Bulletin of the American Physical Society
APS April Meeting 2018
Volume 63, Number 4
Saturday–Tuesday, April 14–17, 2018; Columbus, Ohio
Session D15: Indirect Dark Matter Searches |
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Sponsoring Units: DAP DPF Chair: Tim Linden, Ohio State University Room: B230-231 |
Saturday, April 14, 2018 3:30PM - 3:42PM |
D15.00001: Dark Matter Searches in Dwarf Spheroidal Galaxies and the Virgo Cluster with HAWC Tolga Yapici The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view observatory sensitive to 500 GeV - 100 TeV gamma rays and cosmic rays. It can perform diverse indirect searches for dark matter sugnature in dwarf spheroidal galaxies, which are expected to have few astrophysical sources of gamma rays but high dark matter content, and in the spatially extended galaxy clusters, which are rich in baryonic matter and dark matter. We present annihilation cross section and decay lifetime limits for 15 dwarf spheroidal galaxies within the field-of-view, as well as their combined limit. We also present the HAWC flux upper limits of 15 dwarf galaxies in energy bins. We performed another search for dark matter signature for the Virgo Cluster, the nearest galaxy cluster. We investigated for possible dark matter morphologies and we present limits on annihilation cross section and decay lifetime with the Virgo Cluster. [Preview Abstract] |
Saturday, April 14, 2018 3:42PM - 3:54PM |
D15.00002: All-Sky Dark Matter Annihilation Limits with HAWC Joseph Lundeen The High Altitude Water Cherenkov Observatory (HAWC) is a high energy (500 GeV to 100 TeV) gamma ray detector located in southern Mexico. HAWC operates via the water Cherenkov technique and has both a wide ( 2 sr) field of view and near continuous duty cycle, making it ideal for unbiased sky surveys. We use the HAWC 2HWC catalog from 507 days of observations to perform such a search for dark matter annihilation signals in the observed HAWC sky. We perform both a targeted search of HAWC sources which have no known association with lower-energy counterparts as well as an unbiased search of the entire sky. We use these results to set upper limits on dark matter annihilation across the sky. [Preview Abstract] |
Saturday, April 14, 2018 3:54PM - 4:06PM |
D15.00003: Searching for TeV signatures of cosmic ray interaction and dark matter near the Sun with HAWC Observatory Mehr Un Nisa Very high energy gamma rays from the quiescent Sun have been observed up to almost a 100 GeV. The most likely origin of this emission lies in the pion decay resulting from galactic cosmic rays interacting in the Sun’s atmosphere. Another proposed source of the flux is dark matter annihilation through mediators that decay just outside the Sun into standard model particles. Both models predict that gamma-ray emission should continue above 1 TeV. Measurements of the Sun in the TeV range can help constrain the origin of very high-energy solar gamma rays. The High Altitude Water Cherenkov (HAWC) Observatory is a wide field-of-view array that is currently the only detector capable of measuring gamma rays from the Sun at multi-TeV energies. We present results from a search for excess gamma rays from the Sun using three years of data from HAWC. Our measurements provide the strongest upper limits on TeV gamma rays from the solar disk. We discuss the implications of these measurements on the origin of the solar gamma-ray excess. [Preview Abstract] |
Saturday, April 14, 2018 4:06PM - 4:18PM |
D15.00004: Searching for Dark Matter in M31 with the High Altitude Water Cherenkov Observatory Andrea Albert There is overwhelming evidence that non-baryonic dark matter constitutes ~85\% of the mass in the Universe. Many promising dark matter candidates, like Weakly Interacting Massive Particles (WIMPs), are predicted to produce Standard Model particles like gamma rays via annihilation or decay. These gamma-rays would be observed by ground-based arrays like the High Altitude Water Cherenkov (HAWC) Observatory. With its wide field of view and constant monitoring, HAWC is well-suited to search for dark matter in extended targets like the M31 galaxy. We will present results from our search for a signal from dark matter annihilation or decay in M31 using 760 days of data from HAWC. A detection of dark matter through cosmic messengers would not only confirm the existence of dark matter through a non-gravitational force, but also indicate the existence of physics beyond the Standard Model. [Preview Abstract] |
Saturday, April 14, 2018 4:18PM - 4:30PM |
D15.00005: Searches for Dark Matter in the Galactic Halo with the High Altitude Water Cherenkov Observatory J. Patrick Harding With its observations over 2/3 of the sky every day, the High Altitude Water Cherenkov (HAWC) observatory is sensitive to a wide variety of astrophysical sources, including possible gamma rays from dark matter. Dark matter annihilation and decay in the dark matter halo of the Milky Way Galaxy should produce gamma-ray signals which are spatially extended on the sky. We present a limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo from 15 months of HAWC data. These are some of the most robust limits on TeV and PeV dark matter and are largely insensitive to the dark matter morphology. In particular, we show that these limits can constrain dark matter models in which PeV IceCube neutrinos are explained by dark matter which primarily decays into hadrons. [Preview Abstract] |
(Author Not Attending)
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D15.00006: Abstract Withdrawn
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Saturday, April 14, 2018 4:42PM - 4:54PM |
D15.00007: Reverse Direct Detection: Cosmic Ray Tests of Light Dark Matter Elastic Scattering Christopher Cappiello, Kenny Ng, John Beacom Many dark matter studies have considered indirect detection ($\chi\chi\rightarrow f f$), direct detection ($\chi f\rightarrow \chi f$), and collider searches ($f f\rightarrow \chi \chi$). We propose a new strategy in searching for dark matter elastic cross section by considering cosmic-ray propagation in the galactic dark matter halo. We find that cosmic rays can lose significant fraction of their energy through scattering with dark matter ($f \chi \rightarrow f \chi$). Using existing cosmic-ray data and a simple cosmic-ray propagation model, we study the qualitative effects of dark matter scattering on cosmic-ray propagation and obtain new constraints of dark matter elastic cross sections on light dark matter (keV--GeV), a regime that is difficult for traditional direct detection experiments to probe. [Preview Abstract] |
Saturday, April 14, 2018 4:54PM - 5:06PM |
D15.00008: Sommerfeld Enhancement in Radiative neutrino Mass Models with Large Scalar Multiplets Salah Nasri, Talal Chowdhury We investigate the Sommerfeld enhanced Dark Matter (DM) annihilation cross sections into $WW$, $ZZ$, $\gamma\gamma$ and $\gamma Z$ at present day in the galactic halo for DM candidates in models of Radiative Neutrino Mass generation with large electroweak multiplets. Firstly, we focus on scalar DM of one-loop radiative neutrino mass model (Scotogenic Model) and study the annihilation cross-sections for scalar doublet and its immediate generalization, the quartet in their respective viable region of parameter space. Secondly, we consider fermionic DM of three-loop radiative neutrino mass model (Krauss-Nasri-Trodden Model) and study the annihilation cross-sections for 5-plet and 7-plets respectively. In both cases, we find that larger multiplets have sizable Sommerfeld enhanced cross-sections compared to the smaller multiplets and are more constrained by the current H.E.S.S. observation and future CTA sensitivity limits. [Preview Abstract] |
Saturday, April 14, 2018 5:06PM - 5:18PM |
D15.00009: Comparison and detection of different models of dark matter Chen Xiao-Fan Comparison and detection of different models of dark matter are made. [Preview Abstract] |
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