Search results for "partícules"
showing 10 items of 522 documents
Estudi de la immunogenicitat de Norovirus humans i de la seua interacció amb receptors cel·lulars
2014
Noroviruses (NoVs) are the main cause of sporadic cases and outbreaks of acute gastroenteritis (Tam et al., 2012; Gastanaduy et al., 2013) and are globally associated with a large burden of disease (Patel et al., 2008). NoVs are a highly diverse group of viruses, although over the past two decades most reported NoV outbreaks and epidemics have been caused by NoV GII.4 genotype. Phylogenetic analyses of the GII.4 strains circulating in the last 20 years have shown that this genotype can be divided into distinct variants, which peak and wane over time in a similar pattern to that described for influenza viruses (Buesa et al., 2008; Siebenga et al., 2009; Koelle et al., 2006). In recent years …
Search for weakly decaying b -flavored pentaquarks
2018
Investigations of the existence of pentaquark states containing a single $b$ (anti)quark decaying weakly into four specific final states J/$\psi K^+\pi^- p$, J/$\psi K^- \pi^- p$, J/$\psi K^- \pi^+ p$, and $J/\psi \phi (1020) p$ are reported. The data sample corresponds to an integrated luminosity of 3.0/fb in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed and upper limits are set on the product of the production cross section times branching fraction with respect to that of the $\Lambda_b$.
Estadística en física de partícules: El seu paper en el descobriment del bosó de Higgs
2014
L’estadistica ha representat un paper d’enorme importancia en el desenvolupament de la fisica de particules, pionera de l’anomenada «gran ciencia». La seua aplicacio ha evolucionat al compas dels progressos tecnologics, que han permes 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 manipulacio d’aquestes quantitats massives de dades i com s’han utilitzat les principals eines estadistiques des dels anys 1990 per a cercar senyals cada vegada mes petits ocults entre un soroll de fons cada vegada major. Molts experiments en la historia de la fisica de particules podrien il·lustrar el paper q…
Searches for lepton number violating $K^+$ decays
2019
The NA62 experiment at CERN reports a search for the lepton number violating decays K+ -> pi(-)e(+)e(+) and K+ -> pi(-)mu(+)mu(+) using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2 x 10(-10) and 4.2 x 10(-11) are obtained, respectively, at 90% confidence level. These upper limits improve on previously reported measurements by factors of 3 and 2, respectively.
Observation of the rare B(s)(0) + decay from the combined analysis of CMS and LHCb data.
2015
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported licence.-- et al.
Measurement of the top quark pair production cross-section with ATLAS in the single lepton channel
2012
A measurement of the production cross-section for top quark pairs (t[bar over t]) in pp collisions at √s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in the single lepton topology by requiring an electron or muon, large missing transverse momentum and at least three jets. With a data sample of 35 pb[superscript −1], two different multivariate methods, one of which uses b-quark jet identification while the other does not, use kinematic variables to obtain cross-section measurements of σ[subscript t bar over t] = 187 ± 11 (stat.) [+18 over −17] (syst.) ± 6 (lumi.) pb and σ[subscript t bar over t] = 173 ± 17 (stat.) [+18 ove…
Jet mass and substructure of inclusive jets in $ \sqrt {s} = 7\;{\text{TeV}} $ pp collisions with the ATLAS experiment
2012
Recent studies have highlighted the potential of jet substructure techniques to identify the hadronic decays of boosted heavy particles. These studies all rely upon the assumption that the internal substructure of jets generated by QCD radiation is well understood. In this article, this assumption is tested on an inclusive sample of jets recorded with the ATLAS detector in 2010, which corresponds to 35 pb-1 of pp collisions delivered by the LHC at √s = 7TeV. In a subsample of events with single pp collisions, measurements corrected for detector efficiency and resolution are presented with full systematic uncertainties. Jet invariant mass, kt splitting scales and N-subjettiness variables are…
Aproximació a la partícula "idò", valors i melodies
2010
L’article vol ser una primera aproximació als usos actuals de la partícula catalana idò. Àmpliament utilitzada en la parla col·loquial i espontània de les Illes Balears, la partícula parteix d’usos comuns amb el seu originari doncs (fr. donc, it. dunque), però ha anat prenent altres valors, tot i mantenir una notable simetria. Al costat de valors consecutius i de marcador discursiu pot funcionar com a element interrogatiu i interjecció. Com sovint s’esdevé amb certes partícules, idò pren valors lligats a l’entonació, que permetrà destriar retolacions i significats.
Les partícules modals alemanyes i els seus equivalents en català des d'una perspectiva contrastiva
2001
In this paper we present a first approach to the German modal particles and their equivalents in Catalan. The German modal particles are a word group described in the German linguistics with functional criteria which does not exist in any romance language: this is also the case with Catalan. The meaning of modal particles belongs to the pragmatic level and is related to the speaker’s attitudes, but modal particles show some other discursive properties as well. Firstly, German modal particles as a linguistic phenomenon will be described. Secondly, some of their equivalents in Catalan will be established by means of comparing original literary texts in German and their translation into Catala…
Development of the quality test protocol for the DEPFET pixel detectors and top-quark mass measurement at high energy e+e- colliders
2017
El Modelo Estándar (SM) es el marco teórico más preciso jamas construido, el cual incluye todas las partículas descubiertas y las interacciones entre ellas. Es el resultado de más de 100 años de investigación en física de partículas, empezando por las observaciones de J.J. Thompson de los así llamados “corpusculos”, usando un pequeño tubo de rayos catódicos; hasta el reciente descubrimiento del bosón de Higgs, que ha necesitado de la colaboración de miles de científicos de todo el mundo, así como la mayor y más sofisticada máquina jámas construida por el ser humano (el LHC). La necesidad de entender los fenómenos de la naturaleza es imparable, así como la creación de nu…