Fast multipole method applied to 3D frequency domain elastodynamics

This article is concerned with the formulation and implementation of a fast multipole-accelerated BEM for 3-D elastodynamics in the frequency domain, based on the so-called diagonal form for the expansion of the elastodynamic fundamental solution, a multi-level strategy. As usual with the FM-BEM, the linear system of BEM equations is solved by GMRES, and the matrix is never explicitly formed. The truncation parameter in the multipole expansion is adjusted to the level, a feature known from recent published studies for the Maxwell equations. A preconditioning strategy based on the concept of sparse approximate inverse (SPAI) is presented and implemented. The proposed formulation is assessed on numerical examples involving $O(10^{5})$ BEM unknowns, which show in particular that, as expected, the proposed FM-BEM is much faster than the traditional BEM, and that the GMRES iteration count is significantly reduced when the SPAI preconditioner is used

Fingerprints of heavy scales in electroweak effective Lagrangians

The couplings of the electroweak effective theory contain information on the heavy-mass scales which are no-longer present in the low-energy Lagrangian. We build a general effective Lagrangian, implementing the electroweak chiral symmetry breaking $SU(2)_L\otimes SU(2)_R\to SU(2)_{L+R}$, which couples the known particle fields to heavier states with bosonic quantum numbers $J^P=0^\pm$ and $1^\pm$. We consider colour-singlet heavy fields that are in singlet or triplet representations of the electroweak group. Integrating out these heavy scales, we analyze the pattern of low-energy couplings among the light fields which are generated by the massive states. We adopt a generic non-linear realization of the electroweak symmetry breaking with a singlet Higgs, without making any assumption about its possible doublet structure. Special attention is given to the different possible descriptions of massive spin-1 fields and the differences arising from naive implementations of these formalisms, showing their full equivalence once a proper short-distance behaviour is required.Comment: 57 pages, 1 pdf figure. Version published at JHE

A few words about Resonances in the Electroweak Effective Lagrangian

Contrary to a widely spread believe, we have demonstrated that strongly coupled electroweak models including both a light Higgs-like boson and massive spin-1 resonances are not in conflict with experimental constraints on the oblique S and T parameters. We use an effective Lagrangian implementing the chiral symmetry breaking SU(2)_L x SU(2)_R -> SU(2)_{L+R} that contains the Standard Model gauge bosons coupled to the electroweak Goldstones, one Higgs-like scalar state h with mass m_h=126 GeV and the lightest vector and axial-vector resonance multiplets V and A. We have considered the one-loop calculation of S and T in order to study the viability of these strongly-coupled scenarios, being short-distance constraints and dispersive relations the main ingredients of the calculation. Once we have constrained the resonance parameters, we do a first approach to the determination of the low energy constants of the electroweak effective theory at low energies (without resonances). We show this determination in the case of the purely Higgsless bosonic Lagrangian.Comment: 6 pages, 2 figures. Talk given at XIth Quark Confinement and Hadron Spectrum, 8-12th September (2014), Saint Petersburg (Russia

La minería española 2008-09

El año 2008 y los comienzos del 2009 ha sido para la minería española, al igual que muchos otros sectores de la economía española, un periodo de enorme trascendencia. La aguda crisis que vive el mundo actual ha incidido, sin embargo, de manera diferente según los sub-sectores en que se divide la industria mineral. Así, aquellos más directamente ligados al desarrollo de la construcción (áridos, piedra natural y ciertos minerales industriales) han visto derrumbarse la demanda de sus productos finales hasta extremos muy agudos. Sin embargo y a pesar de momentos de incertidumbre al finalizar el año pasado, los combustibles fósiles sólidos y los minerales metálicos, en general, se sitúan entre la esperanza y el desconocimiento de la evolución en los próximos meses. De esta manera, hay que felicitarse de disponer en este momento de cuatro minas metálicas, algunas de ellas de verdadero interés a nivel europeo

La huella del carbono en la clasificación ambiental de los proyectos mineros: Cobre Las Cruces

En los últimos tiempos existe una batería de herramientas y metodología de gestión ambiental desarrolladas por la comunidad científica dedicada a la investigación de los valores ambientales y su mejor gestión. Derivada del concepto de ACV, tambien existe la GER o energía primaria consumida en todas las etapas de ciclo de vida y que es un excelente indicador de la sostenibilidad del proceso. Además, del inventario obligado de en las categorías de impacto ambiental incluido en el ACV, se derivan los resultados o efectos acumulados del proceso en estudio, categorizados como consecuencias ambientales. Del análisis de Ciclo de Vida se deriva, de manera natural, la Huella del Carbono que no viene a ser nada más que la contabilidad de efectos ambientales derivados de el consumo de energía e emisiones de gases invernadero medidos en unidades de CO2 equivalentes. Estas últimas herramientas constituyen todas juntas una manera relativamente fácil de proceder para efectuar una clasificación de la condición de sostenibilidad de un proyecto miner

Heavy resonances and the oblique parameters S and T

It has been confirmed experimentally the existence of a mass gap between Standard Model (SM) and eventual Beyond Standard Model (BSM) fields. Therefore, the use of effective approaches to search for fingerprints of New Physics is very appealing. A non-linear realizations of the Electroweak Symmetry Breaking is considered here, where the Higgs is a singlet with free couplings and the SM fields are also coupled to bosonic heavy resonances. A one-loop-level calculation of the oblique S and T parameters is presented here. This analysis allows us to constrain resonance masses to be above the TeV scale, $M_R\!>\! 3\,$TeV, in good agreement with our previous determinations, where these observables were computed with a more simplified Lagrangian.Comment: Talk given at the 26th International Conference in Quantum Chromodynamics (QCD 23), 10-14 July 2023, Montpellier (France). 7 pages, 3 figure