Remarks on the analytic structure of supersymmetric effective actions

We study the effective superpotential of N=1 supersymmetric gauge theories with a mass gap, whose analytic properties are encoded in an algebraic curve. We propose that the degree of the curve equals the number of semiclassical branches of the gauge theory. This is true for supersymmetric QCD with one adjoint and polynomial superpotential, where the two sheets of its hyperelliptic curve correspond to the gauge theory pseudoconfining and higgs branches. We verify this proposal in the new case of supersymmetric QCD with two adjoints and superpotential V(X)+XY^2, which is the confining phase deformation of the D_{n+2} SCFT. This theory has three kinds of classical vacua and its curve is cubic. Each of the three sheets of the curve corresponds to one of the three semiclassical branches of the gauge theory. We show that one can continuously interpolate between these branches by varying the couplings along the moduli space.Comment: 49 pages, 3 figures, harvmac; typos correcte

Branched Matrix Models and the Scales of Supersymmetric Gauge Theories

In the framework of the matrix model/gauge theory correspondence, we consider supersymmetric U(N) gauge theory with $U(1)^N$ symmetry breaking pattern. Due to the presence of the Veneziano--Yankielowicz effective superpotential, in order to satisfy the $F$--term condition $\sum_iS_i=0$, we are forced to introduce additional terms in the free energy of the corresponding matrix model with respect to the usual formulation. This leads to a matrix model formulation with a cubic potential which is free of parameters and displays a branched structure. In this way we naturally solve the usual problem of the identification between dimensionful and dimensionless quantities. Furthermore, we need not introduce the $\N=1$ scale by hand in the matrix model. These facts are related to remarkable coincidences which arise at the critical point and lead to a branched bare coupling constant. The latter plays the role of the $\N=1$ and $\N=2$ scale tuning parameter. We then show that a suitable rescaling leads to the correct identification of the $\N=2$ variables. Finally, by means of the the mentioned coincidences, we provide a direct expression for the $\N=2$ prepotential, including the gravitational corrections, in terms of the free energy. This suggests that the matrix model provides a triangulation of the istanton moduli space.Comment: 1+18 pages, harvmac. Added discussion on the CSW relative shifts of theta vacua and the odd phases at the critical point. References added and typos correcte

Genetic disruption of sod1 gene causes glucose intolerance and impairs b-cell function

Oxidative stress has been associated with insulin resistance and type 2 diabetes. However, it is not clear whether oxidative damage is a cause or a consequence of the metabolic abnormalities present in diabetic subjects. The goal of this study was to determine whether inducing oxidative damage through genetic ablation of superoxide dismutase 1 (SOD1) leads to abnormalities in glucose homeostasis. We studied SOD1-null mice and wild-type (WT) littermates. Glucose tolerance was evaluated with intraperitoneal glucose tolerance tests. Peripheral and hepatic insulin sensitivity was quantitated with the euglycemic-hyperinsulinemic clamp. b-Cell function was determined with the hyperglycemic clamp and morphometric analysis of pancreatic islets. Genetic ablation of SOD1 caused glucose intolerance, which was associated with reduced in vivo b-cell insulin secretion and decreased b-cell volume. Peripheral and hepatic insulin sensitivity were not significantly altered in SOD1-null mice. High-fat diet caused glucose intolerance in WT mice but did not further worsen the glucose intolerance observed in standard chow-fed SOD1-null mice. Our findings suggest that oxidative stress per se does not play a major role in the pathogenesis of insulin resistance and demonstrate that oxidative stress caused by SOD1 ablation leads to glucose intolerance secondary to b-cell dysfunction. © 2013 by the American Diabetes Association

Updated resonance photo-decay amplitudes to 2 GeV

We present the results of an energy-dependent and set of single-energy partial-wave analyses of single-pion photoproduction data. These analyses extend from threshold to 2 GeV in the laboratory photon energy, and update our previous analyses to 1.8 GeV. Photo-decay amplitudes are extracted for the baryon resonances within this energy range. We consider two photoproduction sum rules and the contributions of two additional resonance candidates found in our most recent analysis of $\pi N$ elastic scattering data. Comparisons are made with previous analyses.Comment: Revtex, 26 pages, 3 figures. Postscript figures available from ftp://clsaid.phys.vt.edu/pub/pr or indirectly from http://clsaid.phys.vt.edu/~CAPS

Supersymmetry Breaking Vacua from M Theory Fivebranes

We consider intersecting brane configurations realizing N=2 supersymmetric gauge theories broken to N=1 by multitrace superpotentials, and softly to N=0. We analyze, in the framework of M5-brane wrapping a curve, the supersymmetric vacua and the analogs of spontaneous supersymmetry breaking and soft supersymmetry breaking in gauge theories. We show that the M5-brane does not exhibit the analog of metastable spontaneous supersymmetry breaking, and does not have non-holomorphic minimal volume curves with holomorphic boundary conditions. However, we find that any point in the N=2 moduli space can be rotated to a non-holomorphic minimal volume curve, whose boundary conditions break supersymmetry. We interpret these as the analogs of soft supersymmetry breaking vacua in the gauge theory.Comment: 32 pages, 8 figures, harvmac; v2: corrections in eq. 3.6 and in section 6, reference adde

Building the Entrepreneurial State: A New Framework for Envisioning and Evaluating a Mission-Oriented Public Sector

Today, countries around the world are seeking "smart" innovation-led growth, and hoping that this growth is also more "inclusive" and "sustainable" than in the past. This paper argues that such a feat requires rethinking the role of government and public policy in the economy - not only funding the "rate" of innovation, but also envisioning its "direction." It requires a new justification of government intervention that goes beyond the usual one of "fixing market failures." It also requires the shaping and creating of markets. And to render such growth more "inclusive," it requires attention to the ensuing distribution of "risks and rewards." To approach the innovation challenge of the future, we must redirect the discussion, away from the worry about "picking winners" and "crowding out" toward four key questions for the future: 1. Directions: how can public policy be understood in terms of setting the direction and route of change; that is, shaping and creating markets rather than just fixing them? What can be learned from the ways in which directions were set in the past, and how can we stimulate more democratic debate about such directionality? 2. Evaluation: how can an alternative conceptualization of the role of the public sector in the economy (alternative to MFT) translate into new indicators and assessment tools for evaluating public policies beyond the microeconomic cost/benefit analysis? How does this alter the crowding in/out narrative? 3. Organizational change: how should public organizations be structured so they accommodate the risk-taking and explorative capacity, and the capabilities needed to envision and manage contemporary challenges? 4. Risks and Rewards: how can this alternative conceptualization be implemented so that it frames investment tools so that they not only socialize risk, but also have the potential to socialize the rewards that enable "smart growth" to also be "inclusive growth"

Neutral Pion Photoproduction on Nuclei in Baryon Chiral Perturbation Theory

Threshold neutral pion photoproduction on light nuclei is studied in the framework of baryon chiral perturbation theory. We obtain a general formula for the electric dipole amplitude in the special case of neutral pion photoproduction on a nucleus. To third order in small momenta, the amplitude is a sum of 2- and 3-body interactions with no undetermined parameters. With reasonable input from the single nucleon sector, our result for neutral pion photoproduction on the deuteron is in agreement with experiment.Comment: 24 pages, 4 uuencoded postscript figures, uses LaTex and epsf.tex. Added footnote and references. Minor changes in text and forma

A Gauge Invariant Unitary Theory for Pion Photoproduction

A covariant, unitary and gauge invariant theory for pion photoproduction on a single nucleon is presented. To achieve gauge invariance at the operator level one needs to include both the $\pi N$ and $\gamma\pi N$ thresholds. The final amplitude can be written in terms of a distorted wave in the final $\pi N$ channel provided one includes additional diagrams to the standard Born term in which the photon is coupled to the final state pion and nucleon. These additional diagrams are required in order to satisfy gauge invariance.Comment: 4 pages, LaTeX, 1 figure as a separate uuencoded compressed tar fil