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Thursday, January 18th 2007

12:15 pm:

Thursday, January 25th 2007

12:15 pm:

Thursday, February 1st 2007

12:15 pm:

Thursday, February 8th 2007

12:15 pm:

Friday, February 16th 2007

2:30 pm:

Thursday, February 22nd 2007

12:15 pm:

Thursday, March 1st 2007

12:15 pm:

Thursday, March 8th 2007

12:15 pm:

Thursday, March 15th 2007

12:15 pm:

Thursday, March 22nd 2007

12:15 pm:

Thursday, March 29th 2007

12:15 pm:

We propose a gravitational dual for ``single-sector'' models. These are supersymmetric extensions to the Standard Model where some particles of the Minimal Supersymmetric Standard Model MSSM)

are composites of a strongly-coupled gauge theory. The composite states feel supersymmetry-breaking directly. As a consequence, the spectrum of the MSSM is split: first and second generation squarks and sleptons obtain masses of order 5-10 TeV. The remaining MSSM fields experience gauge mediation. In our work, the single-sector scenario is expressed in a dual gravitational

AdS(5)-like description, inspired by flux-background solutions of Type IIB supergravity. These backgrounds have all supersymmetry broken in the depths of the ``throat,'' equivalent to the vicinity of the infrared brane. Specifically, the metric deviates from AdS(5) near the IR brane. A single parameter

characterizes the supersymmetry-breaking of the background in this MSSM-in-the-bulk model. Thus, the model is highly predictive. The collider signals are investigated and are shown

to be similar to gauge mediation with a neutralino NLSP that decays promptly to a gravitino LSP, but with rates that are lower by a factor of a few; the single-sector models can be detected and distinguished from mSUGRA and conventional gauge mediation with 1-10 1/fb of LHC data.

Thursday, April 5th 2007

12:15 pm:

Thursday, April 12th 2007

12:15 pm:

A new class of constraint system applicable to continuous covariant field theories is explained. When coupled to gravity, it modifies the constraints of Einstein equations. Cosmological implications are also presented.

Thursday, April 19th 2007

12:15 pm:

I will discuss our formalism for implementing N=1 SYM on a 3D

lattice and our plans to test a conjecture by Witten - hep-th/9903005 - that SUSY is spontaneously broken for certain values of the Chern-Simons coupling.

Thursday, April 26th 2007

12:15 pm:

Thursday, May 10th 2007

12:15 pm:

Thursday, June 14th 2007

12:15 pm:

The origin of matter in the universe from a decaying inflaton field is a basic feature of the inflationary paradigm. In many models, the first stage of this process, called preheating, is dominated by an explosive and non-perturbative production of highly inhomogeneous, non-thermal field fluctuations. These act in particular as a classical source for gravitational radiation.

In this talk, I will first review some aspects of preheating and of the subsequent evolution of the inflaton decay products towards thermal equilibrium. I will then discuss the computation of the resulting background of gravitational waves. The corresponding spectrum has a higher amplitude than the one generated during inflation, and it may fall into the range accessible for direct detection experiments (LIGO/VIRGO or BBO) if inflation occurs at a low enough energy scale. The discovery of such a background would open a new observational window into the dynamics of the very early universe.

Thursday, September 6th 2007

12:15 pm:

Thursday, September 13th 2007

12:15 pm:

Thursday, September 20th 2007

12:15 pm:

Thursday, September 27th 2007

12:15 pm:

Thursday, October 4th 2007

12:15 pm:

Thursday, October 11th 2007

12:15 pm:

Thursday, October 18th 2007

12:15 pm:

The cosmological constant problem and the compatibility of gravity with quantum mechanics are the two most pressing problems in all of gravitational theory. While string theory nicely addresses the latter, it has so far failed to provide any compelling solution to the former. On the other hand, while conformal gravity nicely addresses the cosmological constant problem (by naturally quenching the amount by which the cosmological constant gravitates rather than by quenching the cosmological constant itself), the fourth order derivative conformal theory has long been thought to possess a ghost when quantized. However, it has recently been shown by Bender and Mannheim that not only do theories based on fourth order derivative equations of motion not have ghosts, they actually never had any to begin with, with the apparent presence of ghosts being due entirely to treating operators which were not Hermitian on the real axis as though they were. When this is taken care of via an underlying PT symmetry that such theories are found to possess, there are then no ghosts at all and the S-matrix is fully unitary. Conformal gravity is thus advanced as a fully consistent four-dimensional alternative to ten-dimensional string theory.

Thursday, October 25th 2007

12:15 pm:

Thursday, November 1st 2007

12:15 pm:

Thursday, November 8th 2007

12:15 pm:

Thursday, November 15th 2007

12:15 pm:

Explaining the predominance of visible matter over antimatter

remains one of the outstanding puzzles at the interface of cosmology with particle and nuclear physics. Although the Standard Model cannot account for the matter-antimatter asymmetry, new physics at the electroweak scale may provide the solution. In this talk, I discuss the general requirements for successful electroweak scale baryogenesis; recent theoretical work in computations of the matter-antimatter asymmetry; and implications for experimental searches for permanent electric dipole moments of the electron and neutron and for the Higgs

boson at future colliders.

Thursday, November 29th 2007

12:15 pm:

Thursday, December 6th 2007

12:15 pm:

Thursday, December 13th 2007

12:15 pm:

New strong interactions at the LHC may exhibit a richer structure than a rescaled version of QCD at the electroweak scale. This departure from rescaled QCD is required to construct scenarios of strong interactions compatible with electroweak constraints. In this talk we use a simple framework, based on a 5D model with a modification of AdS geometry in the infrared, to navigate among these scenarios and propose two points with particularly interesting phenomenology. Within these benchmark points we explore the discovery of vector and axial resonances in the Drell-Yan, associated production and vector boson fusion channels.

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