Last updated:03/29/11

Abstract:

In supersymmetry, the lightest Higgs scalar boson mass can be significantly increased if there are extra vector-like quarks and leptons. I will describe the motivations and phenomenology of these models. The impact on precision electroweak corrections turns out to be moderate, even if the new quarks have large Yukawa couplings. I will also discuss the production and the decays of the lightest extra quarks and leptons, and general features of the resulting collider signatures.

Abstract:

I'll discuss some recent work in which the SUSY Higgs sector is reconsidered. Since the standard construction is phenomenologically motivated, we explore the extent to which it can be generalized without conflicting with experiment. Problems including mu/Bmu and CP are reexamined in this light.

Abstract:

I will introduce a benchmark scenario in the Next-to-Minimal Supersymmetric Standard Model which possesses novel Higgs and dark matter (DM) properties. In this scenario, there naturally co-exist three light singlet-like particles: a scalar, a pseudoscalar, and a singlino-like DM candidate, all with masses of order 0.1-10 GeV. For a certain parameter window annihilation into the light pseudoscalar and exchange of the light scalar with nucleons allow the singlino to achieve the correct relic density and a direct detection cross section (spin-independent) as large as 10^{-40} cm2 simultaneously, giving the first example in the NMSSM which can accommodate a CoGeNT/DAMA favored light dark matter candidate, without violating current experimental constraints from LEP, the Tevatron, and Upsilon- and flavor physics. In addition, new non-standard decay channel is opened for the Standard Model (SM)-like Higgs boson in this scenario, while its pair-decays to the light scalars or pseudoscalars are generically suppressed. This can dramatically change our search strategies for the SM-like and light Higgs bosons at colliders therefore.

Abstract:

A leading candidate for astrophysical dark matter (DM) is a weakly interacting massive particle (WIMP) with a mass in the range from 10 GeV to 10 TeV. The self-annihilation of these particles can generate gamma-rays with energies up to the DM particle mass in the sensitivity regime of both the Fermi Large Area Telescope and ground-based gamma-ray instruments. I will report on the results of observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) to search for the gamma-ray signature of DM annihilations. VERITAS is an array of four 12-m diameter imaging atmospheric Cherenkov telescopes that is sensitive to gamma-ray energies above 100 GeV. During the past several years, VERITAS has accumulated exposure on a variety of promising targets for DM gamma-ray emission including dwarf spheroidal galaxies of the Milky Way, local group galaxies, and globular clusters. I will discuss the implications of these measurements for the parameter space of DM particle models.

Abstract:

There is overwhelming evidence for the existence of dark matter. However its particle nature remains a mystery. The sensitivity of direct and indirect searches for dark matter are each rapidly advancing and we hope soon, through them, to shed light on the properties of dark matter as well as its distribution in our Galaxy. Indirect searches are based on the detection of secondary particles produced as part of the dark matters self-annihilation or decay. Neutrinos, though hard to detect, are ideal messengers to search in this way for dark matter. The IceCube neutrino telescope, a cubic-kilometer size ice-cherenkov detector, has recently been completed at the South Pole. It is an excellent instrument to look for dark matter. Data acquired during the 6 year construction period have been searched for evidence of dark matter annihilations in the Sun and in the Galactic center and halo, in the form of an excess neutrino flux over the predicted backgrounds from those directions. I will review the results of these searches and discuss the potential of on-going and future searches. A particular focus will be put on the low-energy extension of IceCube, Deep-Core, which is taking data since June 2010 and offers exciting opportunities for dark matter searches down to candidate masses in the physically interesting region below 100 GeV.