Search results for "Fotones"
showing 6 items of 6 documents
Análisis de la emisión óptica y la correlación de fotones en puntos cuánticos aislados de Arseniuro de Indio
2014
En la presente tesis se han realizado un conjunto de investigaciones experimentales en el marco de la micro-espectroscopia óptica como base para el estudio de las propiedades ópticas y la dinámica de recombinación excitónica en puntos cuánticos (QDs) auto-ensamblados de InAs crecidos sobre substrato de GaAs e InGaAs (substrato metamórfico). Este estudio se ha completado con experimentos de correlación de fotones emitidos por estos puntos cuánticos. En el primer análisis se realizó un estudio fundamental de las propiedades ópticas de muestras de puntos cuánticos de InAs sobre sustratos de GaAs, con el fin de comprender el comportamiento dinámico de los portadores fotogenerados dentro de un Q…
Search for the Standard Model Higgs boson in the two photon decay channel with the ATLAS detector at the LHC
2011
A search for the Standard Model Higgs boson in the two photon decay channel is reported, using 1.08 fb−11.08 fb[superscript −1] of proton–proton collision data at a centre-of-mass energy of 7 TeV recorded by the ATLAS detector. No significant excess is observed in the investigated mass range of 110–150 GeV. Upper limits on the cross-section times branching ratio of between 2.0 and 5.8 times the Standard Model prediction are derived for this mass range.
Measurement of isolated-photon pair production in pp collisions at root s=7 TeV with the ATLAS detector
2013
The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at √s = 7 TeV . The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb[superscript −1], is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (|η| 0.4, is 44.0[+3.2 over −4.2] pb. The differential cross sections as a function of the di-photon invariant mass, …
Upper limit on the cosmic-ray photon flux above 1019 eV using the surface detector of the Pierre Auger Observatory
2008
A method is developed to search for air showers initiated by photons using data recorded by the surface detector of the Auger Observatory. The approach is based on observables sensitive to the longitudinal shower development, the signal risetime and the curvature of the shower front. Applying this method to the data, upper limits on the flux of photons of 3.8 x 10-3, 2.5 x 10-3; and 2.2 x 10-3 km-2 sr-1 yr-1 above 1019 eV, 2 x 1019 eV; and 4 x 1019 eV are derived, with corresponding limits on the fraction of photons being 2.0%, 5.1%, and 31% (all limits at 95% c.l.). These photon limits disfavor certain exotic models of sources of cosmic rays. The results also show that the approach adopted…
Laboratorio Virtual de Física Cuántica
2012
El laboratorio virtual de física cuántica simula algunas de las experiencias que los estudiantes deben realizar en la asignatura Laboratorio de Física Cuántica del tercer curso del Grado en Física. Inicialmente, comenzó con la simulación del efecto fotoeléctrico y difracción de electrones. Ahora dispone de algunas simulaciones más. Este laboratorio virtual está diseñado como una herramienta para hacer más accesibles y comprensibles las experiencias del mundo cuántico y para familiarizar al estudiante con los procedimientos de medida y principios básicos de las experiencias de física cuántica. The Quantum Physics Virtual Lab simulates some of the experiences that the students must face at th…
Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
2009
From direct observations of the longitudinal development of ultra-high energy air showers performed with the Pierre Auger Observatory, upper limits of 3.8%, 2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray photons above 2, 3, 5 and 10 EeV (1 EeV equivalent to 10(18) eV), respectively. These are the first experimental limits on ultra-high energy photons at energies below 10 EeV. The results complement previous constraints on top-down models from array data and they reduce systematic uncertainties in the interpretation of shower data in terms of primary flux, nuclear composition and proton-air cross-section.