GUT predictions for quark-lepton Yukawa coupling ratios with messenger masses from non-singlets

We propose new predictions from grand unified theories (GUTs) [applicable to both supersymmetric (SUSY) and non-SUSY models] for the ratios of quark and lepton Yukawa couplings. These new predictions arise from splitting the masses of the messenger fields for the GUT-scale Yukawa operators by Clebsch-Gordan factors from GUT symmetry breaking. This has the effect that these factors enter inversely in the predicted quark-lepton Yukawa coupling ratios, leading to new possible GUT predictions. We systematically construct the new predictions that can be realized in this way in SU(5) GUTs and Pati-Salam unified theories and discuss model building applications

Measuring x-ray polarization in the presence of systematic effects: Known background

The prospects for accomplishing x-ray polarization measurements of astronomical sources have grown in recent years, after a hiatus of more than 37 years. Unfortunately, accompanying this long hiatus has been some confusion over the statistical uncertainties associated with x-ray polarization measurements of these sources. We have initiated a program to perform the detailed calculations that will offer insights into the uncertainties associated with x-ray polarization measurements. Here we describe a mathematical formalism for determining the 1- and 2-parameter errors in the magnitude and position angle of x-ray (linear) polarization in the presence of a (polarized or unpolarized) background. We further review relevant statistics-including clearly distinguishing between the Minimum Detectable Polarization (MDP) and the accuracy of a polarization measurement.Comment: 12 pages, 4 figures, for SPIE conference proceeding

On understanding the figures of merit for detection and measurement of x-ray polarization

The prospects for accomplishing X-ray polarization measurements appear to have grown in recent years after a more than 35-year hiatus. Unfortunately, this long hiatus has brought with it some confusion over the statistical uncertainties associated with polarization measurements of astronomical sources. The heart of this confusion stems from a misunderstanding (or potential misunderstanding) of a standard figure of merit-the minimum detectable polarization (MDP)-that one of us introduced many years ago. We review the relevant statistics, and quantify the differences between the MDP and the uncertainty of an actual polarization measurement. We discuss the implications for future missions.Comment: 5 pages, 2 figures, to be presented at SPIE conference 7732 (paper 13), corrected typo

Methods of optimizing X-ray optical prescriptions for wide-field applications

We are working on the development of a method for optimizing wide-field X-ray telescope mirror prescriptions, including polynomial coefficients, mirror shell relative displacements, and (assuming 4 focal plane detectors) detector placement along the optical axis and detector tilt. With our methods, we hope to reduce number of Monte-Carlo ray traces required to search the multi-dimensional design parameter space, and to lessen the complexity of finding the optimum design parameters in that space. Regarding higher order polynomial terms as small perturbations of an underlying Wolter I optic design, we begin by using the results of Monte-Carlo ray traces to devise trial analytic functions, for an individual Wolter I mirror shell, that can be used to represent the spatial resolution on an arbitrary focal surface. We then introduce a notation and tools for Monte-Carlo ray tracing of a polynomial mirror shell prescription which permits the polynomial coefficients to remain symbolic. In principle, given a set of parameters defining the underlying Wolter I optics, a single set of Monte-Carlo ray traces are then sufficient to determine the polymonial coefficients through the solution of a large set of linear equations in the symbolic coefficients. We describe the present status of this development effort.Comment: 14 pages, to be presented at SPIE conference 7732 (paper 93

Implications of gauge-mediated supersymmetry breaking with vector-like quarks and a ~125 GeV Higgs boson

We investigate the implications of models that achieve a Standard Model-like Higgs boson of mass near 125 GeV by introducing additional TeV-scale supermultiplets in the vector-like 10+\bar{10} representation of SU(5), within the context of gauge-mediated supersymmetry breaking. We study the resulting mass spectrum of superpartners, comparing and contrasting to the usual gauge-mediated and CMSSM scenarios, and discuss implications for LHC supersymmetry searches. This approach implies that exotic vector-like fermions t'_{1,2}, b',and \tau' should be within the reach of the LHC. We discuss the masses, the couplings to electroweak bosons, and the decay branching ratios of the exotic fermions, with and without various unification assumptions for the mass and mixing parameters. We comment on LHC prospects for discovery of the exotic fermion states, both for decays that are prompt and non-prompt on detector-crossing time scales.Comment: 32 pages. v2: references added, figure caption 5.3 correcte

Refined gluino and squark pole masses beyond leading order

The physical pole and running masses of squarks and gluinos have recently been related at two-loop order in a mass-independent renormalization scheme. I propose a general method for improvement of such formulas, and argue that better accuracy results. The improved version gives an imaginary part of the pole mass that agrees exactly with the direct calculation of the physical width at next-to-leading order. I also find the leading three-loop contributions to the gluino pole mass in the case that squarks are heavier, using effective field theory and renormalization group methods. The efficacy of these improvements for the gluino and squarks is illustrated with numerical examples. Some necessary three-loop results for gauge coupling and fermion mass beta functions and pole masses in theories with more than one type of fermion representation, which are not directly accessible from the published literature, are presented in an Appendix.Comment: 14 pages. v2: typos in equations (A.11), (A.17), and (A.18) fixe

Radiative Inflation and Dark Energy

We propose a model based on radiative symmetry breaking that combines inflation with Dark Energy and is consistent with the WMAP 7-year regions. The radiative inflationary potential leads to the prediction of a spectral index 0.955 \lesssim n_S \lesssim 0.967 and a tensor to scalar ratio 0.142 \lesssim r \lesssim 0.186, both consistent with current data but testable by the Planck experiment. The radiative symmetry breaking close to the Planck scale gives rise to a pseudo Nambu-Goldstone boson with a gravitationally suppressed mass which can naturally play the role of a quintessence field responsible for Dark Energy. Finally, we present a possible extra dimensional scenario in which our model could be realised.Comment: 15 pages, 4 figures; v2: references added, appendix added, Section 5 slightly modified; content matches published versio