2,276 research outputs found

    Overview of Spanish Tracking R&D for FLC

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    An overview of the present and foreseen R&D activities of the Spanish network for future accelerators aiming to participate in the design and construction of the forward tracker and vertex detectors of the Future Linear Colliders, is shown.Comment: 7 pages, 8 Figures, LCWS10 Conference Proceeding

    Spectral energy distribution of hyperluminous infrared galaxies

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    Aims. The relationship between star formation and super-massive black hole growth is central to our understanding of galaxy formation and evolution. Hyperluminous infrared galaxies (HLIRG) are unique laboratories to investigate the connection between starburst (SB) and active galactic nuclei (AGN), because they exhibit extreme star-formation rates, and most of them show evidence of harbouring powerful AGN. Methods. Our previous X-ray study of a sample of HLIRG shows that the X-ray emission of most of these sources is dominated by AGN activity. To improve our estimate of the relative contribution of the AGN and SB emission to its total bolometric output, we have built multi-wavelength (from radio to X-rays) spectral energy distributions (SED) for these HLIRG and fitted standard empirical AGN and SB templates to these SED. Results. In broad terms, most sources are well fitted with this method, and we found AGN and SB contributions similar to those obtained by previous studies of HLIRG. We have classified the HLIRG SED into two groups, class A and class B. Class A HLIRG show a flat SED from the optical to the infrared energy range. Three out of seven class A sources can be modelled with a pure luminosity-dependent quasar template, while the rest of them require a type 1 AGN template and a SB template. The SB component is dominant in three out of four class A objects. Class B HLIRG show SED with a prominent and broad IR bump. These sources cannot easily be modelled with a combination of pure AGN and pure SB, they require templates of composite objects, suggesting that >‚ąľ50% of their emission comes from stellar formation processes. Conclusions. We propose that our sample is actually composed of three different populations: very luminous quasars (class A objects with negligible SB contribution), young galaxies going through their maximal star-formation period (class A objects with significant SB emission) and the high luminosity tail of the ultraluminous infrared galaxies population distribution (class B sources).We are grateful to the referee M. Rowan-Robinson for the constructive comments and suggestions that improved this paper. A.R. acknowledges support from a Universidad de Cantabria fellowship and from ASI grant n. ASI I/088/06/0. Financial support for A.R. and F.J.C. was provided by the Spanish Ministry of Education and Science, under projects ESP2003-00812 and ESP2006-13608-C02-01. FP acknowledges financial support under the project ASI INAF I/08/07/0. G.M. thanks the Ministerio de Ciencia e Innovaci√≥n and CSIC for support through a Ram√≥n y Cajal contract. This research made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This paper is based also on data from the VOSED tool at LAEFF. The 2.5 m Isaac Newton Telescope and its service programme are operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrof√≠sica de Canarias

    Divulgação em física de partículas: masterclasses internacionais concurso CERN-Beamline e o grupo internacional de divulgação em física de partículas

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    La red internacional de cient√≠ficos y comunicadores IPPOG ("International Particle Physics Outreach Group") tiene como objetivo divulgar y educar en f√≠sica de part√≠culas. La estructura elemental de la materia y la din√°mica que rige su comportamiento las muestra al gran p√ļblico mediante diversas actividades que tratan de fortalecer la curiosidad por la cultura cient√≠fica. En este art√≠culo, que fu√© presentado en la Bienal de la Real Sociedad de F√≠sica celebrada en Gij√≥n, en 2015, se muestra resumidamente una de sus actividades de mayor √©xito, las Clases Magistrales Internacionales ("International Masterclasses") en F√≠sica de Part√≠culas. Adem√°s se presenta una actividad desarrollada por el CERN para mantener el inter√©s de estudiantes de ense√Īanza secundaria por la f√≠sica que se desarrolla en las grandes instalaciones cient√≠ficas, el concurso "CERN Beamline". Los miembros del IPPOG act√ļan en el mismo como colaboradores expertos.A rede internacional de cientistas e comunicadores IPPOG ("International Particle Physics Outreach Group") tem como objectivo a divulga√ß√£o e educa√ß√£o em f√≠sica de part√≠culas. A estrutura elementar da mat√©ria e a din√Ęmica que rege o seu comportamento s√£o mostradas ao p√ļblico em geral atrav√©s de v√°rias actividades que visam refor√ßar a curiosidade pela cultura cient√≠fica. Este artigo, que foi apresentado na Bienal da Royal Physical Society realizada em Gij√≥n em 2015, resume uma das suas actividades de maior sucesso, as Masterclasses Internacionais de F√≠sica de Part√≠culas. Al√©m disso, √© apresentada uma actividade desenvolvida pelo CERN para manter o interesse dos estudantes do ensino secund√°rio na f√≠sica que tem lugar em grandes instala√ß√Ķes cient√≠ficas, o concurso "CERN Beamline". Os membros do IPPOG actuam como colaboradores peritos neste concurso

    Modified spinning black holes

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    In the context of f(R) modified gravity theories we determine that the black holes existence is determined by the sign of a parameter dependent of the mass, the charge, the spin and the scalar curvature. We obtain the different astrophysical objects derived from the presence of different horizons. Thermodynamics for this kind of black holes is studied for negative values of the curvature, revealing that we can distinguish between two kind of BH: fast and slow

    Estudio y c√°lculo para la selecci√≥n de una torre de enfriamiento en la Compa√Ī√≠a Colombiana de Clinker S.A. (COLCLINKER) /

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    El objetivo de este estudio es darle soluci√≥n a los problemas de sedimentaci√≥n, obstrucci√≥n y corrosi√≥n en la tuber√≠a de recirculaci√≥n de agua enfriante, y recalentamiento de equipos que necesitan refrigeraci√≥n por agua en la planta. Mediante la implementaci√≥n de una Torre de Enfriamiento se realiza un estudio del calor generado por dichos equipos los cuales presentan a su vez condiciones de trabajo como: Temperatura de entrada y de salida, di√°metro de tuber√≠a, caudal y presi√≥n de trabajo. Con estos datos y teniendo en cuenta la temperatura del aire bulbo h√ļmedo y bulbo seco, temperatura m√≠nima de entrada y con el caudal total necesario para todos los equipos se procede a seleccionar la Torre de Enfriamiento. Para evitar la formaci√≥n de incrustaciones fouling y dep√≥sitos en general se dise√Īa un plan de ataque qu√≠mico para el agua de enfriamiento. Para un buen control se describe la dosificaci√≥n y periodicidad de cada uno de los productos qu√≠micos utilizados para este fin. Para un monitoreo continuo se recomiendan equipos especiales que facilitaran los datos que se requieran en cualquier momento. Para evitar que se produzcan paradas inesperadas de los equipos por fallas mec√°nicas de la Torre de Enfriamiento se dise√Īo un plan de mantenimiento a sus ventiladores, motores, bombas, estructura, caja reductora, tanque y red de tuber√≠a. En cuanto a la ubicaci√≥n se tuvieron en cuenta los estudios de suelo, radiaci√≥n solar, carga de contacto direcci√≥n y velocidad del viento. Se dise√Ī√≥ la red de tuber√≠a, la cual de acuerdo con las caracter√≠sticas y condiciones de la distribuci√≥n de los equipos, se defini√≥ como un sistema de recirculaci√≥n abierto con colector de retorno inverso con tramos de verticales de retorno libre.Incluye bibliograf√≠

    Measurement of the WW and WZ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set

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    et al.We present a measurement of the total WW and WZ production cross sections in pp¬Į collision at ‚ąös=1.96 TeV, in a final state consistent with leptonic W boson decay and jets originating from heavy-flavor quarks from either a W or a Z boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb-1. An analysis of the dijet mass spectrum provides 3.7ŌÉ evidence of the summed production processes of either WW or WZ bosons with a measured total cross section of ŌÉWW+WZ=13.7¬Ī3.9 pb. Independent measurements of the WW and WZ production cross sections are allowed by the different heavy-flavor decay patterns of the W and Z bosons and by the analysis of secondary-decay vertices reconstructed within heavy-flavor jets. The productions of WW and of WZ dibosons are independently seen with significances of 2.9ŌÉ and 2.1ŌÉ, respectively, with total cross sections of ŌÉWW=9.4¬Ī4.2 pb and ŌÉWZ=3.7-2.2+2.5 pb. The measurements are consistent with standard-model predictions.This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A. P. Sloan Foundation; the Bundesministerium f√ľr Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovaci√≥n, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; the Academy of Finland; and the Australian Research Council (ARC).Peer Reviewe

    High-precision measurement of the W boson mass with the CDF II detector

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    The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera‚Äďelectron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain MW=80,433.5¬Ī6.4stat¬Ī6.9syst=80,433.5¬Ī9.4 MeV/c2 , the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega‚Äďelectron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.Funding:This work wassupported by the US Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology ofJapan; the Natural Sciences and Engineering Research Councilof Canada; the National Science Council of the Republic of China; theSwiss National Science Foundation; the Alfred P. Sloan Foundation;the Bundesministerium f√ľr Bildung und Forschung, Germany; the National Research Foundation of Korea; the Science and TechnologyFacilities Council and the Royal Society, UK; the Russian Foundationfor Basic Research; the Ministerio de Ciencia e Innovaci√≥n, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency;the Academy of Finland; and the Australian Research Council (ARC)

    First measurement of the forward-backward asymmetry in bottom-quark pair production at high mass

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    Under the terms of the Creative Commons Attribution license.-- et al.We measure the particle-level forward-backward production asymmetry in bb¬Į pairs with masses (mbb¬Į) larger than 150 GeV/c2, using events with hadronic jets and employing jet charge to distinguish b from b¬Į. The measurement uses 9.5 fb-1 of pp¬Į collisions at a center-of-mass energy of 1.96 TeV recorded by the CDF II detector. The asymmetry as a function of mbb¬Į is consistent with zero, as well as with the predictions of the standard model. The measurement disfavors a simple model including an axigluon with a mass of 200 GeV/c2, whereas a model containing a heavier 345 GeV/c2 axigluon is not excluded.This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A. P. Sloan Foundation; the Bundesministerium f√ľr Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, United Kingdom; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovaci√≥n, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; the Academy of Finland; the Australian Research Council; and the EU community Marie Curie Fellowship Contract No. 302103.Peer Reviewe

    Measurement of the cross section for direct-photon production in association with a heavy quark in ppŐĄ collisions at ‚ąös=1.96 TeV

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    We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of ‚ąös=1.96 TeV proton-antiproton collisions corresponding to 9.1 fb -1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yő≥|20 GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions. ¬© 2013 American Physical Society.This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A. P. Sloan Foundation; the Bundesministerium f√ľr Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovaci√≥n, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; the Academy of Finland; the Australian Research Council (ARC); and the EU community Marie Curie Fellowship Contract No. 302103.Peer Reviewe
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