Search for Higgs bosons decaying to aa in the �������� final state in pp collisions at s���= 8 TeV with the ATLAS experiment

A search for the decay to a pair of new particles of either the 125 GeV Higgs boson (h) or a second CP-even Higgs boson (H) is presented. The dataset correspods to an integrated luminosity of 20.3 fb���1 of pp collisions at s���= 8 TeV recorded by the ATLAS experiment at the LHC in 2012. The search was done in the context of the next-to-minimal supersymmetric standard model, in which the new particles are the lightest neutral pseudoscalar Higgs bosons (a). One of the two a bosons is required to decay to two muons while the other is required to decay to two ��-leptons. No significant excess is observed above the expected backgrounds in the dimuon invariant mass range from 3.7 GeV to 50 GeV. Upper limits are placed on the production of h���aa relative to the Standard Model gg���h production, assuming no coupling of the a boson to quarks. The most stringent limit is placed at 3.5% for ma= 3.75 GeV. Upper limits are also placed on the production cross section of H���aa from 2.33 pb to 0.72 pb, for fixed ma = 5 GeV with mH ranging from 100 GeV to 500 GeV.

Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at s��� = 8 TeV with the ATLAS detector

A search for the production of single-top-quarks in association with missing energy is performed in proton--proton collisions at a centre-of-mass energy of s��� = 8 TeV with the ATLAS experiment at the Large Hadron Collider using data collected in 2012, corresponding to an integrated luminosity of 20.3 fb���1. In this search, the W boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the Standard Model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-0 resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at 95% confidence level for the top quark and an invisible spin-1/2 state with mass between 0 GeV and 100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded at 95% confidence level for the top quark and an invisible spin-1 state with mass between 0 GeV and 657 GeV.

A search for t(t)over-bar resonances using lepton-plus-jets events in proton-proton collisions at root s=8 TeV with the ATLAS detector

A search for new particles that decay into top quark pairs is reported. The search is performed with the ATLAS experiment at the LHC using an integrated luminosity of 20.3 fb���1 of proton-proton collision data collected at a centre-of-mass energy of s���=8 TeV. The lepton-plus-jets final state is used, where the top pair decays to W+bW���b����, with one W boson decaying leptonically and the other hadronically. The invariant mass spectrum of top quark pairs is examined for local excesses or deficits that are inconsistent with the Standard Model predictions. No evidence for a top quark pair resonance is found, and 95% confidence-level limits on the production rate are determined for massive states in benchmark models. The upper limits on the cross-section times branching ratio of a narrow Z��� boson decaying to top pairs range from 4.2 pb to 0.03 pb for resonance masses from 0.4 TeV to 3.0 TeV. A narrow leptophobic topcolour Z��� boson with mass below 1.8 TeV is excluded. Upper limits are set on the cross-section times branching ratio for a broad colour-octet resonance with ��/m = 15% decaying to tt��. These range from 4.8 pb to 0.03 pb for masses from 0.4 TeV to 3.0 TeV. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.2 TeV.

Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at root s=8 TeV using the ATLAS experiment

Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as R-hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns to 30 ns. A search for such particles with the ATLAS detector at the Large Hadron Collider is presented, based on a data sample corresponding to an integrated luminosity of 18.4 fb���1 of pp collisions at s��� = 8 TeV. No significant deviation from the Standard Model background expectation is observed, and lifetime-dependent upper limits on R-hadrons and chargino production are set. Gluino R-hadrons with 10 ns lifetime and masses up to 1185 GeV are excluded at 95% confidence level, and so are charginos with 15 ns lifetime and masses up to 482 GeV.

Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at s =8TeV with the ATLAS detector

Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at s��� = 8 TeV corresponding to an integrated luminosity of 20.3 fb���1 collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

Relat��rio de atividade profissional

Relat��rio de atividade profissional de mestrado em Ci��ncias ��� Forma����o Cont��nua de Professores (��rea de especializa����o em F��sica e Qu��mica)

Comprensi��n en resoluci��n de problemas en F��sica: niveles de representaci��n e inferencias basadas en el conocimiento. Comprehension in Physics Problem-Solving: levels of representation and knowledge-based inferences.

Se propone desarrollar e integrar estudios sobre Modelado y Resoluci��n de Problemas en F��sica que asumen como factores explicativos: caracter��sticas de la situaci��n planteada, conocimiento de la persona que resuelve y proceso puesto en juego durante la resoluci��n. Interesa comprender c��mo los estudiantes acceden al conocimiento previo, qu�� procedimientos usan para recuperar algunos conocimientos y desechar otros, cu��les son los criterios que dan coherencia a sus decisiones, c��mo se relacionan estas decisiones con algunas caracter��sticas de la tarea, entre otras. Todo ello con miras a estudiar relaciones causales entre las dificultades encontradas y el retraso o abandono en las carreras.Se propone organizar el trabajo en tres ejes, los dos primeros de construcci��n te��rica y un tercero de implementaci��n y transferencia. Se pretende.1.-Estudiar los procesos de construcci��n de las representaciones mentales en resoluci��n de problemas de f��sica, tanto en expertos como en estudiantes de diferentes niveles acad��micos.2.-Analizar y clasificar las inferencias que se producen durante las tareas de comprensi��n en resoluci��n de problemas de f��sica. Asociar dichas inferencias con procesos de transici��n entre representaciones mentales de diferente naturaleza.3.-Desarrollar materiales y dise��os instruccionales en la ense��anza de la F��sica, fundamentado en un conocimiento de los requerimientos psicol��gicos de los estudiantes en diversas tareas de aprendizaje.En t��rminos generales se plantea un enfoque interpretativo a la luz de marcos de la psicolog��a cognitiva y de los desarrollos propios del grupo. Se trabajar�� con muestras intencionales de alumnos y profesores de f��sica. Se utilizar��n protocolos verbales y registros escritos producidos durante la ejecuci��n de las tareas con el fin de identificar indicadores de comprensi��n, inferencias, y diferentes niveles de representaci��n. Se prev�� analizar material escrito de circulaci��n corriente sea comercial o preparado por los docentes de las carreras involucradas.Las caracter��sticas del objeto de estudio y el distinto nivel de desarrollo en que se encuentran los diferentes ojetivos espec��ficos llevan a que el abordaje contemple -seg��n consideracion de Juni y Urbano (2006)- tanto la l��gica cualitativa como la cuantitativa.

Desarrollo de sistemas nano/micro-particulados con aplicaci��n en la fotodegradaci��n selectiva de contaminantes org��nicos en soluci��n. Development of nano / micro-particles systems with application to selective photodegradation of organic pollutants in solution.

IDENTIFICACI��N DEL PROBLEMA DE ESTUDIO. Las sustancias org��nicas solubles en agua no biodegradables tales como ciertos herbicidas, colorantes industriales y metabolitos de f��rmacos de uso masivo son una de las principales fuentes de contaminaci��n en aguas subterr��neas de zonas agr��colas y en efluentes industriales y dom��sticos. Las reacciones fotocatalizadas por irradiaci��n UV-visible y sensitizadores org��nicos e inorg��nicos son uno de los m��todos m��s econ��micos y convenientes para la descomposici��n de contaminantes en subproductos inocuos y/o biodegradables. En muchas aplicaciones es deseable un alto grado de especificidad, efectividad y velocidad de degradaci��n de un dado agente contaminante que se encuentra presente en una mezcla compleja de sustancias org��nicas en soluci��n. En particular son altamente deseables sistemas nano/micro -particulados que formen suspensiones acuosas estables debido a que estas permiten una f��cil aplicaci��n y una eficaz acci��n descontaminante en grandes vol��menes de fluidos. HIP��TESIS Y PLANTEO DE LOS OBJETIVOS. El objetivo general de este proyecto es desarrollar sistemas nano/micro particulados formados por pol��meros de impresi��n molecular (PIMs) y foto-sensibilizadores (FS). Un PIMs es un pol��mero especialmente sintetizado para que sea capaz de reconocer espec��ficamente un analito (mol��cula plantilla) determinado. La actividad de uni��n espec��fica de los PIMs en conjunto con la capacidad fotocatalizadora de los sensibilizadores pueden ser usadas para lograr la fotodescomposici��n espec��fica de mol��culas ���plantilla��� (en este caso un dado contaminante) en soluciones conteniendo mezclas complejas de sustancias org��nicas. MATERIALES Y M��TODOS A UTILIZAR. Se utilizaran t��cnicas de polimerizaci��n en mini-emulsi��n para sintetizar los sistemas nano/micro PIM-FS para buscar la degradaci��n de ciertos compuestos de inter��s. Para caracterizar eficiencias, mecanismos y especificidad de foto-degradaci��n en dichos sistemas se utilizan diversas t��cnicas espectrosc��picas (estacionarias y resueltas en el tiempo) y de cromatograf��a (HPLC y GC). As�� mismo, para medir directamente distribuciones de afinidades de uni��n y eficiencia de foto-degradaci��n se utilizaran t��cnicas de fluorescencia de mol��cula/part��cula individual. Estas determinaciones permitir��n obtener resultados importantes al momento de analizar los factores que afectan la eficiencia de foto-degradaci��n (nano/micro escala), tales como cantidad y ubicaci��n de foto- sensibilizadores en las matrices polim��ricas y eficiencia de uni��n de la plantilla y los productos de degradaci��n al PIM. RESULTADOS ESPERADOS. Los estudios propuestos apuntan a un mejor entendimiento de procesos foto-iniciados en entornos nano/micro-particulados para aplicar dichos conocimientos al dise��o de sistemas optimizados para la foto-destrucci��n selectiva de contaminantes acuosos de relevancia social; tales como herbicidas, residuos industriales, metabolitos de f��rmacos de uso masivo, etc. IMPORTANCIA DEL PROYECTO. Los sistemas nano/micro-particulados PIM-FS que se propone desarrollar en este proyecto se presentan como candidatos ideales para tratamientos espec��ficos de efluentes industriales y dom��sticos en los cuales se desea lograr la degradaci��n selectiva de compuestos org��nicos. Los conocimientos adquiridos ser��n indispensables para construir una plataforma vers��til de sistemas foto-catal��ticos espec��ficos para la degradaci��n de diversos contaminantes org��nicos de inter��s social. En lo referente a la formaci��n de recursos humanos, el proyecto propuesto contribuir�� en forma directa a la formaci��n de 3 estudiantes de postgrado y 2 estudiantes de grado. En las capacidades institucionales se contribuir�� al acondicionamiento del Laboratorio para Microscop��a ��ptica Avanzada (LMOA) en el Dpto. de Qu��mica de la UNRC y al montaje de un sistema de microscopio de fluorescencia que permitir�� la aplicaci��n de t��cnicas avanzadas de espectroscopia de fluorescencia de molecula individual. Water-soluble organic molecules such as certain non-biodegradable herbicides, industrial dyes and metabolites of widespread use drugs are a major source of pollution in groundwater from agricultural areas and in industrial and domestic effluents. Photo-catalytic reactions by UV-visible irradiation and organic sensitizers are one of the most economical and convenient methods for the decomposition of pollutants into harmless byproducts. In many applications it is highly desirable a high degree of specificity, effectiveness and speed of degradation of specific pollutants present in a complex mixture. In particular nano/micro-particles systems that form stable aqueous suspensions are highly desirable because they allow for easy application and effective decontamination of large volumes of fluids. Herein we propose the development of nano/micro particles composed by molecularly imprinted polymers (MIP) and photo-sensitizers (PS). The specific binding of MIP and the photo-catalytic ability of the sensitizers are used to achieve the photo-decomposition of specific "template" molecules in complex mixtures. Mini-emulsion polymerization techniques will be used to synthesize nano/micro MIP-FS systems. Spectroscopy (steady-state and time resolved) and chromatography (GC and HPLC) will be used to characterize efficiency, mechanisms and specificity of photo-degradation in these systems. In addition single molecule/particle fluorescence spectroscopy techniques will be used to directly measure distributions of binding affinities and photo-degradation efficiency in individual particles. The proposed studies point to a more detailed understanding of the factors affecting the photo-degradation efficiency in nano/micro-particles and to apply that knowledge in the design of optimized systems for photo-selective destruction of socially relevant aqueous pollutants.

Thermal process simulation of reactive particles on moving grates

Moving grate, LEPOL, Particle, Limestone, Decomposition, Clinker, Fluidisation

out-flowing behavior of particles at the discharge end of rotary kilns

Magdeburg, Univ., Fak. f��r Verfahrens- und Systemtechnik, Diss., 2009

Nasal immunization of mice with human papillomavirus type 16 virus-like particles elicits neutralizing antibodies in mucosal secretions.

To specifically induce a mucosal antibody response to purified human papillomavirus type 16 (HPV16) virus-like particles (VLP), we immunized female BALB/c mice orally, intranasally, and/or parenterally and evaluated cholera toxin (CT) as a mucosal adjuvant. Anti-HPV16 VLP immunoglobulin G (IgG) and IgA titers in serum, saliva, and genital secretions were measured by enzyme-linked immunosorbent assay (ELISA). Systemic immunizations alone induced HPV16 VLP-specific IgG in serum and, to a lesser extent, in genital secretions but no secretory IgA. Oral immunization, even in the presence of CT, was inefficient. However, three nasal immunizations with 5 microgram of VLP given at weekly intervals to anesthetized mice induced high (>10(4)) and long-lasting (>15 weeks) titers of anti-HPV16 VLP antibodies in all samples, including IgA and IgG in saliva and genital secretions. CT enhanced the VLP-specific antibody response 10-fold in serum and to a lesser extent in saliva and genital secretions. Nasal immunization of conscious mice compared to anesthetized mice was inefficient and correlated with the absence of uptake of a marker into the lung. However, a 1-microgram VLP systemic priming followed by two 5-microgram VLP intranasal boosts in conscious mice induced both HPV16 VLP-specific IgG and IgA in secretions, although the titers were lower than in anesthetized mice given three intranasal immunizations. Antibodies in serum, saliva, and genital secretions of immunized mice were strongly neutralizing in vitro (50% neutralization with ELISA titers of 65 to 125). The mucosal and systemic/mucosal HPV16 VLP immunization protocols that induced significant titers of neutralizing IgG and secretory IgA in mucosal secretions in mice may be relevant to genital HPV VLP-based human vaccine trials.

Oxidative potential for fine/ultrafine particles in occupational situations

Introduction : The redox properties of fine/ultrafine particles as well as nanoparticles (NP) are suggested to be important to explain their biological activity and could constitute a novel and promising metric for hazard evaluation. The acellular in vitro dithiothreitol (DTT) assay allows measuring this property. Objectives : (1) to evaluate sampling requirements for fine/ultrafine particle allowing measurement of their oxidative potential (2) to apply the methodology to occupational situations where particle from combustion sources are generated. Material and method : Sampling parameters (type of filters and loaded amount) and storage duration affecting the DTT measurements were evaluated. Based on these results, a methodological approach was defined and applied in two occupational situations where diesel and other combustion particles are present (toll station in a tunnel and mechanical yard for bus reparation). Results : Teflon filters loaded with diesel particles were found more suitable for the DTT assay, due to their better chemical inertness compared to quartz filters: after storage durations larger than 150 hours, an increased reactivity toward DTT was observed only with quartz filters. Reactivity was linearly correlated to the loaded mass until about 1000 μg/filter. Different redox reactivities were determined in both working places, with the mechanical yard presenting a higher DTT consumption rate. Discussion and conclusions : These results demonstrate the feasibility of this method to determine the oxidative potential of fine/ultrafine particles in occupational situations. We propose to include this approach for hazard assessment of work places with exposure to manufactured and other NP.

Development of advanced silicon radiation detectors for high energy physics and medical imaging

The 1st chapter of this work presents the different experiments and collaborations in which I am involved during my PhD studies of Physics. Following those descriptions, the 2nd chapter is dedicated to how the radiation affects the silicon sensors, as well as some experimental measurements carried out at CERN (Geneve, Schwitzerland) and IFIC (Valencia, Spain) laboratories. Besides the previous investigation results, this chapter includes the most recent scientific papers appeared in the latest RD50 (Research & Development #50) Status Report, published in January 2007, as well as some others published this year. The 3rd and 4th are dedicated to the simulation of the electrical behavior of solid state detectors. In chapter 3 are reported the results obtained for the illumination of edgeless detectors irradiated at different fluences, in the framework of the TOSTER Collaboration. The 4th chapter reports about simulation design, simulation and fabrication of a novel 3D detector developed at CNM for ions detection in the future ITER fusion reactor. This chapter will be extended with irradiation simulations and experimental measurements in my PhD Thesis.