Estadística en física de partícules: El seu paper en el descobriment del bosó de Higgs

L’estadística ha representat un paper d’enorme importància en el desenvolupament de la física de partícules, pionera de l’anomenada «gran ciència». La seua aplicació ha evolucionat al compàs dels progressos tecnològics, que han permès passar de registrar uns pocs centenars de «successos» a registrar-ne milers de milions. Aquest article discuteix sobre com s’ha resolt el problema de la manipulació d’aquestes quantitats massives de dades i com s’han utilitzat les principals eines estadístiques des dels anys 1990 per a cercar senyals cada vegada més petits ocults entre un soroll de fons cada vegada major. Molts experiments en la història de la física de partícules podrien il·lustrar el paper que ha exercit l’estadística, però pocs ho poden fer amb un descobriment, fruit d’un esforç tecnològic i col·lectiu colossals, de tanta repercussió científica com el del bosó de Higgs

Colloquium: Time-reversal violation with quantum-entangled B mesons

Symmetry transformations have been proven a bedrock tool for understanding the nature of particle interactions, formulating, and testing fundamental theories. Based on the up to now unbroken CPT symmetry, the violation of the CP symmetry between matter and antimatter by weak interactions, discovered in the decay of kaons in 1964 and observed more recently in 2001 in B mesons, strongly suggests that the behavior of these particles under weak interactions must also be asymmetric under time reversal T. However, until recent years there has not been a direct detection of the expected time-reversal violation in the time evolution of any system. This Colloquium examines the field of time-reversal symmetry breaking in the fundamental laws of physics. For transitions, its observation requires an asymmetry with exchange of initial and final states. A discussion is given of the conceptual basis for such an exchange with unstable particles, using the quantum properties of Einstein-Podolsky-Rosen entanglement available at B meson factories combined with the decay as a filtering measurement. The method allows a clear-cut separation of different transitions between flavor and CP eigenstates in the decay of neutral B mesons. These ideas have been implemented for the experiment by the BABAR Collaboration at SLAC's B factory. The results, presented in 2012, prove beyond any doubt the violation of time-reversal invariance in the time evolution between these two states of the neutral B meson

Laboratorio de Física Nuclear y de Partículas

Guiones de apoyo para el desarrollo de las actividades de laboratorio de la asignatura de Física Nuclear y de Partículas (1.5 créditos ECTS), cuyo material docente teórico está disponible en esta plataforma con el identificador http://roderic.uv.es/handle/10550/65281. Incluye tres bloques de experimentos: 1) Estadística de recuento y espectrometría beta con un detector Geiger-Mueller; 2) Espectroscopia gamma y vidas medias con un detector de NaI(Tl); 3) La cámara de niebla de difusión.Support scripts for the development of the laboratory activities of the subject of Nuclear and Particle Physics (1.5 ECTS credits), whose theoretical teaching material is available on this platform with identifier http://roderic.uv.es/handle/10550/65281. It includes three blocks of experiments: 1) Counting statistics and beta spectrometry with a Geiger-Mueller detector; 2) Gamma spectroscopy and half-lives with a NaI(Tl) detector; 3) The diffusion cloud chamber

Física Nuclear i de Partícules

La Física Nuclear i de Partícules és una assignatura de caràcter obligatori que s'imparteix en el primer quadrimestre de quart curs dels estudis de Grau en Física a la Universitat de València. Consta d'un total de 7.5 crèdits ECTS, dels quals 4.5 són teòrics, 1.5 teòric-pràctics (resolució de problemes), i 1.5 de laboratori. Aquesta assignatura forma part de la matèria Ampliació de Física, i permet al graduat/da adquirir coneixements bàsics sobre l'estructura de la matèria i les seues propietats. La Física Nuclear és la disciplina científica que estudia els nuclis atòmics, les seves propietats i les forces que actuen entre els seus constituents (protons i neutrons, denominats genèricament nucleons). Avui sabem que els nucleons al seu torn estan constituïts per sistemes físics àdhuc més fonamentals anomenats quarks, els quals no posseïxen estructura i són, així mateix, els constituents del que denominem partícules elementals. La Física de Partícules té per objecte l'estudi dels constituents de la matèria a la seva escala més fonamental, entendre els patrons de la “taula” de partícules elementals i quines són les propietats i lleis que regeixen les seves interaccions. Tant la Física Nuclear com la Física de Partícules tenen un caràcter de ciència fonamental, però avui dia les seves aplicacions són innombrables tant en l'àmbit científic com en l'industrial, mèdic, etc. Per tant, un plantejament modern de l'assignatura requereix una presentació tant del seu component de ciència bàsica com de ciència aplicada. Els aspectes generals en els quals radica la importància d'aquesta disciplina i que s'han considerat per a definir els continguts, orientació i plantejament de l'assignatura són els següents. En primer lloc, la comprensió de l'estructura fonamental de la matèria i de les seves interaccions ha estat i segueix sent un dels majors reptes intel·lectuals i tecnològics de l'home des de finals del segle XIX. A més, l'estudi nuclear i subnuclear de la matèria ha estat decisiu en l'evolució de la Física, basti recordar la gènesi i posterior desenvolupament de la Mecànica Quàntica, avui dia un dels fonaments bàsics de la ciència. En segon lloc, la Física Nuclear i de Partícules està relacionada amb una gran varietat d’altres àrees d’investigació de gran rellevància en l'actualitat, tals com l’Astrofísica Nuclear, les Astropartícules, Física de l'Estat Sòlid, Nanotecnologia, Computació Quàntica, etc. Y finalment, les necessitats tècniques associades al desenvolupament d'aquesta disciplina han donat lloc a un elevat nombre d'aplicacions tecnològiques que han repercutit directament en la millora de la qualitat de vida de la societat. Entre elles podríem citar els acceleradors, la medicina nuclear (tant per a diagnòstic com teràpia), fonts d'energia, aplicacions industrials de tot tipus, informàtica i telecomunicacions, protecció del medi ambient, etc.Nuclear and Particle Physics is a compulsory subject that is taught in the first quarter of the fourth year of undergraduate studies in Physics at the University of Valencia. It comprises a total of 7.5 ECTS credits, of which 4.5 are theoretical, 1.5 are theoretical-practical (problem solving), and 1.5 laboratory work. This course is part of the Expansion of Physics, and allows the graduate acquire basic knowledge about the structure of matter and its properties. Nuclear Physics is the scientific discipline that studies the atomic nuclei, their properties and the forces acting between its constituents (protons and neutrons, generically called nucleons). Today we know that nucleons are in turn composed of even more fundamental physical systems called quarks, which do not have structure and are also constituents of what we call elementary particles. Particle Physics studies the constituents of matter at its most fundamental level, understanding the patterns of elementary particles and the properties and laws governing their interactions. Both Nuclear and Particle Physics have a character of fundamental science, but today there are countless applications in several areas: scientific, industrial, medical, etc. Therefore, a modern approach to the subject requires the presentation of both basic and applied science contents. The general aspects in which lies the importance of this discipline and that have been considered to define the content and approach of the subject are the following. First, understanding the fundamental structure of matter and their interactions has been and remains today one of the greatest intellectual and technological challenges of mankind since the late nineteenth century. In addition, the study of nuclear and subnuclear matter has been instrumental in the evolution of Physics. It suffices to recall the genesis and subsequent development of Quantum Mechanics, now one of the basic foundations of science. Second, Nuclear and Particle Physics is related to a variety of research areas of great relevance today, such as Nuclear Astrophysics, Astroparticles, Solid State Physics, Nanoscience and Nanotechnology, Quantum Computation, etc…Third, technical requirements associated with the development of this discipline have led to a large number of technological applications that have direct impact on improving the life quality of society. These include accelerators, nuclear medicine (for both diagnosis and therapy), energy sources, industrial applications of all kinds, telecommunications, environmental protection, etc

Improving the performance of water distribution systems’ simulation on multicore systems

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-015-1607-5Hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDS) are used extensively, and their computational performance is key when considering optimization problems. This paper presents an approach to speedup the hydraulic solver using OpenMP with two efficient methods for WDS simulation. The paper identifies the different tasks carried out in the simulation, showing their contribution to the execution time, and selecting the target tasks for parallelization. After describing the algorithms for the selected tasks, parallel OpenMP versions are derived, with emphasis on the task of linear system update. Results are presented for four different large WDS models, showing considerable reduction in computing timeThis work has been partially supported by Ministerio de Economia y Competitividad from Spain, under the project TEC2012-38142-C04-01, and by project PROMETEO FASE II 2014/003 of Generalitat Valenciana.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2016). Improving the performance of water distribution systems’ simulation on multicore systems. Journal of Supercomputing. 1-13. https://doi.org/10.1007/s11227-015-1607-5S113Abraham E, Stoianov I (2015) Efficient preconditioned iterative methods for hydraulic simulation of large scale water distribution networks. Proc Eng 119:623–632Abraham E, Stoianov I (2015) Sparse null space algorithms for hydraulic analysis of large-scale water supply networks. J Hydraul Eng. doi: 10.1061/(ASCE)HY.1943-7900.0001089Alonso JM, Alvarruiz F, Guerrero D et al (2000) Parallel computing in water network analysis and leakage minimization. J Water Resour Plan Manag 126(4):251–260Alvarruiz F, Martínez-Alzamora F, Vidal AM (2015) Efficient simulation of water distribution systems using openmp. In: 15th International conference computational and mathematical methods in computational mathematics, science and engineering, pp 125–129Alvarruiz F, Martínez-Alzamora F, Vidal AM (2015) Improving the efficiency of the loop method for the simulation of water distribution systems. J Water Resour Plan Manag 141(10):04015019Burger G, Sitzenfrei R, Kleidorfer M, Rauch W (2015) Quest for a new solver for EPANET 2. J Water Resour Plan Manag. doi: 10.1061/(ASCE)WR.1943-5452.0000596Creaco E, Franchini M (2014) Comparison of Newton–Raphson global and loop algorithms for water distribution network resolution. J Hydraul Eng 140(3):313–321Creaco E, Franchini M (2015) The identification of loops in water distribution networks. Proc Eng 119:506–515 Computing and Control for the Water Industry (CCWI2015) Sharing the best practice in water managementCrous PA, van Zyl JE, Roodt Y (2012) The potential of graphical processing units to solve hydraulic network equations. J Hydroinf 14:603–612Elhay S, Simpson A, Deuerlein J, Alexander B, Schilders W (2014) Reformulated co-tree flows method competitive with the global gradient algorithm for solving water distribution system equations. J Water Resour Plan Manag 140(12):04014040Epp R, Fowler AG (1970) Efficient code for steady-state flows in networks. J Hydraul Div 96(1):43–56Guidolin M, Burovskiy P, Kapelan Z, Savić D (2010) Cwsnet: an object-oriented toolkit for water distribution system simulations. In: Proceedings of 12th water distribution system analysis symposium, ASCE, Reston, VAGuidolin M, Kapelan Z, Savic D (2013) Using high performance techniques to accelerate demand-driven hydraulic solvers. J Hydroinf 15(1):38–54Guidolin M, Kapelan Z, Savic D, Giustolisi O (2010) High performance hydraulic simulations with epanet on graphics processing units. In: Proceedings of 9th international conference on hydroinformaticsOstfeld A, Uber J, Salomons E et al (2008) The battle of the water sensor networks (BWSN): a design challenge for engineers and algorithms. J Water Resour Plan Manag 134(6):556–568Rossman AL (2000) Epanet 2 users manual. Water Supply and Water Resources Division, US Environment Protection AgencyTodini E, Pilati S (1988) Computer applications in water supply: vol. 1—systems analysis and simulation. In: Coulbeck B, Orr CH (eds) A gradient algorithm for the analysis of pipe networks. Research Studies Press Ltd, Letchworth, Hertfordshire, UK, pp 1–2

Improving the efficiency of the loop method for the simulation of water distribution networks

Efficiency of hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDSs) is very important, especially in the context of optimization and risk analysis problems, where the hydraulic simulation has to be repeated many times. Among the methods used for hydraulic solvers, the most prominent nowadays is the global gradient algorithm (GGA), based on a hybrid node-loop formulation. Previously, another method based just on loop flow equations was proposed, which presents the advantage that it leads to a system matrix that is in most cases much smaller than in the GGA method, but has also some disadvantages, mainly a less sparse system matrix and the fact that introducing some types of valves requires the redefinition of the set of network loops initially defined. The contribution of this paper is to present solutions for overcoming the mentioned disadvantages of the method based on loop flow equations. In particular, efficient procedures are shown for selecting the network loops so as to achieve a highly sparse matrix and methods are presented to incorporate check valves and automatic control valves while avoiding the need to redefine the loops initially selected. (C) 2015 American Society of Civil Engineers.This work has been partially supported by "Ministerio de Economia y Competitividad" from Spain, under the project TEC2012-38142-C04-01 and by PROMETEO FASE II 2014/003 project of Generalitat Valenciana.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2015). Improving the efficiency of the loop method for the simulation of water distribution networks. Journal of Water Resources Planning and Management. 141(10):1-10. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000539S1101411

Efficient Modeling of Active Control Valves in Water Distribution Systems Using the Loop Method

[EN] This paper presents a novel approach to model pressure- and flow-regulating devices in the context of the Newton-Raphson loop method for water distribution network simulation. The proposed approach uses a symmetric matrix for the underlying linear systems, which enables simpler implementation and faster solution, while producing iterations very close to the global gradient algorithm of EPANET. The structure of the matrix is kept unchanged regardless of the operational status of the valves. The paper presents results that validate its formulation, accuracy, and speed in various case studies.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2018). Efficient Modeling of Active Control Valves in Water Distribution Systems Using the Loop Method. Journal of Water Resources Planning and Management. 144(10):1-9. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000982S191441

Study of the reaction e(+)e(-) -> psi(2S)pi(+)pi(-) via initial-state radiation at BABAR

We study the process e(+)e(-) -> psi(2S)pi(+)pi(-) with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BABAR detector at center-of-mass energies at and near the (nS) (n = 2, 3, 4) resonances and correspond to an integrated luminosity of 520 fb(-1). We investigate the psi(2S)pi(+)pi(-) mass distribution from 3.95 to 5.95 GeV/c(2), and measure the center-of-mass energy dependence of the associated e(+)e(-) -> psi(2S)pi(+)pi(-) cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the psi(2S)pi(+)pi(-) mass distribution corresponding to the decay mode psi(2S) -> J/psi pi(+)pi(-) yields a mass value of 4340 +/- 16 (stat) +/- 9 (syst) MeV/c(2) and a width of 94 +/- 32 (stat) +/- 13 (syst) MeV for the first resonance, and for the second a mass value of 4669 +/- 21 (stat) +/- 3 (syst) MeV/c(2) and a width of 104 +/- 48 (stat) +/- 10 (syst) MeV. In addition, we show the pi(+)pi(-) mass distributions for these resonant regions

Simulación electromagnética FD-TD : una ayuda al diseño en compatibilidad electromagnética

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