High Energy Physics

I will review the published quasar absorption line constraints on variations in the fine-structure constant, alpha, focusing on the apparent disagreement between those derived from Keck/HIRES and VLT/UVES spectra which have provided evidence for and against alpha variation, respectively. I demonstrate simple yet fundamental flaws in the UVES constraints which preclude reliable comparison with those from HIRES. I will outline our program to obtain a definitive UVES measurement. I will also present several new absorption line constraints on variations in the proton-to-electron mass ratio, mu. For the two molecular hydrogen absorbers from which previous authors found tentative evidence for mu-variation, we find robustly null results. A further two molecular hydrogen absorbers, including an entirely new system, also yield tight, null constraints. Finally, I present new, detailed comparison of a radio absorption system containing ammonia inversion and molecular rotational transitions which yields the strongest current astrophysical constraint on mu-variation, dmu/mu=[mu(z)-mu(lab)]/mu(lab)=[+0.74+/-0.47(stat)+/-0.76(sys)]x10^-6, at redshift z=0.685.

We discuss recent developments in the study of black holes and similar compact objects in string theory. The focus is on how these solutions are effected by higher-derivative terms in an effective action. The setting of this investigation is an off-shell formulation of five-dimensional supergravity, including terms of order four-derivatives whose precise form are determined by embedding this theory in M-theory. We find that certain singular solutions are fully regularized by the higher-derivative terms and that generic solutions receive calculable corrections to the entropy, or other relevant quantities such as the dual central charge. A particular solution studied corresponds to the geometry sourced by a fundamental string and may set the stage for a new and exciting example of holography.

Lattice QCD in this decade has succeeded in producing essential results for crucial components of Standard Model phenomenology such as constraints on the rho-eta plane. Much more will be required of lattice gauge theory in the LHC era: sub-per cent precision in QCD quantities and the ability to calculate in strongly interacting sectors of Beyond-the-Standard-Model theories such as SUSY or technicolor. I will review the status of current calculations and the prospects for accomplishing what needs to be done in the coming years.

The Higgs boson is the only scalar particle in the Standard Model. Precision electroweak analyses suggest that it should be light -- less than 200 GeV. These facts combined with the speculative nature of all electroweak symmetry breaking discussions imply significant uncertainty in discovering a Higgs boson. I discuss the unique aspects of a Higgs sector, highlight the New Physics origins of uncertainty for its phenomenology, and suggest a broader framework with which to approach Higgs boson phenomenology at the LHC.

The smaller Dark Matter structures predicted in the CDM scenario have a mass in the range [10e-12;10e-4] Msun, depending on the underlying particle physics. It is however not clear what is the inner DM structure of such halos, nor which is the real survival probability during mergers. We show how these open questions result in a large uncertainty in the prediction of the observability of such halos with indirect detection tecniques. We show predictions for the observability of the dwarf galaxies using dark matter density profiles derived from the available data on velocity dispersion curves.

We formulate non-anticommutative supersymmetry in two dimensions using differential operators acting on the component fields. We then use these operators to give a compact expression for the one-loop divergences in the non-anticommutative Kahler sigma model.