Browsing by Author "Olinto, Angela V."
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Item Neutrino constraints on long-lived heavy dark sector particle decays in the Earth(2021-07-02) Reno, Mary Hall; Anchordoqui, Luis A.; Bhattacharya, Atri; Cummings, Austin; Eser, Johannes; Guépin, Claire; Krizmanic, John F.; Olinto, Angela V.; Paul, Thomas; Sarcevic, Ina; Venters, Tonia M.Recent theoretical work has explored dark matter accumulation in the Earth and its drift towards the center of the Earth that, for the current age of the Earth, does not necessarily result in a concentration of dark matter (χ) in the Earth's core. We consider a scenario of long-lived (τχ∼10²⁸ s), super heavy (mχ=10⁷−10¹⁰ GeV) dark matter that decays via χ→ντH or χ→νμH. We show that an IceCube-like detector over 10 years can constrain a dark matter density that mirrors the Earth's density or has a uniform density with density fraction ϵρ combined with the partial decay width Bχ→ντHΓχ in the range of (ϵρ/10⁻¹⁰)Bχ→ντΓχ≲3×10⁻²⁹−3×10⁻²⁸ s⁻¹. For χ→νμH, mχ=10⁸−10¹⁰ GeV and Eμ>10⁷ GeV, the range of constraints is (ϵρ/10⁻¹⁰)Bχ→νμΓχ≲6×10⁻²⁹−1.4×10⁻²⁷ s⁻¹.Item POEMMA’s target of opportunity sensitivity to cosmic neutrino transient sources(2019-06-19) Venters, Tonia M.; Reno, Mary Hall; Krizmanic, John F.; Anchordoqui, Luis A.; Gu´epin, Claire; Olinto, Angela V.We calculate the sensitivity of space-based cosmic neutrino detection from transient sources in the context of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission using Targetof Opportunity (ToO) observations. POEMMA uses two spacecraft each with a large Schmidt telescope to simultaneously view the optical signals generated by extensive air showers (EASs). POEMMA is designed for both ultrahigh-energy cosmic ray and very-high-energy neutrino measurements. POEMMA has significant neutrino sensitivity starting in the 10 PeV decade via measurements of Cherenkov signals from upward-moving EASs initiated by tau neutrinos interacting in the Earth. For ToO observations, POEMMA uses the ability to quickly repoint (90⁰ in 500 seconds) each of the two spacecraft to the direction of the transient source. POEMMA EAS measurements are performed during astronomical night, leading to different observational constraints for shortand long-duration bursts. For short-bursts of order 10³s, POEMMA will increase the sensitivity of existing experiments (e.g., IceCube and the Pierre Auger Observatory) by up to two orders of magnitude. For long-duration bursts on the scale of 10⁵-⁶s, the full celestial sky is available and the average neutrino sensitivity will be increased by up to a factor of 50, reaching the desired level to probe model predictions of transient neutrino sources (e.g., of blazar flares as well as both black hole-black hole and neutron star-neutron star mergers). POEMMA’s neutrino sensitivity to various models of transient neutrino sources are detailed. Altogether, our results demonstrate better sensitivity to ToO neutrino sources from the space-based POEMMA experiment compared to current ground-based experiments, and more importantly, demonstrate unique full-sky coverage for ToO neutrino sources.Item Probing the properties of superheavy dark matter annihilating or decaying into neutrinos with ultra-high energy neutrino experiments(Proceedings of Science, 2021-07-12) Guépin, Claire; Aloisio, Roberto; Anchordoqui, Luis A.; Cummings, Austin; Krizmanic, John F.; Olinto, Angela V.; Reno, Mary Hall; Venters, Tonia M.The evidence for dark matter particles, X, is compelling based on Galactic to cosmological scale observations. Thus far, the promising weakly interacting massive particle scenario have eluded detection, motivating alternative models of dark matter. We consider scenarios involving superheavy dark matter (SHDM) that potentially can decay or annihilate to neutrinos and antineutrinos. In the mass range mₓ = 10⁷ − 10¹⁵ GeV, we evaluate the sensitivities of future observatories POEMMA and GRAND for indirect dark matter detection via the measurement of neutrino-induced extensive air showers (EAS), compute the Auger and ANITA limits using their last up-to-date sensitivities, and compare them with IceCube limits. We also show that the uncertainties related to the dark matter distribution in the Galactic halo have a large impact on the neutrino flux. We show that a ground-based radio detector such as GRAND can achieve high sensitivities due to its large effective area and high duty cycle. Space-based Cherenkov detectors such as POEMMA that measure the EAS optical Cherenkov signal have the advantage of full-sky coverage and rapid slewing, enabling an optimized SHDM observation strategy focusing on the Galactic Center. We show that increasing the field of view of the Cherenkov detectors can significantly enhance the sensitivity. Moreover, POEMMA’s fluorescence observation mode that measures EAS above 20 EeV will achieve state-of-the-art sensitivity to SHDM properties at the highest mass scales