30 research outputs found

    Searching for Flavored Gauge Bosons

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    Standard Model may allow an extended gauge sector with anomaly-free flavored gauge symmetries, such as Liβˆ’LjL_{i} - L_{j}, Biβˆ’LjB_{i} - L_{j}, and Bβˆ’3LiB - 3L_{i}, where i,j=1,2,3i,j=1,2,3 are flavor indices. We investigate phenomenological implications of the new flavored gauge boson Zβ€²Z^{\prime} in the above three classes of gauge symmetries. Focusing on the gauge boson mass above 5 GeV, we use the lepton universality test in the ZZ and Ο„/ΞΌ\tau/\mu decays, LEP searches, LHC searches, neutrino trident production bound, and LHC Zβ†’4ΞΌZ\rightarrow 4\mu searches to put constraints on the gβ€²βˆ’MZβ€²g^{\prime}-M_{Z^{\prime}} plane. When L1L_1 is involved, the LEP bounds on the eβˆ’e+β†’β„“βˆ’β„“+e^{-}e^{+} \rightarrow \ell^{-}\ell^{+} processes give the most stringent bounds, while the LHC bound becomes the strongest constraints in the large MZβ€²M_{Z^{\prime}} region when BiB_{i} is involved. The bound from Zβ†’4ΞΌZ\rightarrow 4\mu productions, which is applicable for L2L_2-involved scenarios, provides stringent bounds in the small MZβ€²M_{Z^{\prime}} region. One exception is the Bβˆ’3L2B-3L_2 scenario, in which case only a small region is favored due to the lepton universality.Comment: v3: updated LHC bounds for B-3L_i model

    Non-thermal WIMP baryogenesis

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    We propose a WIMP baryogensis achieved by the annihilation of non-thermally produced WIMPs from decay of heavy particles, which can result in low reheating temerature. Dark matter (DM) can be produced non-thermally during a reheating period created by the decay of long-lived heavy particle, and subsequently re-annihilate to lighter particles even after the thermal freeze-out. The re-annihilation of DM provides the observed baryon asymmetry as well as the correct relic density of DM. We investigate how wahout effects can affect the generation of the baryon asymmetry and study a model suppressing them. In this scenario, we find that DM can be heavy enough and its annihilation cross section can also be larger than that adopted in the usual thermal WIMP baryogenesis.Comment: 5 pages, 6 figure

    Galactic center GeV gamma-ray excess from dark matter with gauged lepton numbers

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    The recently observed excess in gamma-ray signal near the Galactic center suggests that dark matter particles may annihilate into charged fermions that produce gamma-ray to be observed. In this paper, we consider a leptonic dark matter, which annihilates into the standard model leptons, ΞΌ+ΞΌβˆ’\mu^+ \mu^- and Ο„+Ο„βˆ’\tau^+ \tau^-, by the interaction of the gauged lepton number U(1)LΞΌβˆ’LΟ„{\rm U(1)}_{L_\mu-L_\tau} and fits the observed excess. Interestingly, the necessary annihilation cross section for the observed gamma-ray flux provides a good fit to the value for the relic abundance of dark matter. We identify the preferred parameter space of the model after taking the existing experimental constraints from the precision measurements including the muon (gβˆ’2)(g-2), tau decay, neutrino trident production, dark matter direct detection, LHC, and LEP experiments.Comment: 18 pages, 8 figures, references added, matches published versio

    Non-thermal WIMPy Baryogenesis with Primordial Black Hole

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    We consider the possibility that the weakly interacting massive particles produced from the evaporation of primordial black hole can explain both the relic density of dark matter and the baryon asymmetry of the Universe, through their annihilation which violate B and CP-symmetry. We find that the primordial black hole with mass less than 107g10^7 {\rm g} is a good candidate as an source of TeV dark matter with the total annihilation cross section βŸ¨ΟƒaΟ…βŸ©β‰²10βˆ’7Β GeVβˆ’2\left\langle\sigma_a \upsilon\right\rangle \lesssim 10^{-7} \ {\rm GeV}^{-2} and the B-violating scattering cross section βŸ¨ΟƒBΟ…βŸ©β‰²2Γ—10βˆ’9Β GeVβˆ’2\left\langle\sigma_B \upsilon\right\rangle \lesssim 2\times 10^{-9} \ {\rm GeV^{-2}}. This large annihilation cross section of dark matter in this model would make it available to search them in the indirect search for dark matter such as gamma-ray or neutrino observations
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