News & Events

Kyle Cranmer
NYU

Searching for exotic Higgs decays in the LEP data

Ina Sarcevic
University of Arizona

Probing Particle Physics with Cosmic NeutrinosInteraction of cosmic rays with the microwave background radiation provides ``guaranteed'' flux of cosmic neutrinos. In addition protons accelerated in the astrophysical source interact with ambient photons and protons producing the flux of neutrinos. I will discuss how these cosmic neutrinos could be used to probe particle physics. I will show that charm production gives rise to neutrino flux from astrophysical sources with jets driven by central engine, such as gamma ray bursts or supernovae with jets. The neutrino flux from semi-leptonic decays of charmed mesons is subject to much less hadronic and radiative cooling than the conventional flux from pion and kaon decays and therefore has a dominant contribution at higher energies, of relevance to future ultrahigh energy neutrino experiments. I will briefly discuss how cosmic neutrinos can be used as probes of supersymmetry and the challenges in detecting charged staus produced in neutrino interactions. I will illustrate how neutrinos can be used as signals of dark matter annihilation in the core of the Earth or the Sun, or in halos in the universe.

Anze Slosar
Brookhaven National Lab

Probing primordial non-Gaussianity with today's universePrimordial non-Gaussianity has been traditionaly constrained using three-point function of the cosmic microwave background. Two years ago, however, Dalal et al have shown that non-Gaussianity of the local type induces a scale dependent bias for biased tracers of the underlying dark matter structure. This allows constraining of the primordial non-Gaussianity from measurements of large-scale structure provided by redshift surveys. I will discuss the technique, its theoretical aspects and current results from the real data. I will also show some preliminary new results: extension to the two field inflationary models and the analogue of the Dalal effect in the Lyman alpha forest.

David Shih
IAS

TBA

Daniel Kasen
UC Santa Cruz

The Physics of Type Ia Supernovae as Cosmological ProbesType Ia supernovae are a key element for precision cosmology missions, but the degree to which they constrain dark energy depends on how well we can calibrate them as reliable standardized candles. It is therefore important to develop a firm theoretical understanding of the physics of supernova light curves. I will explain, using both simple physical arguments and detailed numerical simulations, the origins of intrinsic luminosity variations in Type Ia supernovae and the empirical relations used to calibrate them (e.g., the Phillips relation). These theoretical studies provide a means for anticipating the potential systematic errors facing cosmology experiments, and suggest ways of obtaining more precise measurements in the future.

Aleks Diamond-Stanic
University of Arizona

Isotropic Luminosity Indicators in a Complete AGN Sample

NO HEP SEMINAR DUE TO THANKSGIVING HOLIDAY

NO ASTRO SEMINAR DUE TO THANKSGIVING HOLIDAY

Shlomo Razamat
SUNY, Stony Brook

TBA

David Law
UCLA

Tidal Disruption in a Triaxial Milky Way Dark Matter Halo: A Revised Model for the Sgr dSph GalaxyObservations of the lengthy stellar streams produced by the tidal destruction of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) can provide strong constraints on the distribution of mass within the Milky Way. However, previous work has yielded conflicting results: while the angular precession of the streams has been thought to indicate an oblate shape for the Galactic halo, the radial velocities of stars in these streams are only reproduced in prolate halo models. I demonstrate that both observational characteristics are naturally reproduced by orbits within a triaxial Milky Way dark matter halo similar to that expected from current CDM theory. I conclude by summarizing the properties of the revised Milky Way --- Sgr system and discuss the possibility of using the Sgr stream to constrain the dark sector equivalence principle.

Erick Weinberg
Columbia University

TBA

Jennifer Siegal-Gaskins
Ohio State

Using anisotropy to identify a dark matter signal in diffuse gamma-ray emission with FermiDark matter annihilation in Galactic substructure will produce diffuse gamma-ray emission of remarkably constant intensity across the sky, making it difficult to disentangle this Galactic dark matter signal from the extragalactic gamma-ray background. Recent studies have considered the angular power spectrum of the diffuse emission from various extragalactic source classes and from Galactic dark matter. I'll discuss these results and show how the energy dependence of anisotropies in the total measured diffuse emission could be used to confidently identify a signal from dark matter in Fermi data. Finally, I'll present new results demonstrating that anisotropy analysis could significantly extend the sensitivity of current indirect dark matter searches.

Christopher Herzog
Princeton University

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Gavin Salam

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Vincent Desjacques
Institute for Theoretical Physics, Zurich

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Alexander Turbiner
UNAM, Mexico

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Samson Shatashvili
Trinity College Dublin

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