Search results for "Ford"
showing 10 items of 785 documents
Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
2012
We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal (process independent). We show that this strict (process-independent) factorization is not valid at one-loop and higher-loop orders in the case of the collinear limit in space-like regions (e.g., collinear radiation from initial-state partons). We introduce a generalized version of all-order collinear factorization, in which the space-like singular factors retain some dependence on the momentum a…
Double collinear splitting amplitudes at next-to-leading order
2013
We compute the next-to-leading order (NLO) QCD corrections to the $1 \to 2$ splitting amplitudes in different dimensional regularization (DREG) schemes. Besides recovering previously known results, we explore new DREG schemes and analyze their consistency by comparing the divergent structure with the expected behavior predicted by Catani's formula. Through the introduction of scalar-gluons, we show the relation among splittings matrices computed using different schemes. Also, we extended this analysis to cover the double collinear limit of scattering amplitudes in the context of QCD+QED.
Triple collinear splitting functions at NLO for scattering processes with photons
2014
We present splitting functions in the triple collinear limit at next-to-leading order. The computation was performed in the context of massless QCD+QED, considering only processes which include at least one photon. Through the comparison of the IR divergent structure of splitting amplitudes with the expected known behavior, we were able to check our results. Besides that we implemented some consistency checks based on symmetry arguments and cross-checked the results among them. Studying photon-started processes, we obtained very compact results.
What is a singular black hole beyond general relativity?
2017
Exploring the characterization of singular black hole spacetimes, we study the relation between energy density, curvature invariants, and geodesic completeness using a quadratic $f(R)$ gravity theory coupled to an anisotropic fluid. Working in a metric-affine approach, our models and solutions represent minimal extensions of General Relativity (GR) in the sense that they rapidly recover the usual Reissner-Nordstr\"{o}m solution from near the inner horizon outwards. The anisotropic fluid helps modify only the innermost geometry. Depending on the values and signs of two parameters on the gravitational and matter sectors, a breakdown of the correlations between the finiteness/divergence of the…
Measurement of CP asymmetry in D 0 → K - K + and D 0 → π - πdecays
2014
Time-integrated $CP$ asymmetries in $D^0$ decays to the final states $K^- K^+$ and $\pi^- \pi^+$ are measured using proton-proton collisions corresponding to $3\mathrm{\,fb}^{-1}$ of integrated luminosity collected at centre-of-mass energies of $7\mathrm{\,Te\kern -0.1em V}$ and $8\mathrm{\,Te\kern -0.1em V}$. The $D^0$ mesons are produced in semileptonic $b$-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in $CP$ asymmetries between the two final states is measured to be \begin{align} \Delta A_{CP} = A_{CP}(K^-K^+)-A_{CP}(\pi^-\pi^+) = (+0.14 \pm 0.16\mathrm{\,(stat)} \pm 0.08\mathrm{\,(syst)})\% \ . \nonu…
Initial results on energy resolution of the NEXT-White detector
2018
One of the major goals of the NEXT-White (NEW) detector is to demonstrate the energy resolution that an electroluminescent high pressure xenon TPC can achieve for high energy tracks. For this purpose, energy calibrations with 137Cs and 232Th sources have been carried out as a part of the long run taken with the detector during most of 2017. This paper describes the initial results obtained with those calibrations, showing excellent linearity and an energy resolution that extrapolates to approximately 1% FWHM at Q$_{\beta\beta}$.
Las batallas de Atapuerca y la (re)escritura novelesca de la historia
2020
La batalla de Atapuerca (1054) constituye un hito en la historia del reino de Navarra. Desde su primera versión historiográfica conservada en la Historia silense (c. 1118-1126), el relato de la batalla de Atapuerca sufrió modificaciones, amplificaciones y refundiciones en su extensa dispersión en el tiempo y el espacio. En este trabajo se lleva a cabo, en un primer momento, una comparación entre distintas versiones latinas (fundamentalmente la Silense, el Chronicon mundi y De rebus Hispaniae) y castellanas de este episodio para luego dar lugar al análisis de una versión tardía del enfrentamiento incluida en el manuscrito 431 de la Biblioteca Nacional de España, códice que dataría de la segu…
Ancient human genomes suggest three ancestral populations for present-day Europeans
2014
We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes1,2,3,4 with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians3, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these popula…
LA QUESTIONE ABITATIVA TRA SOSTENIBILITÀ SOCIALE E DINAMICHE IMMOBILIARI
2017
Questo studio si propone di delineare una metodologia di valutazione dell’housing affordability alla scala territoriale, intesa come accessibilità finanziaria all’abitazione, in modo da ottenere un sistema di informazioni da impiegare a supporto del processo decisionale pubblico sulle politiche abitative. L’obiettivo, in particolare, è quello di individuare la domanda locale e i bisogni sociali corrispondenti alla distribuzione territoriale dei gap reddituali che impediscono l’accesso all’abitazione, in modo da intervenire con tutti gli strumenti che consentono di raggiungere una maggiore equità sociale. La metodologia procede attraverso lo studio della distribuzione territoriale della ricc…
Notes on privacy from the jurisprudence of the Inter-American Court of Human Rights
2013
En el presente artículo los profesores Zelada y Bertoni realizan un minucioso e interesante estudio del artículo 11 de la Convención Americana sobre Derechos Humanos a través de la jurisprudencia de la Corte Interamericana de Derechos Humanos. In this paper, professors Zelada and Bertoni perform a thorough and interesting study of Paper 11 of the American Convention on Human Rights analyzing the jurisprudence of the Inter-American Court of Human Rights.