Regions of space time with extreme density, pressure, and curvature are important from both theoretical and observational point of view. Energy theorems predict the existence of such regions under generic conditions but say nothing about their nature. Such regions of space time if covered (black hole) are invisible to outside world. In an interesting case of a naked singularity (formed during a dust collapse) would appear to a distant observer as an expanding luminous ball. Study of observable signature of such regions (naked singularity) to a distant observer from escaping causal particles could have important physical and observational implications. (Host: Nahum Arav)

The selection of an unbiased sample of active galactic nuclei (AGN), powerful accreting supermassive black holes living in the centers of massive galaxies, is difficult. In the optical and UV, obscuration by gas and dust along our line of sight keeps us from missing all but the brightest, unobscured sources. Additional complications arise with selection in other bands (e.g., IR, radio). Using the Swift gamma-ray burst satellite, we have identified a sample of AGN in the very hard X-rays from 14-195 keV. This is the first hard X-ray survey of nearby AGN in over 30 years and expands the sample size from the previous HEAO-1 survey by hundreds of sources. This survey is particularly important because at these high energies we are selecting the true population of Compton-thin (N(H) < 10²⁴ cm-2) AGN. With this sample, we have been obtaining multi-wavelength follow-ups to better understand their properties. I will present the highlights of this survey, along with current work on the outflow properties of the Swift-selected AGN. Among our highlights, we find evidence that the trigger for AGN activity at low-redshift is through minor mergers of galaxies.

Even though flavor oscillations of elementary particles have been studied for decades, the underlying theory is still of great theoretical interest. In this talk, we will outline some of the subtleties of neutrino oscillations, such as energy-momentum conservation, coherence and localization effects, entanglement between particles, and the problem of doing QFT calculations in the flavor basis. We will illustrate some of these points using the example of Moessbauer neutrinos.

We present a novel mechanism for generating both the baryon and dark matter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the Standard Model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced non-thermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable dark matter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of dark matter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

After getting off to a slow start, CERN's Large Hadron Collider performed remarkably well in 2010 and is now on track to deliver large data samples in the coming year. In this talk, I will provide an overview of the physics results obtained thus far and will also discuss the prospects for discoveries using the data to be obtained in the next few years. Recent results to be discussed will include precision measurements of vector-boson production rates and the search for micro black holes. Prospective topics will include searches for the widely discussed Higgs boson and Supersymmetry.

In the context of GUT's in the framework of a warped extra dimension, I will review how suppressing proton decay gives a dark matter candidate as a spin-off. I will emphasize that the novel aspect of this dark matter model is that the symmetry enforcing the stability of the dark particle particle is Z₃, as opposed to Z_2i (parity) in most other models (including SUSY). Then, I will show how the two stabilization symmetries can be distinguished in collider searches for dark matter, via production of particles charged under the same symmetry, followed by their decay to SM particles and dark matter.

Searches for dark matter scattering off nuclei are typically compared assuming that the dark matter's spin-independent couplings are identical for protons and neutrons. This assumption is neither without consequence nor well motivated. We consider isospin-violating dark matter with one extra parameter, the ratio of neutron to proton couplings. For a single choice of this ratio, the DAMA and CoGeNT signals are consistent with each other and with XENON constraints, and unambiguously predict a signal at CRESST.

I will give an overview of the physics of neutrinos, particularly neutrino oscillations, with emphasis on new ideas about sensitivity to new phenomena. I will review recent experimental results on neutrino properties and their implications. I will then describe some new experimental efforts either in progress or proposed.

Cosmological observations are potentially a very sensitive probe of particle physics. In this talk I will outline what combination of observables place the tightest constraints on the sum of neutrino masses and the number of relativistic species in the early universe, and discuss what assumptions about our cosmological model these constraints depend on. The cosmological probes include the cosmic microwave background, the large-scale structure in the low-redshift universe as traced by galaxy surveys, the abundance of massive clusters, and measurements of the cosmic expansion history. I will conclude with the prospects for measuring the sum of neutrino masses cosmologically in the near future.

The matter spectrum of the MSSM, including three right-handed neutrino supermultiplets and one pair of Higgs-Higgs conjugate superfields, can be obtained by compactifying the E8 X E8 heterotic string and M-theory on Calabi-Yau manifolds with specific SU(4) vector bundles. These theories have the standard model gauge group augmented by an additional gauged U(1)_B-L. Their minimal content requires that the B-L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed sneutrino. We present the results of an explicit renormalization group analysis showing that B-L gauge symmetry is indeed radiatively broken with an appropriate B-L/electroweak hierarchy. The regions of the initial parameter space leading to realistic vacua are presented and the B-L/electroweak hierarchy computed over these regimes. At representative points, the mass spectrum for all sparticles and Higgs fields is calculated and shown to be consistent with present experimental bounds. Some fundamental phenomenological signatures of a non-zero right-handed sneutrino expectation value are discussed, particularly the proton lifetime, neutrino masses and the cosmology arising from induced lepton and baryon number violating interactions.

This talk will introduce the SNO+ experiment: a multi-purpose neutrino experiment with a broad experimental program and wide physics reach. The primary goal of SNO+ is a search for neutrinoless double beta decay, a process which has yet to be observed. A successful measurement would determine the fundamental nature of the neutrino, making it unique among fermions as being its own antiparticle, and also place limits on the absolute neutrino mass scale. SNO+ also has an extensive solar neutrino program. Although the SNO experiment unequivocally demonstrated solar neutrino oscillation, many exciting questions remain to be answered. This talk will motivate further solar neutrino studies, discuss the current status of the field, and present the potential sensitivity of SNO+.

The recent demonstrations of oscillations in the atmospheric and solar neutrino data convincingly indicate that neutrinos do have mass. Those data however, do not tell us the absolute mass scale but only the differences of the square of the neutrino masses. Even so, we now know that at least one neutrino has a mass of about 50 meV or larger.

Studies of double beta decay rates offer hope for determining the absolute mass scale. In particular, zero-neutrino double beta decay (β β (0_ν)) can address the issues of lepton number conservation, the particle-antiparticle nature of the neutrino, and its mass. In fact, upcoming generations of β β (0_ν) experiments will be sensitive to neutrino masses in the exciting range of below 50 meV. An overview of β β (0_ν) and its relation to neutrino mass will be discussed followed by a profile of a proposed experiment: the MAJORANA project.

We derive the leading alpha' corrections to the Kahler potential for the moduli in heterotic (0,2) compactifications. We show that these corrections, together with tree level and non-perturbative superpotentials, can lead to the stabilization of the volume modulus at large values, in the vein of the large volume scenarios for type IIB orientifolds. This is rather nontrivial, since our quantum corrections are of a lower order than those used in the type IIB case.

We present some recent results in obtaining the exact MSSM spectrum as well as reasonable interactions from compactification of heterotic string theory on Calabi-Yau manifolds endowed with vector bundles. We shall emphasize the method of attack, namely sifting through large classes of potentially viable geometries using the state of art developments in algebraic geometry and computer algebra. We will discuss how despite a seeming landscape, models with exact MSSM properties are quite rare.