Light composite Higgs boson from the normalized Bethe-Salpeter equation

Scalar composite boson masses have been computed in QCD and Technicolor theories with the help of the homogeneous Bethe-Salpeter equation (BSE), resulting in a scalar mass that is twice the dynamically generated fermion or technifermion mass ($m_{dyn}$). We show that in the case of walking (or quasi-conformal) technicolor theories, where the $m_{dyn}$ behavior with the momenta may be quite different from the one predicted by the standard operator product expansion, this result is incomplete and we must consider the effect of the normalization condition of the BSE to determine the scalar masses. We compute the composite Higgs boson mass for several groups with technifermions in the fundamental and higher dimensional representations and comment about the experimental constraints on these theories, which indicate that models based on walking theories with fermions in the fundamental representation may, within the limitations of our approach, have masses quite near the actual direct exclusion limit.Comment: 9 pages, 4 figures, minor corrections, to appear in Physical Review

Relating a gluon mass scale to an infrared fixed point in pure gauge QCD

We show that in pure gauge QCD (or any pure non-Abelian gauge theory) the condition for the existence of a global minimum of energy with a gluon (gauge boson) mass scale also implies the existence of a fixed point of the $\beta$ function. We argue that the frozen value of the coupling constant found in some solutions of the Schwinger-Dyson equations of QCD can be related to this fixed point. We also discuss how the inclusion of fermions modifies this property.Comment: 4 pages, Revtex - Added some clarifying comments and new reference

A Survey on Security Threats and Countermeasures in IEEE Test Standards

International audienceEditor's note: Test infrastructure has been shown to be a portal for hackers. This article reviews the threats and countermeasures for IEEE test infrastructure standards

Revisiting the Random Subset Sum Problem

International audienceThe average properties of the well-known Subset Sum Problem can be studied by the means of its randomised version, where we are given a target value $z$, random variables $X_1, \ldots, X_n$, and an error parameter $\varepsilon > 0$, and we seek a subset of the $X_i$'s whose sum approximates $z$ up to error $\varepsilon$.In this setup, it has been shown that, under mild assumptions on the distribution of the random variables, a sample of size $\mathcal{O}\left(\log (1/\varepsilon)\right)$ suffices to obtain, with high probability, approximations for all values in $[-1/2, 1/2]$. Recently, this result has been rediscovered outside the algorithms community, enabling meaningful progress in other fields. In this work we present an alternative proof for this theorem, with a more direct approach and resourcing to more elementary tools, in the hope of disseminating it even further

Fixed points and vacuum energy of dynamically broken gauge theories

We show that if a gauge theory with dynamical symmetry breaking has non-trivial fixed points, they will correspond to extrema of the vacuum energy. This relationship provides a different method to determine fixed points.Comment: 17 pages, uuencoded latex file, 3 figures, uses epsf and epsfig. Submitted to Mod. Phys. Lett.

Infrared finite solutions for the gluon propagator and the QCD vacuum energy

Nonperturbative infrared finite solutions for the gluon polarization tensor have been found, and the possibility that gluons may have a dynamically generated mass is supported by recent Monte Carlo simulation on the lattice. These solutions differ among themselves, due to different approximations performed when solving the Schwinger-Dyson equations for the gluon polarization tensor. Only approximations that minimize energy are meaningful, and, according to this, we compute an effective potential for composite operators as a function of these solutions in order to distinguish which one is selected by the vacuum.Comment: 16 pages, latex file, 1 postscript figure, uses epsf.sty and axodraw.sty. To be published in Phys. Lett.

Application of a byproduct of guava processing in an Ultisol, in the presence and absence of mineral fertilization.

Abstract: There is a relative lack of technical studies on the adequate management of organic wastes from food processing. The aim of this study was to evaluate the effect of applying doses of a byproduct from guava processing, in the presence and absence of mineral fertilization, on the fertility of a an Ultisol (or Red-Yellow Argisol) under laboratory conditions. An entirely randomized 5x2 factorial experimental design was used with five byproduct doses, in the presence and absence of mineral fertilization, with four repetitions, for a total of 40 experimental units. Under the experimental conditions, the attributes pH, OM, K, Mg, BS, T, V, B, Fe, Zn and S-SO4 2? were affected by the guava byproduct doses, as well as by the presence or absence of mineral fertilization. With the use of this fertilization, the variables OM, K, H+Al, T, Fe and Zn increased more as a function of byproduct dose than in the absence of fertilization. The results obtained demonstrate the potential of using this waste material in the cycling and supply of nutrients. [Aplicación de un subproducto del procesamiento de guayaba en un Ultisol, en presencia y en ausencia de fertilización mineral]. Resumen: Hay una relativa falta de estudios técnicos sobre el manejo adecuado de los residuos orgánicos de elaboración de alimentos. El objetivo de este estudio fue evaluar el efecto de la aplicación de dosis de un subproducto del procesamiento de guayaba, en presencia y en ausencia de fertilización mineral, sobre la fertilidad de un Ultisol en condiciones de laboratorio. El diseño de experimento utilizado en este estudio fue un factorial de 5 x 2, con cinco dosis de subproductos, en presencia y en ausencia de fertilización mineral, con cuatro repeticiones, para un total de 40 unidades experimentales. En las condiciones experimentales, los atributos de pH, MO, K, Mg, SB, T, V, B, Fe, Zn y S-SO4 2? se vieron afectados por las dosis de subproducto de guayaba, así como por la presencia o ausencia de fertilización mineral. Con el uso de fertilización mineral, las variables MO, K, H + Al, T, Fe y Zn aumentaron más que en función de la dosis subproducto en ausencia de fertilización. Los resultados obtenidos demuestran el potencial del uso de este material en el ciclo y el suministro de nutrientes