Measuring Dark Matter at Colliders

We investigate the need and prospects for measuring dark matter properties at particle collider experiments. We discuss the connections between the inferred properties of particle dark matter and the physics that is expected to be uncovered by the Large Hadron Collider (LHC) and the International Linear Collider (ILC) and motivate the necessity of measuring detailed dark matter properties at a collider. We then investigate a model-independent signature of dark matter at a collider and discuss its observability. We next examine the prospects for making precise measurements of dark matter properties using two example points in minimal supergravity (mSUGRA) parameter space. One of the primary difficulties encountered in such measurements is lack of constraint on the masses of unobservable heavy states. We discuss a new method for experimentally deriving estimates for such heavy masses and then conclude.Comment: 8 pages, 8 figures; Plenary talk given at PASCOS 05, Gyeongju, Republic of Korea, June 200

rSUGRA: Putting Nonuniversal Gaugino Masses on the (W)MAP

In this talk, we investigate the relic density and direct detection prospects of rSUGRA, a simple paradigm for supersymmetry breaking that allows for nonuniversal gaugino masses. We present updated plots reflecting the latest cosmological measurements from WMAP.Comment: 5 pages, 3 figures. Talk given at SUGRA 20 Conference, Northeastern University, Boston, Massachusetts, 17-21 March 200

Phenomenology of Higgsless Models at the LHC and the ILC

We investigate the signatures of the recently proposed Higgsless models at future colliders. We focus on tests of the mechanism of partial unitarity restoration in the longitudinal vector boson scattering, which do not depend on any Higgsless model-building details. We study the LHC discovery reach for charged massive vector boson resonances and show that all of the preferred parameter space will be probed with $100 {\rm fb}^{-1}$ of LHC data. We also discuss the prospects for experimental verification of the Higgsless nature of the model at the LHC. In addition, in this talk we present new results relevant for the discovery potential of Higgsless models at the International Linear Collider (ILC).Comment: 6 pages, 6 figures, to appear in the proceedings of the 2005 International Linear Collider Workshop, Stanford, US

SUSY dark matter with non-universal gaugino masses

In this talk we investigate the dark matter prospects for supersymmetric models with non-universal gaugino masses. We motivate the use of non-universal gaugino masses from several directions, including problems with the current favorite scenario, the cMSSM. We then display new corridors of parameter space that allow an acceptable dark matter relic density once gaugino mass universality is relaxed. We finish with a specific string-derived model that allows this universality relaxation and then use the dark matter constraint to make specific statements about the hidden sector of the model.Comment: Talk at Dark Matter 2002. 5 pages, 4 figure

Dark Matter at Colliders: a Model-Independent Approach

Assuming that cosmological dark matter consists of weakly interacting massive particles, we use the recent precise measurement of cosmological parameters to predict the guaranteed rates of production of such particles in association with photons at electron-positron colliders. Our approach is based on general physical principles such as detailed balancing and soft/collinear factorization. It leads to predictions that are valid across a broad range of models containing WIMPs, including supersymmetry, universal extra dimensions, and many others. We also discuss the discovery prospects for the predicted experimental signatures.Comment: 5 pages, 3 figure

Scalar Dark Matter From Theory Space

The scalar dark matter candidate in a prototypical theory space little Higgs model is investigated. We review all details of the model pertinent to dark matter. We perform a thermal relic density calculation including couplings to the gauge and Higgs sectors of the model. We find two regions of parameter space that give acceptable dark matter abundances. The first region has a dark matter candidate with a mass of order 100 GeV, the second region has a heavy candidate with a mass greater than about 500 GeV$. The dark matter candidate in either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby constituting a WIMP (weakly interacting massive particle).Comment: 18 pages, 2 figures, version to appear in PR

Mapping the 3D orientation of nanocrystals and nanostructures in human bone: Indications of novel structural features

Bone is built from collagen fibrils and biomineral nanoparticles. In humans, they are organized in lamellar twisting patterns on the microscale. It has been a central tenet that the biomineral nanoparticles are co-aligned with the bone nanostructure. Here, we reconstruct the three-dimensional orientation in human lamellar bone of both the nanoscale features and the biomineral crystal lattice from small-angle x-ray scattering and wide-angle x-ray scattering, respectively. While most of the investigated regions show well-aligned nanostructure and crystal structure, consistent with current bone models, we report a localized difference in orientation distribution between the nanostructure and the biomineral crystals in specific bands. Our results show a robust and systematic, but localized, variation in the alignment of the two signals, which can be interpreted as either an additional mineral fraction in bone, a preferentially aligned extrafibrillar fraction, or the result of transverse stacking of mineral particles over several fibrils