292 research outputs found

    Quintessence Saves Higgs Instability

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    We study a model where quintessence potential eξϕe^{-\xi\phi} coupled to Higgs potential. We calculate the evolution of the quintessence, and track the running of the effective Higgs self-coupling. We find it slightly larger than that of the standard model in the past. Requiring the electroweak vacuum to be absolutely stable in inflationary era, we find a lower bound ξ>0.35±0.05\xi> 0.35\pm 0.05, where the uncertainty is mainly from the measurement of the top quark mass. This lower bound, together with the upper bound from the observation for dark energy ξ0.6\xi\lesssim0.6, narrows down the parameter space and makes it possible to test this model in the near future. Interestingly, the bound on ξ\xi, if actually shown to be the case by observation, supports the recently proposed Swampland Conjecture.Comment: 6 pages, 1 figur

    QCD axion dark matter and the cosmic dipole anomaly

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    There is growing evidence that the cosmic dipole measured from the distant galaxy number-count is not consistent with that of CMB. We find that the QCD axion, a hypothetical particle originating from the spontaneous breaking of the Peccei-Quinn symmetry, could explain this dipole anomaly if it constitutes the dark matter of our universe. This model requires that the Hubble parameter during inflation should be lower than 10710^{7} GeV which indicates low scale inflation.Comment: 6 pages, 2 figures, more references adde

    LHC Search for Right-handed Neutrinos in ZZ^\prime Models

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    We consider right-handed neutrino pair production in generic ZZ^\prime models. We propose a new, model-independent analysis using final states containing a pair of same-sign muons. A key aspect of this analysis is the reconstruction of the RH neutrino mass, which leads to a significantly improved sensitivity. Within the U(1)(BL)3U(1)_{(B-L)_{3}} model, we find that at the HL-LHC it will be possible to probe RH neutrino masses in the range 0.2MNR1.10.2\lesssim M_{N_R} \lesssim 1.1\,TeV.Comment: 6 pages, 5 figure