Bulletin of the American Physical Society
APS April Meeting 2015
Volume 60, Number 4
Saturday–Tuesday, April 11–14, 2015; Baltimore, Maryland
Session K2: Elementary Particles and Dark Matter |
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Sponsoring Units: DAP Chair: Andrea Albert, Stanford University Room: Holiday 1 |
Sunday, April 12, 2015 1:30PM - 1:42PM |
K2.00001: A Critical Look at the 3.5 keV Line Tesla Jeltema, Stefano Profumo, Eric Carlson We take a critical look at the possible origins of the 3.5 keV line using both spectroscopic analysis of the Galactic Center and M31 and a morphological analysis of the Galactic Center on the Perseus Cluster. In particular, we find that the spatial distribution of 3.5 keV emission in the Galactic Center is incompatible with a dark matter origin, and this allows us to place stringent limits on dark matter decay lines near 3.5 keV in tension with a dark matter explanation of the line seen in clusters and other systems. We do not detect a significant 3.5 keV line in M31. We do detect a line near 3.5 keV in the Galactic Center, but find that its flux could be compatible with astrophysical plasma emission from e.g. K XVIII within the systematic uncertainties. [Preview Abstract] |
Sunday, April 12, 2015 1:42PM - 1:54PM |
K2.00002: Search for Indirect Signals of Dark Matter with The High Altitude Water Cherenkov (HAWC) Observatory Brian Baughman, Patrick Harding The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view observatory sensitive to 100 GeV - 100 TeV gamma rays and cosmic rays. Located at an elevation of 4100 m on the Sierra Negra volcano in Mexico, HAWC observes extensive air showers from gamma rays via their production of Cherenkov light within an array of water tanks. With a wide field-of-view observing 2/3 of the sky each day and a sensitivity of greater than 1 Crab per day, HAWC has the ability to probe a large fraction of the sky for the signals of TeV-mass dark matter. HAWC's sensitivity to dark matter for several astrophysical sources and some early limits from the built detector will be presented. [Preview Abstract] |
Sunday, April 12, 2015 1:54PM - 2:06PM |
K2.00003: Dark matter admixed Type Ia supernovae Shing Chi Leung, Ming Chung Chu, Lap Ming Lin We perform two-dimensional hydrodynamic simulations for the thermonuclear explosion of Chandrasekhar-mass white dwarfs with dark matter (DM) cores in Newtonian gravity. We include a detailed nuclear reaction network and make use of the pure turbulent deflagration model as the explosion mechanism in our simulations. Our numerical results show that the general properties of the explosion depend quite sensitively on the mass of the DM core M$_{\mathrm{DM}}$. A larger M$_{\mathrm{DM}}$ generally leads to a weaker explosion and a lower mass of synthesized iron-peaked elements. In particular, the total mass of $^{56}$Ni produced can drop from about 0.3 to 0.03 M$_{\mathrm{sun}}$ as M$_{\mathrm{DM}}$ increases from 0.01 to 0.03 M$_{\mathrm{sun}}$. We have also constructed the bolometric light curves obtained from our simulations and found that our results match well with the observational data of sub-luminous type Ia supernovae. [Preview Abstract] |
Sunday, April 12, 2015 2:06PM - 2:18PM |
K2.00004: Dark matter sterile neutrinos and supernova explosions MacKenzie Warren, Grant Mathews, Jun Hidaka, Toshitaka Kajino The nature of dark matter and the explosion mechanism of core-collapse supernovae remain two of the biggest questions in astrophysics. A heavy sterile neutrino species may provide a solution to both of these problems. Recent observations of galaxies and galaxy clusters indicate that dark matter may be consistent with a $\sim$keV mass sterile neutrino. In core-collapse supernovae, sterile neutrinos can efficiently transport energy from the protoneutron star core to the stalled shock via oscillations between electron neutrinos and sterile neutrinos. We have performed simulations of core-collapse supernovae including a sterile neutrino with mass and mixing angle of a dark matter candidate. We have found that some choices of mass and mixing angle result in enhanced neutrino reheating and result in successful explosions, even in models that would not otherwise explode. [Preview Abstract] |
Sunday, April 12, 2015 2:18PM - 2:30PM |
K2.00005: Do Dark Matter Axions Form a Condensate with Long-Range Correlation? Chanda Prescod-Weinstein, Mark Hertzberg, Alan Guth Recently there has been significant interest in the claim that dark matter axions gravitationally thermalize and form a Bose-Einstein condensate with cosmologically long-range correlation. This has potential consequences for galactic scale observations. Here we critically examine this claim. We point out that there is an essential difference between the thermalization and formation of a condensate due to repulsive interactions, which can indeed drive long-range order, and that due to attractive interactions, which can lead to localized Bose clumps (stars or solitons) that only exhibit short range correlation. While the difference between repulsion and attraction is not present in the standard collisional Boltzmann equation, we argue that it is essential to the field theory dynamics, and we explain why the latter analysis is appropriate for a condensate. Since the axion is primarily governed by attractive interactions -- gravitation and scalar-scalar contact interactions -- we conclude that the claim of long-range correlation is unjustified. [Preview Abstract] |
Sunday, April 12, 2015 2:30PM - 2:42PM |
K2.00006: Searching for Traces of Planck-Scale Physics with High Energy Neutrinos Floyd Stecker, Sean Scully, Stefano Liberati, David Mattingly High energy cosmic neutrinos provide a sensitive test of Lorentz invariance violation (LIV) as may be a consequence of quantum gravity theories. We consider the effects of LIV on the propagation of high energy neutrinos over cosmological distances using a class of non-renormalizable, Lorentz violating operators in an effective field theory description of LIV. We assume a generic scenario for the redshift distribution of extragalactic neutrino sources and employ Monte Carlo techniques to follow superluminal neutrino propagation. We include kinematically allowed energy losses of superluminal neutrinos caused by both vacuum pair emission (VPE) and neutrino splitting. We compare the spectra that we derive with that obtained by \textit{IceCube} in order to determine the implications of our results regarding Planck-scale physics. We find that if the drop off in the neutrino flux above $\sim$ 2 PeV is caused by LIV a potentially significant pileup effect would be produced just below the drop-off energy in the case of \textit{CPT}-even operator dominance. However, a clear drop off effect would \textit{not} be observed if the \textit{CPT}-odd, \textit{CPT}-violating term dominates. [Preview Abstract] |
Sunday, April 12, 2015 2:42PM - 2:54PM |
K2.00007: Milagro Limits and HAWC Sensitivity for the Rate Density of Evaporating Primordial Black Holes Samuel Marinelli Primordial black holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all energetically allowed species of fundamental particles thermally. PBHs with initial masses of order $5.0\times10^{10}$ g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV -- TeV energy range. The Milagro high-energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field of view, more than 90\% duty cycle, and sensitivity up to 100-TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. A search of five years of Milagro data yielded no detections at $5\sigma$ and set a local (parsec-scale) upper limit of $3.6\times10^4$ PBH bursts/year/pc$^3$. In addition, we will report the sensitivity of the Milagro successor, the High-Altitude Water-Cherenkov (HAWC) observatory, to PBH evaporation events. [Preview Abstract] |
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