A Non-renormalization Theorem for the Wilsonian Gauge Couplings in Supersymmetric Theories

We show that the holomorphic Wilsonian beta-function of a renormalizable asymptotically free supersymmetric gauge theory with an arbitrary semi-simple gauge group, matter content, and renormalizable superpotential is exhausted at 1-loop with no higher loops and no non-perturbative contributions. This is a non-perturbative extension of the well known result of Shifman and Vainshtein.Comment: 10 pages, LaTeX; added references and clarified credit

A Consistent model of Electroweak data including Z→bb‾Z\to b\overline{b} and Z→cc‾Z\to c \overline{c}

We have performed an overall fit to the electroweak data with the generation blind $U(1)$ extension of the Standard Model. As input data for fitting we have included the asymmetry parameters, the particle decay widths of $Z$, neutrino scattering, and atomic parity violation. The QCD coupling $\alpha_s$ has been constrained to the world average obtained from all data except the $Z$ width. On the basis of our fit we have constructed a viable gauge model that not only explains $R_b$ and $R_c$ but also provides a much better overall fit to the data than the Standard Model. Despite its phenomenological viability, our model is unfortunately not simple from the theoretical viewpoint. Atomic parity violation experiments strongly disfavor more aesthetically appealing alternatives that can be grand unified.Comment: LaTexx, 14 page

Cosmology of One Extra Dimension with Localized Gravity

We examine the cosmology of the two recently proposed scenarios for a five dimensional universe with localized gravity. We find that the scenario with a non-compact fifth dimension is potentially viable, while the scenario which might solve the hierarchy problem predicts a contracting universe, leading to a variety of cosmological problems.Comment: 10 pages, LaTeX. Reference adde

Hunting Asymmetric Stops

We point out that in the irreducible natural SUSY spectrum, stops have comparable branching fractions to chargino-bottom and neutralino-top in the vast bulk of parameter space, provided only that both decay modes are kinematically accessible. The total stop pair branching fractions into ttbar + MET can therefore be reduced to O(50%), while b bbar + X branching fractions are typically much smaller, O(10%), thus limiting the reach of traditional stop searches. We propose a new stop search targeting the asymmetric final state \~t\~t* --> t chi^0 b chi^pm, which can restore sensitivity to natural stops in the 7 and 8 TeV LHC runs. In addition we present a new variable, topness, which efficiently suppresses the dominant top backgrounds to semi-leptonic top partner searches. We demonstrate the utility of topness in both our asymmetric search channel and traditional \~t\~t* --> ttbar + MET searches and show that it matches or out-performs existing variables.Comment: 5 pages, 4 figures. V2: version accepted for publication in PR

Late Inflation and the Moduli Problem of Sub-Millimeter Dimensions

We consider a recent model with sub-millimeter sized extra dimensions, where the field that determines the size of the extra dimensions (the radion) also acts as an inflaton. The radion is also a stable modulus, and its coherent oscillations can potentially overclose the Universe. It has been suggested that a second round of late inflation can solve this problem, however we find that this scenario does not allow for sufficient reheating of the Universe.Comment: 9 pages, LaTe