Constraints on the rare tau decays from mu --> e gamma in the supersymmetric see-saw model

It is now a firmly established fact that all family lepton numbers are violated in Nature. In this paper we discuss the implications of this observation for future searches for rare tau decays in the supersymmetric see-saw model. Using the two loop renormalization group evolution of the soft terms and the Yukawa couplings we show that there exists a lower bound on the rate of the rare process mu --> e gamma of the form BR(mu --> e gamma) > C BR(tau --> mu gamma) BR(tau --> e gamma), where C is a constant that depends on supersymmetric parameters. Our only assumption is the absence of cancellations among the high-energy see-saw parameters. We also discuss the implications of this bound for future searches for rare tau decays. In particular, for large regions of the mSUGRA parameter space, we show that present B-factories could discover either tau --> mu gamma or tau --> e gamma, but not both.Comment: 39 pages, 7 figures. Typos corrected, references adde

Puentes que unen y muros que separan. Fronterización, securitización y procesos de cambio en las fronteras de México y Brasil

This book makes a comparative analysis between the Brazilian borders and the Mexico-US border. It focuses on the processes of border securitization that have been implemented throughout recent decades that have impacted the capacity to cross borders and border flows, as well as the quality of life of the people and regions in the borderlands. Methodologically speaking, the information about these topics is based on bibliographic research and, particularly, ethnographic data emerging from the fieldwork conducted. The combination of these two methods produced a series of up-to-date reflections regarding the current state of the border dynamics in the north and south of the American continent. The conclusions demonstrate that an increase in border securitization and border crossing in both regions is related to a State that is increasingly restrictive and cautious about the Other.El objetivo de la obra reseñada es hacer un análisis comparativo entre las fronteras de Brasil y la de México-Estados Unidos. Se enfoca en los procesos de securitización que se han dado a lo largo de las últimas décadas y que han impactado en la capacidad de tránsito y flujo a través de dichas fronteras, y también en la calidad de vida de las personas y las regiones aledañas a estas franjas fronterizas. En términos metodológicos, la información de cada apartado se nutre de la investigación bibliográfica y, sobre todo, de datos etnográficos, los cuales son producto del trabajo de campo realizado. El resultado de esta combinación es una serie de reflexiones actualizadas con respecto al estado presente de las dinámicas fronterizas en el norte y en el sur del continente. Se llega, además, a un conjunto de conclusiones que demuestran que el incremento en la securitización y en la fronterización de ambas regiones tiene que ver con un Estado cada vez más restrictivo y cauteloso contra la otredad

Gamma-rays from Heavy Minimal Dark Matter

We consider the annihilation into gamma rays of Minimal Dark Matter candidates in the fermionic 5-plet and scalar 7-plet representations of $SU(2)_L$, taking into account both the Sommerfeld effect and the internal bremsstrahlung. Assuming the Einasto profile, we show that present measurements of the Galactic Center by the H.E.S.S. instrument exclude the 5-plet and 7-plet as the dominant form of dark matter for masses between 1 TeV and 20 TeV, in particular, the 5-plet mass leading to the observed dark matter density via thermal freeze-out. We also discuss prospects for the upcoming Cherenkov Telescope Array, which will be able to probe even heavier dark matter masses, including the scenario where the scalar 7-plet is thermally produced.Comment: 27 pages, 8 figures. Matches the version accepted for publication by JCA