Seminar archive 2017

Raw date Event date Title Speakers Host Summary Links
20170123 Jan. 23, 2017, 2:00 pm Coherent Neutrino-Nucleus Scattering: signal of background? The next generation of dark matter direct detection experiments will be sensitive to coherent nuclear scattering of solar neutrinos. This presents an irreducible background to dark matter searches, the so called ‘neutrino floor’. However, this effect that has yet to be observed and so provides an opportunity for discovery. Dedicated experiments are racing to observe... More »
20170130 Jan. 30, 2017, 2:00 pm The ANDES Deep Underground Laboratory in South America: status and prospects The construction of the Agua Negra tunnel through the Andes between Argentina and Chile is a unique opportunity to build a world class deep underground laboratory in the southern hemisphere, with 1750m of rock overburden. At 30 degrees latitude south, far from nuclear power plants, it provides a unique site for Dark Matter searches and... More »
20170206 Feb. 6, 2017, 2:00 pm Discovery of the First Quad(-like) Lensed Quasar System in the Dark Energy Survey Strong gravitational lensing systems provide valuable tools for studying the properties and evolution of galaxies and quasars, for measuring the distribution of dark matter, and for constraining cosmological parameters. In particular, lensed quasar systems, when accompanied by accurate time delay measurements and careful lens modeling, can provide powerful cosmological constraints that are complementary to those... More »
20170213 Feb. 13, 2017, 2:00 pm Canceled
20170220 Feb. 20, 2017, 2:00 pm Cross-Correlating 2D and 3D Galaxy Surveys Galaxy surveys probe both structure formation and the expansion rate, making them promising avenues for understanding the dark universe. Photometric surveys accurately map the 2D distribution of galaxy positions and shapes in a given redshift range, while spectroscopic surveys provide sparser 3D maps of the galaxy distribution. In this talk, I will present a way... More »
20170227 Feb. 27, 2017, 2:00 pm Interplay between dark and baryonic matter in galaxy centers: new constraints from dynamics and lensing The central 5-10 kpc of elliptical galaxies, while in long term steady state, are not truly relaxed. The primary reason is that baryons and dark matter are not fully mixed with each other. We demonstrate this by comparing observed and simulated galaxies to theoretically derived prediction for dynamically relaxed collisionless systems, and by examining the... More »
20170306 March 6, 2017, 2:00 pm Direct Detection of sub-GeV Dark Matter Dark matter with MeV-to-GeV masses is a theoretically and phenomenologically appealing possibility. In this talk, I will describe how direct-detection experiments can probe this under-explored mass range. A demonstrated technique with significant potential for improvement is that dark matter scatters off electrons, causing ionization or excitation of atoms in a detector target material, which can... More »
20170313 March 13, 2017, 2:00 pm Cores in Dwarf Galaxies from Fermi Repulsion James Unwin, UIC Cold dark matter provides a remarkably good description of cosmology and astrophysics. However, observations connected with small scales might be in tension with this framework. In particular, structure formation simulations suggest that the density profiles of dwarf spheroidal galaxies should exhibit cusps, in contrast to observations. I will show that Fermi repulsion can explain the... More »
20170320 March 20, 2017, 2:00 pm Compact dark matter Marc Kamionkowski, Johns Hopkins Considerable attention has focused the past year on the possibility that some or all of the dark matter could be composed of compact dark objects with masses around 30 solar masses.  The hypothesis has led to interesting connections to gravitational-wave astrophysics, fast radio bursts, pulsar timing arrays, galaxy surveys, gravitational lensing, and stellar dynamics.  I... More »
20170327 March 27, 2017, 2:00 pm Weyl Symmetry, Inflation, and Spontaneous Generation of the Planck Mass Christopher Hill, Fermilab Scalar fields can be coupled non-minimally to curvature and satisfy: (i) the theory has no mass input parameters, including M_Planck=0; (ii) the scalars have arbitrary values and gradients, but undergo a general expansion and relaxation to constant values that satisfy a nontrivial elliptical constraint K(phi)=constant; (iii) this constraint breaks scale symmetry spontaneously, and the Planck... More »
20170403 April 3, 2017, 2:00 pm New Insights into the Cosmic-Ray Positron Excess Dan Hooper, Fermilab Recent Measurements of the Gaming and B0656+14 pulsars by the gamma-ray telescope HAWC (along with earlier measurements by Milagro) indicate that these objects generate significant fluxes of very high-energy electrons. From the measured gamma-ray intensity and spectrum of these pulsars, one can calculate and constrain their expected contributions to the local cosmic-ray positron  spectrum. Among... More »
20170410 April 10, 2017, 2:00 pm Extrasolar Planets: Lessons From Kelper Yoram Lithwick, Northwestern University Astronomers have been discovering extrasolar planets at an astonishing pace.  The Kepler space telescope has discovered thousands of planets smaller than Neptune. Many of these planets’ properties were completely unexpected, based on how planets were thought to form. I will describe these surprising properties, and explain how we have inferred the densities and eccentricities of... More »
20170417 April 17, 2017, 2:00 pm The Search for Dark Photons at the SeaQuest E906 Experiment Arun Tadepalli, Rutgers The SeaQuest E906 experiment is a fixed target Drell-Yan experiment which is aimed at studying the anti-quark distributions in the nucleon and nuclei. 120 GeV protons from the Main Injector at Fermilab could also be used to search for massive dark gauge bosons or dark photons that could be generated when a proton beam dump... More »
20170424 April 24, 2017, 2:00 pm Gamma-ray Constraints on Decaying Dark Matter and Implications for IceCube Nicholas Rodd, MIT Utilizing the Fermi measurement of the gamma-ray spectrum toward the inner Galaxy, I will explain how to derive some of the strongest constraints on dark matter lifetimes in the mass range from hundreds of MeV to above an EeV.  The limits derived disfavour a decaying DM interpretation of the astrophysical neutrino flux observed by IceCube,... More »