Browsing by Author "Wyenberg, Jason"

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    Active-to-sterile neutrino dipole portal and the XENON1T excess
    Shoemaker, Ian M.; Tsai, Yu-Dai; Wyenberg, Jason (American Physical Society, 2021-12-27)
    In this paper, we find that a magnetic transition dipole moment between tau and sterile neutrinos can account for the XENON1T excess events. Unlike the ordinary neutrino dipole moment, the introduction of the new sterile mass scale allows for astrophysical bounds to be suppressed. Interestingly, the best-fit regions that are compatible with the SN1987A imply either boron-8 as the source flux. We find that sterile neutrinos in the similar to(500-800) keV mass range are capable of evading astrophysical constraints while being able to successfully explain the XENON1T event rate. We also set new constraints on the dipole portal based on the Xenon 1T data. The sterile neutrino in the best fit parameter space may have significant effects on big bang nucleosynthesis (BBN). We show the region in which a low reheating temperature of the Universe may allow the BBN constraints to be alleviated.
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    Dark matter-neutrino interconversion at COHERENT, direct detection, and the early Universe
    Hurtado, Nicholas; Mir, Hana; Shoemaker, Ian M.; Welch, Eli; Wyenberg, Jason (2020-07-14)
    We study a dark matter (DM) model in which the dominant coupling to the standard model occurs through a neutrino-DM-scalar coupling. The new singlet scalar will generically have couplings to nuclei/electrons arising from renormalizable Higgs portal interactions. As a result, the DM particle X can convert into a neutrino via scattering on a target nucleus N: X + N -> nu + N, leading to striking signatures at direct detection experiments. Similarly, DM can be produced in neutrino scattering events at neutrino experiments: nu + N -> X + N, predicting spectral distortions at experiments such as COHERENT. Furthermore, the model allows for late kinetic decoupling of dark matter with implications for small-scale structure. At low masses, we find that COHERENT and late kinetic decoupling produce the strongest constraints on the model, while at high masses the leading constraints come from DM down-scattering at XENON1T and Borexino. Future improvement will come from CavNS data, ultralow threshold direct detection, and rare kaon decays.