study a supersymmetric (SUSY) Standard Model in which a Higgsino is light enough to be dark matter, while the other SUSY particles are much heavier than the weak scale. We carefully treat the effects of heavy SUSY particles to the Higgsino nature, especially taking into account the renormalization effects due to the large hierarchy between the Higgsino and the SUSY breaking scales. Inelastic scattering of the Higgsino dark matter with a nucleus is studied, and the constraints on the scattering by the direct detection experiments are discussed. This gives an upper limit on the new physics scale. Bounds on the dark matter-nucleon elastic scattering, the electric dipole moments, and direct production of Higgsinos, on the other hand, give a lower limit. We show the current status on the limits and discuss the future prospects.Comment: 28 pages, 12 figures. Version accepted for publication in JHE

    Electroweakly-Interacting Dirac Dark Matter

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    We consider a class of fermionic dark matter candidates that are charged under both the SU(2)L_L and U(1)Y_Y gauge interactions. In this case a certain amount of dark matter-Higgs couplings, which can split the dark matter into a pair of Majorana fermions, should be present to evade the constraints from the dark matter direct detection experiments. These effects may be probed by means of the dark matter-nucleus scattering via the Higgs-boson exchange process, as well as the electric dipole moments induced by the dark matter and its SU(2)L_L partner fields. In this article, we evaluate them with an effective field approach. It turns out that the constraints coming from the experiments for the quantities have already restricted the dark matter with hypercharge Yβ‰₯3/2Y\geq 3/2. Future experiments have sensitivities to probe this class of dark matter candidates, and may disfavor the Yβ‰₯1Y\geq 1 cases if no signal is observed. In this case, only the Y=0Y=0 and 1/21/2 cases may be the remaining possibilities for the SU(2)L_L charged fermionic dark matter candidates.Comment: 5 pages, 3 figure

    Probing Bino-Wino Coannihilation at the LHC

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    We study bino-wino coannihilation scenario in the so-called spread or mini-split supersymmetry. We show that, in this model, a neutral wino has a macroscopic decay length in a wide range of parameter space. This characteristic feature could be observed as a displaced vertex plus missing transverse energy event at the LHC. In this paper, we study the current constraints and future prospects on the scenario based on the displaced vertex search performed by the ATLAS collaboration. It is found that a sizable parameter region can be probed at the 8 TeV LHC run. This search strategy will considerably extend its reach at the next stage of the LHC running, and thus play a crucial role to examine a possibility of bino dark matter in the mini-split type supersymmetric models.Comment: 21 pages, 7 figures; version accepted for publication in JHE

    Grand Unification, Axion, and Inflation in Intermediate Scale Supersymmetry

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    A class of supersymmetric grand unified theories is introduced that has a single scale below the cutoff, that of the supersymmetry breaking masses m~\tilde{m}. For a wide range of the dimensionless parameters, agreement with the observed mass of the Higgs boson determines m~∼109βˆ’1013GeV\tilde{m} \sim 10^9-10^{13} {\rm GeV}, yielding Intermediate Scale Supersymmetry. We show that within this framework it is possible for seesaw neutrino masses, axions, and inflation to be described by the scale m~\tilde{m}, offering the possibility of a unified origin of disparate phenomena. Neutrino masses allowing for thermal leptogenesis can be obtained, and the axion decay constant lies naturally in the range fa∼109βˆ’1011GeVf_a \sim 10^9-10^{11} {\rm GeV}, consistent with a recent observational suggestion of high scale inflation. A minimal SU(5)SU(5) model is presented that illustrates these features. In this model, the only states at the grand unified scale are those of the heavy gauge supermultiplet. The grand unified partners of the Higgs doublets have a mass of order m~\tilde{m}, leading to the dominant proton decay mode pβ†’Ξ½Λ‰K+p \rightarrow \bar{\nu} K^+, which may be probed in upcoming experiments. Dark matter may be winos, with mass environmentally selected to the TeV scale, and/or axions. Gauge coupling unification is found to be successful, especially if the wino is at the TeV scale.Comment: 27 pages, 7 figures; minor corrections, references and discussion adde
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