CP Violation in Λ\Lambda to p π−\pi^-: SM vs New Physics

I discuss CP violation in $\Lambda$ to p $\pi^-$ comparing the standard model expectations with what could happen in new physics scenarios. I point out that Fermilab experiment E871 is sensitive to some of these scenarios.Comment: 6 pages, Talk at Hyperon 99 Fermilab, and at Symmetries in Subatomic Physics, Adelaide, 200

Top and bottom tensor couplings from a color octet scalar

We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and W bosons. We use known constraints on the parameters of the model to compare the predicted size of these couplings with existing phenomenological constraints.Comment: References added, matches accepted version for publicatio

Probing Anomalous Gauge Boson Couplings at LEP

We bound anomalous gauge boson couplings using LEP data for the $Z\rightarrow {\overline f} f$ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson vertices. We find that measurements at LEP constrain the three gauge boson couplings at a level comparable to that obtainable at LEPII.Comment: Latex file with 3 uuencoded figures, 13 pg, Invited talk given by S.D. at the Joint U.S.-Polish Workshop on Physics from the Planck Scale to the Electroweak Scale, Sept 21-24, 1994, Warsaw, Poland and by G.V. at the 1er. Taller Colombiano de Fenomenologia Meeting, Aug. 16-18,199

Constraints on anomalous color dipole operators from Higgs boson production at the LHC

Physics beyond the standard model (SM) can be parameterized with an effective Lagrangian that respects the symmetries of the standard model and contains many operators of dimension six. We consider the subset of these operators that is responsible for flavor diagonal anomalous color magnetic (CMDM) and electric (CEDM) dipole couplings between quarks and gluons. Invariance of these operators under the SM implies that they contribute to Higgs boson production at the LHC and we study the corresponding constraints that can be placed on them. For the case of the top-quark we first review constraints from top-quark pair production and decay, and then compare them to what can be achieved by studying $t\bar{t}h$ production. We also constrain the corresponding couplings for $b$-quarks and light quarks by studying $pp \to b\bar{b}h$ and $pp \to hX$ respectively.Comment: 20 pages, 12 figure

MONETARY POLICY WITH LIQUIDITY FRICTIONS

This paper explores the welfare effects of a reduction in the inflation rates in an environment of incomplete markets. We built a dynamic heterogeneous agent model that features idiosyncratic risks in the labor supply and liquidity frictions. The model shows that a disinflation policy results in an income reallocation among debtors and lenders. The changes in the capital returns conveys variations in the precautionary savings and hence, an intertemporal redistribution of wealth and income. The welfare implications are develop according to the incomplete market features and the money plays a role of smoothing consumption when the agents faces income variability without state contingent insurance. The model is calibrated for the Colombian economy in such a way that disinflation episodes are replicated. Early results show that the disinflation monetary policy leads to improvements of liquidity in the economy because the money holdings are used by the agents for wealth transfer over time. This paper shows quantitative evidence in which disinflation facts are associated with increments in the average real money holdings and average consumption. In addition, the volatility of consumption is reduced as the inflation rate falls, while the volatility of money holdings increases (i.e. precautionary demand for money balance).Monetary policy, heterogeneous agents, stationary distribution

Validity of two Higgs doublet models with a scalar color octet up to a high energy scale

We have recently studied theoretical constraints on the parameters of a 2HDM augmented with a color-octet scalar. In this paper we consider the consequences of requiring the model to remain valid up to very high energy scales, such as the GUT scale. The acceptable region of parameter space is reduced when one insists on vacuum stability, perturbative unitarity and the absence of Landau poles below a given scale. As the scale to which we require the model to be valid is increased, the acceptable region of parameter space for the 2HDM sector is reduced in such a way that it approaches the alignment limit, $\cos(\beta-\alpha)\to 0$, and the masses of $H^0$, $A$ and $H^\pm$ are pushed closer to each other. The parameters of the color octet sector are also restricted to an increasingly smaller region.Comment: 16 pages, 5 figures; referenced added; typos fixe