Constraining heavy colored resonances from top-antitop quark events

Recent measurements of the top quark charge asymmetry at Tevatron disfavor the existence of flavor universal axigluons and colorons at 2 sigmas. In this letter we explore the possibility to reconcile the data with these models and use the charge asymmetry and the invariant mass distribution of top-antitop quark pair events to constrain the mass and couplings of massive color-octet gauge bosons decaying to top quarks.Comment: 4 pages, 4 figures. References added, final version to appear in Phys.Rev.

Business Cycle and Political Election Outcomes: New Evidence from The Chilean Democracy

This paper explores the influence of economic variables in Chilean presidential elections. We use a panel where the dependent variable corresponds to the share of the vote obtained by the incumbent at a municipal level in the presidential elections of 1989, 1993 and 1999. We focus on the unemployment rate and the output-gap and find that both have a significant influence on the vote. The estimations also indicate that variables such as the crime rate, the poverty rate and the political coalition of the mayor in each municipality have an influence on the vote.Political elections, business cycle, unemployment

Government Subsidies and Political Elections: Evidence for Chile

In this paper, we explore the effects of government subsidies (monetary and in-kind) in presidential elections in Chile in 1989-2000. Our dependent variable is the percentage of votes obtained by the incumbent. We use a panel with three periods (the elections of 1989, 1993 and 1999) and 228 counties. We correct for the potential simultaneity problem derived from the fact that an incumbent facing a difficult political scenario might react by increasing subsidies to improve his/her electoral performance. Our results indicate that the greater the government spending on these types of programs (measured by the percentage of the population that receives the subsidy), the higher the votes for the incumbent. When we separate monetary and in-kind subsidies, we find that only inkind subsidies are statistically significant. We estimate that to obtain an additional vote, the incumbent has to spend between US$1,680 and US$1,920 (measured in PPP) in government subsidies.Political elections, subsidies, business cycle, unemployment

Magnetic Mass in 4D AdS Gravity

We provide a fully-covariant expression for the diffeomorphic charge in 4D anti-de Sitter gravity, when the Gauss-Bonnet and Pontryagin terms are added to the action. The couplings of these topological invariants are such that the Weyl tensor and its dual appear in the on-shell variation of the action, and such that the action is stationary for asymptotic (anti) self-dual solutions in the Weyl tensor. In analogy with Euclidean electromagnetism, whenever the self-duality condition is global, both the action and the total charge are identically vanishing. Therefore, for such configurations the magnetic mass equals the Ashtekhar-Magnon-Das definition.Comment: 21 pages, no figures; one reference added; final version for PR

Unemployment Insurance in Chile: Does it Stabilize the Business Cycle?

We explore the stabilizing effects of unemployment insurance in Chile. A dynamic general equilibrium model is calibrated for the Chilean economy for the 1960-2000 period. We assume that the economy is subject to exogenous technological shocks and that a fraction of the population is liquidity constrained. Our main conclusion is that unemployment insurance has some stabilizing effect on the business cycle, especially on consumption, but that this effect is of the second order of magnitude. We also find that the larger the fraction of the population that is liquidity constrained, the more likely the program is welfare improving. Our results suggest that the objective of stabilizing the business cycle would be more efficiently achieved using alternative instruments.Unemployment insurance, business cycle

Labor Market Regulations and Productivity: Evidence from Chilean Manufacturing Plants

This paper analyzes the effect of minimum wage and labor market regulations on productivity. The main hypothesis to be tested is that an increase in the relative minimum wage could have a negative effect on total factor productivity (TFP) if there are important costs of adjustment like firing costs. Using data for the Chilean manufacturing industry for the period 1992 2005, we find that the effect of relative minimum wage is negative and significant. The quantitative effect on cumulative TFP for an industry in the 25th percentile of relative minimum wage increase was a decline of 5.3% for the period 1998-2005, but for an industry in the 75th percentile of relative minimum wage increase, the cumulative reduction in TFP was 10.2%, over the same period. We also find that the continuous reduction in unilateral trade restrictions and through free trade agreements has been productivity enhancing. This is especially true for those sectors with larger exposure to international trade.TFP, minimum wage, firing costs, slowdown

Ritorno radiativo per la misura di R: come e perche

The measurement of the pion form factor and, more generally, of the cross section for electron--positron annihilation into hadrons through the radiative return has become an important task for high luminosity colliders such as the $\Phi$- or $B$-meson factories. This quantity is crucial for predictions of the hadronic contributions to $(g-2)_\mu$, the anomalous magnetic moment of the muon, and to the running of the electromagnetic coupling. But the radiative return opens also the possibility of many other physical applications. The physics potential of this method at high luminosity meson factories is discussed and recent results are reviewed.Comment: Talk given in italian at Incontri sulla Fisica delle Alte Energie, Lecce, Italy, Apr 2003; 4 page