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We use multimessenger observations of the neutron star merger event GW170817 to derive new constraints on axionlike particles (ALPs) coupling to photons. ALPs are produced via Primakoff and photon coalescence processes in the merger, escape the remnant, and decay back into two photons, giving rise to a photon signal approximately along the line of sight to the merger. We analyze the spectral and temporal information of the ALP-induced photon signal and use the Fermi Large Area Telescope (Fermi-LAT) observations of GW170817 to derive our new ALP constraints. We also show the improved prospects with future MeV γ-ray missions, taking the spectral and temporal coverage of Fermi-LAT as an example.
RESUMO
We propose a new way to probe nonstandard interactions (NSI) of neutrinos with matter using the ultrahigh energy (UHE) neutrino data at current and future neutrino telescopes. We consider the Zee model of radiative neutrino mass generation as a prototype, which allows two charged scalars-one SU(2)_{L} doublet and one singlet, both being leptophilic, to be as light as 100 GeV, thereby inducing potentially observable NSI with electrons. We show that these light charged Zee scalars could give rise to a Glashow-like resonance feature in the UHE neutrino event spectrum at the IceCube neutrino observatory and its high-energy upgrade IceCube-Gen2, which can probe a sizable fraction of the allowed NSI parameter space.
RESUMO
Many new physics scenarios beyond standard model often necessitate the existence of a (light) neutral scalar H, which might couple to the charged leptons in a flavor violating way, while evading all existing constraints. We show that such scalars could be effectively produced at future lepton colliders, either on shell or off shell depending on their mass, and induce lepton flavor violating (LFV) signals, i.e., e^{+}e^{-}ââ_{α}^{±}â_{ß}^{∓}(+H) with α≠ß. We find that a large parameter space of the scalar mass and the LFV couplings can be probed well beyond the current low-energy constraints in the lepton sector. In particular, a scalar-loop induced explanation of the long-standing muon g-2 anomaly can be directly tested in the on-shell mode.
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We show that the excess events observed in a number of recent LHC resonance searches can be simultaneously explained within a nonsupersymmetric left-right inverse seesaw model for neutrino masses with W_{R} mass around 1.9 TeV. The minimal particle content that leads to gauge coupling unification in this model predicts g_{R}≃0.51 at the TeV scale, which is consistent with data. The extra color singlet, SU(2)-triplet fermions required for unification can be interpreted as the dark matter of the Universe. Future measurements of the ratio of same-sign to opposite-sign dilepton events can provide a way to distinguish this scenario from the canonical cases of type-I and inverse seesaw, i.e., provide a measure of the relative magnitudes of the Dirac and Majorana masses of the right-handed neutrinos in the SU(2)_{R} doublet of the left-right symmetric model.
RESUMO
Extending the minimal supersymmetric standard model to explain small neutrino masses via the inverse seesaw mechanism can lead to a new light supersymmetric scalar partner which can play the role of inelastic dark matter (IDM). It is a linear combination of the superpartners of the neutral fermions in the theory (the light left-handed neutrino and two heavy standard model singlet neutrinos) which can be very light with mass in ~5-20 GeV range, as suggested by some current direct detection experiments. The IDM in this class of models has keV-scale mass splitting, which is intimately connected to the small Majorana masses of neutrinos. We predict the differential scattering rate and annual modulation of the IDM signal which can be testable at future germanium- and xenon-based detectors.