Lepton Flavour Violating Decays of Supersymmetric Higgs Bosons

We compute the lepton flavour violating couplings of Higgs bosons in the Minimal Supersymmetric Standard Model, and show that they can induce the decays (h,H,A) --> mu tau at non-negligible rates, for large tan(beta) and sizeable smuon-stau mixing. We also discuss the prospects for detecting such decays at LHC and other colliders, as well as the correlation with other flavour violating processes, such as tau --> mu gamma and tau --> 3 mu.Comment: 13 LaTeX pages, 2 postscript figures, uses epsfig and axodra

Endogenous Market Structures and Labor Market Dynamics

We propose a flexible prices model where endogenous market structures and search and matching frictions in the labor market interact endogenously. The interplay between firms endogenous entry, strategic interactions among producers and labor market frictions represents a strong amplification channel of technology shocks on labor market variables, and helps addressing the unemployment-volatility puzzle. Consistently with U.S. evidence, new firms create a large fraction of new jobs and grow faster than more mature firms, net firms' entry is procyclical and the price mark up is countercyclical.Endogenous Market Structures; Firms' Entry; Search and Matching Frictions

Endogenous Market Structures and Labor Market Dynamics (New version)

We propose a model characterized by strategic interactions among an endogenous number of producers and search and matching frictions in the labor market. In line with U.S. data: (i) new firms account for a relatively small share of overall employment, but they create a relevant fraction of new jobs; (ii) firms’ entry is procyclical; (iii) price mark ups are countercyclical, while aggregate profits are procyclical. In response to a technology shock the labor share decreases on impact and overshoots its long run level. Also the propagation on labor market variables is stronger than in the standard search model. We argue that the countercyclicality of the price mark up is the key mechanism for our results.Endogenous Market Structures, Job Creation, Firms’ Entry, Search and Matching Frictions.

Endogenous Market Structures and Labor Market Dynamics

We propose a flexible prices model where endogenous market structures and search and matching frictions in the labor market interact endogenously. The interplay between firms endogenous entry, strategic interactions among producers and labor market frictions represents a strong amplification channel of technology shocks on labor market variables, and helps addressing the unemployment-volatility puzzle. Consistently with U.S. evidence, new firms create a large fraction of new jobs and grow faster than more mature firms, net firms’ entry is procyclical and the price mark up is countercyclical.Endogenous Market Structures, Firms’ Entry, Search and Matching Frictions

The effect on Fisher-KPP propagation in a cylinder with fast diffusion on the boundary

In this paper we consider a reaction-diffusion equation of Fisher-KPP type inside an infinite cylindrical domain in $\mathbb{R}^{N+1}$, coupled with a reaction-diffusion equation on the boundary of the domain, where potentially fast diffusion is allowed. We will study the existence of an asymptotic speed of propagation for solutions of the Cauchy problem associated with such system, as well as the dependence of this speed on the diffusivity at the boundary and the amplitude of the cylinder. When $N=1$ the domain reduces to a strip between two straight lines. This models the effect of two roads with fast diffusion on a strip-shaped field bounded by them.Comment: 31 pages, 3 figure