Reheating Metastable O'Raifeartaigh Models

In theories with multiple vacua, reheating to a temperature greater than the height of a barrier can stimulate transitions from a desirable metastable vacuum to a lower energy state. We discuss the constraints this places on various theories and demonstrate that in a class of supersymmetric models this transition does not occur even for arbitrarily high reheating temperature.Comment: 21 pages, 1 figure. Typos corrected and some references adde

A Stringy Test of Flux-Induced Isometry Gauging

Supergravity analysis suggests that the effect of fluxes in string theory compactifications is to gauge isometries of the scalar manifold. However, isometries are generically broken by brane instanton effects. Here we demonstrate how fluxes protect exactly those isometries from quantum corrections which are gauged according to the classical supergravity analysis. We also argue that all other isometries are generically broken.Comment: 14 pages, 1 figure; v2: references adde

The Benefits of Stress: Resolution of the Lifshitz Singularity

Through the AdS/CFT correspondence, Lifshitz spacetimes describe field theories with dynamical scaling ($z \neq 1$). Although curvature invariants are small, the Lifshitz metric exhibits a null singularity in the IR with a large tidal force that excites string oscillator modes. However, Lifshitz is not a vacuum solution of the Einstein equations -- the metric is supported by nontrivial matter content which must be taken into account in analyzing the propagation of test objects. In this paper, we consider the interaction of a string with a D0-brane density in the IR which supports a class of UV-complete $z=2$ Lifshitz constructions. We show that string/D-brane scattering in the Regge limit slows the string significantly, preventing divergent mode production and resolving the would-be singularity in string propagation.Comment: 16 pages; v2: new references adde

Discovering Chiral Higgsinos at the LHC

The concept of chirality is extended to the Minimal Supersymmetric Standard Model (MSSM) and the {micro} term is forbidden by a gauged U(1){prime} symmetry. R-parity automatically emerges after symmetry breaking, suppressing proton decay and protecting the LSP. Exotics charged under the SM pose a challenge to traditional SU(5) unification, but unification is still implemented in deconstructed GUTs. Because of the multitude of additional states to the MSSM, the Z{prime} has a large width, and the SM background, neglected in previous theoretical studies, becomes important for Z{prime} discovery. As a result, the LHC reach is reduced from 3.2 TeV, for a Z{prime} with SM decays, to 1.5 TeV, when additional decay channels are included. This model also predicts possibly long-lived colored and electroweak exotics

New Fixed-Target Experiments to Search for Dark Gauge Forces

Fixed-target experiments are ideally suited for discovering new MeV-GeV mass U(1) gauge bosons through their kinetic mixing with the photon. In this paper, we identify the production and decay properties of new light gauge bosons that dictate fixed-target search strategies. We summarize existing limits and suggest five new experimental approaches that we anticipate can cover most of the natural parameter space, using currently operating GeV-energy beams and well-established detection methods. Such experiments are particularly timely in light of recent terrestrial and astrophysical anomalies (PAMELA, FERMI, DAMA/LIBRA, etc.) consistent with dark matter charged under a new gauge force.Comment: 14 pages + 6 page appendix and refs, 11 figure

Comments on worldsheet theories dual to free large N gauge theories

We continue to investigate properties of the worldsheet conformal field theories (CFTs) which are conjectured to be dual to free large N gauge theories, using the mapping of Feynman diagrams to the worldsheet suggested in hep-th/0504229. The modular invariance of these CFTs is shown to be built into the formalism. We show that correlation functions in these CFTs which are localized on subspaces of the moduli space may be interpreted as delta-function distributions, and that this can be consistent with a local worldsheet description given some constraints on the operator product expansion coefficients. We illustrate these features by a detailed analysis of a specific four-point function diagram. To reliably compute this correlator we use a novel perturbation scheme which involves an expansion in the large dimension of some operators.Comment: 43 pages, 16 figures, JHEP format. v2: added reference

SUSY Simplified Models at 14, 33, and 100 TeV Proton Colliders

Results are presented for a variety of SUSY Simplified Models at the 14 TeV LHC as well as a 33 and 100 TeV proton collider. Our focus is on models whose signals are driven by colored production. We present projections of the upper limit and discovery reach in the gluino-neutralino (for both light and heavy flavor decays), squark-neutralino, and gluino-squark Simplified Model planes. Depending on the model a jets + MET, mono-jet, or same-sign di-lepton search is applied. The impact of pileup is explored. This study utilizes the Snowmass backgrounds and combined detector. Assuming 3000 fb^{-1} of integrated luminosity, a gluino that decays to light flavor quarks can be discovered below 2.3 TeV at the 14 TeV LHC and below 11 TeV at a 100 TeV machine.Comment: 81 pages, 55 figures; v2 journal versio

Testing Atom and Neutron Neutrality with Atom Interferometry

We propose an atom-interferometry experiment based on the scalar Aharonov-Bohm effect which detects an atom charge at the 10{sup -28} e level, and improves the current laboratory limits by 8 orders of magnitude. This setup independently probes neutron charges down to 10{sup 28} e, 7 orders of magnitude below current bounds

The Moduli Space and M(Atrix) Theory of 9d N=1 Backgrounds of M/String Theory

We discuss the moduli space of nine dimensional N = 1 supersymmetric compactifications of M theory/string theory with reduced rank (rank 10 or rank 2), exhibiting how all the different theories (including M theory compactified on a Klein bottle and on a Moebius strip, the Dabholkar-Park background, CHL strings and asymmetric orbifolds of type II strings on a circle) fit together, and what are the weakly coupled descriptions in different regions of the moduli space. We argue that there are two disconnected components in the moduli space of theories with rank 2. We analyze in detail the limits of the M theory compactifications on a Klein bottle and on a Moebius strip which naively give type IIA string theory with an uncharged orientifold 8-plane carrying discrete RR flux. In order to consistently describe these limits we conjecture that this orientifold non-perturbatively splits into a D8-brane and an orientifold plane of charge (-1) which sits at infinite coupling. We construct the M(atrix) theory for M theory on a Klein bottle (and the theories related to it), which is given by a 2 + 1 dimensional gauge theory with a varying gauge coupling compactified on a cylinder with specific boundary conditions. We also clarify the construction of the M(atrix) theory for backgrounds of rank 18, including the heterotic string on a circle

The Black Hole in the Throat - Thermodynamics of Strongly Coupled Cascading Gauge Theories

We numerically construct black hole solutions corresponding to the deconfined, chirally symmetric phase of strongly coupled cascading gauge theories at various temperatures. We compute the free energy as a function of the temperature, and we show that it becomes positive below some critical temperature, indicating the possibility of a first order phase transition at which the theory deconfines and restores the chiral symmetry