Conflict and Uncertainty: A Dynamic Approach

Most of the conflict theory papers have used a one-shot game set-up. This does not correspond to reality and is certainly incapable of modeling real conflict situations. We propose a dynamic model with N-agents in an infinite time frame which allow us to adequately analyze conflicts. The dynamic aspects of the conflict come at least from two sources: first, the preferences on the good in dispute are not static; second, agentsin conflict can influence the future of the conflict by making investment in conflict's technology. We use a simple deterministic rule that defines the evolution of the subjective valuation for the good in dispute according to the results obtained by the agents in the recent past. During each period the realization of stochastic variables of the nature's states induces uncertainty in the game. The model is a theoretical approach that can be applied to evaluate the role of uncertainty and valuations' evolution on the optimal choices of forward-looking economic agents that seek to appropriate a share of a divisible resource.Conflict Theory, Dynamic Economic Model, Uncertainty

New limits on the mass of neutral Higgses in General Models

In general electroweak models with weakly coupled (and otherwise arbitrary) Higgs sector there always exists in the spectrum a scalar state with mass controlled by the electroweak scale. A new and simple recipe to compute an analytical tree-level upper bound on the mass of this light scalar is given. We compare this new bound with similar ones existing in the literature and show how to extract extra information on heavier neutral scalars in the spectrum from the interplay of independent bounds. Production of these states at future colliders is addressed and the implications for the decoupling limit in which only one Higgs is expected to remain light are discussed.Comment: 14 pages, LaTe

On government credit programs

Credit rationing is a common feature of most developing economies. In response to it, the governments of these countries often operate extensive credit programs and lend, either directly or indirectly, to the private sector. We analyze the macroeconomic consequences of a typical government credit program in a small open economy. We show that such programs increase long-run production if the economy is in a development trap and that such programs often lead to endogenously arising aggregate volatility. On the other hand, they may eliminate certain indeterminacies created by endogenous credit market frictions.Banks and banking, Central ; Credit ; Productivity

Electroweak Breaking and the mu problem in Supergravity Models with an Additional U(1)

We consider electroweak symmetry breaking in supersymmetric models with an extra non-anomalous U(1)' gauge symmetry and an extra standard-model singlet scalar S. For appropriate charges the U(1)' forbids an elementary mu term, but an effective mu is generated by the VEV of S, leading to a natural solution to the mu problem. There are a variety of scenarios leading to acceptably small Z-Z' mixing and other phenomenological consequences, all of which involve some but not excessive fine tuning. One class, driven by a large trilinear soft supersymmetry breaking term, implies small mixing, a light Z' (e.g., 200 GeV), and an electroweak phase transition that may be first order at tree level. In another class, with m_S^2 < 0 (radiative breaking), the typical scale of dimensional parameters, including M_{Z'} and the effective mu, is O(1 TeV), but the electroweak scale is smaller due to cancellations. We relate the soft supersymmetry breaking parameters at the electroweak scale to those at the string scale, choosing Yukawa couplings as determined within a class of string models. We find that one does not obtain either scenario for universal soft supersymmetry breaking mass parameters at the string scale and no exotic multiplets contributing to the renormalization group equations. However, either scenario is possible when the assumption of universal soft breaking is relaxed. Radiative breaking can also be generated by exotics, which are expected in most string models.Comment: 45 pages, revtex, 20 eps figures, psfig.sty; Minor numerical renormalization group results corrected. Erratum to appear in Phys. Rev.

Barriers to international capital flows: when, why, how big, and for whom?

Until recently, the trend in world capital markets has been toward increasing “globalization.” Recent events in Latin America and Asia have forced a rethinking of the desirability of unrestricted world capital flows. In this paper we ask whether simple restrictions on capital mobility can succeed in reducing the volatility of funds flows, whether such restrictions are consistent with the long-term development of the countries that might impose them, whether such restrictions are beneficial for poorer countries while harming wealthier countries, and whether barriers to capital movements should be reduced in magnitude as the development process proceeds. ; We find first that appropriately selected barriers to capital movements can be used by a poorer country to eliminate the short-term volatility of capital flows and other economic volatility as well. Second, we find that these barriers are consistent with increased rather than reduced levels of economic development in both the short and long run. Third, we show that it is empirically plausible that such barriers will be reduced over time as economies develop. Fourth, we show that, in the long run, all countries can benefit from the presence of barriers to capital mobility. And, fifth, we show that barriers to capital mobility can increase the magnitude of net capital flows in a steady state.International economic relations ; International finance ; Capital movements ; Monetary policy

A Cosmological Signature of the Standard Model Higgs Vacuum Instability: Primordial Black Holes as Dark Matter

For the current central values of the Higgs and top masses, the Standard Model Higgs potential develops an instability at a scale of the order of $10^{11}$ GeV. We show that a cosmological signature of such instability could be dark matter in the form of primordial black holes seeded by Higgs fluctuations during inflation. The existence of dark matter might not require physics beyond the Standard Model.Comment: 6+1 pages, 3 figures; v2: updated to the published PRL version, and added an Appendix about Non-Gaussian effect

Socially excessive bankruptcy costs and the benefits of interest rate ceilings on loans

The authors study the capital accumulation and welfare implications of ceilings on loan interest rates in a dynamic general equilibrium model. Binding ceilings on loan rates reduce the probability of bankruptcy. Lower bankruptcy rates result in lower bankruptcy and liquidation costs. The authors state conditions under which the resources freed by this cost-saving result increase the steady state capital stock, reduce steady state credit rationing, and raise the steady state welfare of all agents. The authors also argue that the conditions stated are likely to be satisfied in practice. Finally, their results hold even if initially there is capital over-accumulation.Loans ; Interest rates ; Bankruptcy

Identities For Homogeneous Utility Functions

Using a homogeneous and continuous utility function that represents a household's preferences, this paper proves explicit identities between most of the different objects that arise from the utility maximization and the expenditure minimization problems. The paper also outlines the homogeneity properties of each object. Finally, we show explicit algebraic ways to go from the indirect utility function to the expenditure function and from the Marshallian demand to the Hicksian demand and vice versa, without the need of any other function, thus simplifying the integrability problem avoiding the use of differential equations.Identities, homogeneous utility functions and household theory.

Some Cosmological Implications of Hidden Sectors

We discuss some cosmological implications of extensions of the Standard Model with hidden sector scalars coupled to the Higgs boson. We put special emphasis on the conformal case, in which the electroweak symmetry is broken radiatively with a Higgs mass above the experimental limit. Our refined analysis of the electroweak phase transition in this kind of models strengthens the prediction of a strongly first-order phase transition as required by electroweak baryogenesis. We further study gravitational wave production and the possibility of low-scale inflation as well as a viable dark matter candidate.Comment: 23 pages, 8 figures; some comments added, published versio