82 research outputs found

    On the equivalence between Implicit Regularization and Constrained Differential Renormalization

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    Constrained Differential Renormalization (CDR) and the constrained version of Implicit Regularization (IR) are two regularization independent techniques that do not rely on dimensional continuation of the space-time. These two methods which have rather distinct basis have been successfully applied to several calculations which show that they can be trusted as practical, symmetry invariant frameworks (gauge and supersymmetry included) in perturbative computations even beyond one-loop order. In this paper, we show the equivalence between these two methods at one-loop order. We show that the configuration space rules of CDR can be mapped into the momentum space procedures of Implicit Regularization, the major principle behind this equivalence being the extension of the properties of regular distributions to the regularized ones.Comment: 16 page

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

    Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

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    The inclusive transverse momentum (pTp_{\rm T}) distributions of primary charged particles are measured in the pseudo-rapidity range η<0.8|\eta|<0.8 as a function of event centrality in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}}=2.76 TeV with ALICE at the LHC. The data are presented in the pTp_{\rm T} range 0.15<pT<500.15<p_{\rm T}<50 GeV/cc for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor RAAR_{\rm{AA}} using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pTp_{\rm T} particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with RAA0.13R_{\rm{AA}}\approx0.13 at pT=6p_{\rm T}=6-7 GeV/cc. Above pT=7p_{\rm T}=7 GeV/cc, there is a significant rise in the nuclear modification factor, which reaches RAA0.4R_{\rm{AA}} \approx0.4 for pT>30p_{\rm T}>30 GeV/cc. In peripheral collisions (70-80%), the suppression is weaker with RAA0.7R_{\rm{AA}} \approx 0.7 almost independently of pTp_{\rm T}. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

    Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

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    The pTp_{\rm T}-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0^0, D+^+, and D+^{*+} in the rapidity range y<0.5|y|<0.5, and for transverse momentum 1<pT<121< p_{\rm T} <12 GeV/cc, were measured in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D0^0 \rightarrow Kπ\pi, D+^+ \rightarrow Kππ\pi\pi, D+^{*+} \rightarrow D0π^0\pi, and their charge conjugates, and was performed on a Lint=1.1L_{\rm int} = 1.1 nb1^{-1} event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at s=2.76\sqrt{s} = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pTp_{\rm T}-differential production cross sections at s=2.76\sqrt{s} = 2.76 TeV and our previous measurements at s=7\sqrt{s} = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

    Database of spatial distribution of non indigenous species in Spanish marine waters

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    Research in marine Spanish waters are focused on several actions to achieve an effectively management on protected areas, with the active participation of the stakeholders and research as basic tools for decision-making. Among these actions, there is one about the knowledge and control on NIS. One of its objectives is the creation of NIS factsheets, which are going to be added to the National Marine Biodiversity Geographical System (GIS) providing complementary information about taxonomic classification, common names, taxonomic synonyms, species illustrations, identification morphological characters, habitat in the native and introduced regions, biological and ecological traits, GenBank DNA sequences, world distribution, first record and evolution in the introduced areas, likely pathways of introduction, effects in the habitats and interaction with native species, and potential management measures to apply. The database will also provide data for (1) the European online platforms, (2) the environmental assessment for the Descriptor 2 (D2-NIS) of the EU Marine Strategy Framework Directive (MSFD), as well as (3) supporting decisions made by stakeholders. It is the result of extensive collaboration among scientist, manager’s and citizen science in the Spanish North-Atlantic, South-Atlantic, Gibraltar Strait-Alboran, Levantine-Balearic and Canary Islands marine divisions, providing an updated overview of the spatial distribution of relevant extended and invasive NIS of recent and established NIS introduced by maritime transport and aquaculture pathways, as well as on cryptogenic or native species in expansion due to the climatic water warming trend

    Consenso Mexicano para el Tratamiento de la Hepatitis C

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    El objetivo del Consenso Mexicano para el Tratamiento de la Hepatitis C fue el de desarrollar un documento como guía en la práctica clínica con aplicabilidad en México. Se tomó en cuenta la opinión de expertos en el tema con especialidad en: gastroenterología, infectología y hepatología. Se realizó una revisión de la bibliografía en MEDLINE, EMBASE y CENTRAL mediante palabras claves referentes al tratamiento de la hepatitis C. Posteriormente se evaluó la calidad de la evidencia mediante el sistema GRADE y se redactaron enunciados, los cuales fueron sometidos a voto mediante un sistema modificado Delphi, y posteriormente se realizó revisión y corrección de los enunciados por un panel de 34 votantes. Finalmente se clasificó el nivel de acuerdo para cada oración. Esta guía busca dar recomendaciones con énfasis en los nuevos antivirales de acción directa y de esta manera facilitar su uso en la práctica clínica. Cada caso debe ser individualizado según sus comorbilidades y el manejo de estos pacientes siempre debe ser multidisciplinario. Abstract The aim of the Mexican Consensus on the Treatment of Hepatitis C was to develop clinical practice guidelines applicable to Mexico. The expert opinion of specialists in the following areas was taken into account: gastroenterology, infectious diseases, and hepatology. A search of the medical literature was carried out on the MEDLINE, EMBASE, and CENTRAL databases through keywords related to hepatitis C treatment. The quality of evidence was subsequently evaluated using the GRADE system and the consensus statements were formulated. The statements were then voted upon, using the modified Delphi system, and reviewed and corrected by a panel of 34 voting participants. Finally, the level of agreement was classified for each statement. The present guidelines provide recommendations with an emphasis on the new direct-acting antivirals, to facilitate their use in clinical practice. Each case must be individualized according to the comorbidities involved and patient management must always be multidisciplinary

    Transverse momentum spectra of charged particles in proton-proton collisions at s=900\sqrt{s} = 900 GeV with ALICE at the LHC

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    The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at s=900\sqrt{s} = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (η<0.8)(|\eta|<0.8) over the transverse momentum range 0.15<pT<100.15<p_{\rm T}<10 GeV/cc. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for η<0.8|\eta|<0.8 is <pT>INEL=0.483±0.001\left<p_{\rm T}\right>_{\rm INEL}=0.483\pm0.001 (stat.) ±0.007\pm0.007 (syst.) GeV/cc and \left_{\rm NSD}=0.489\pm0.001 (stat.) ±0.007\pm0.007 (syst.) GeV/cc, respectively. The data exhibit a slightly larger <pT>\left<p_{\rm T}\right> than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET.Comment: 20 pages, 8 figures, 2 tables, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/390

    Inclusive J/psi production in pp collisions at sqrt(s) = 2.76 TeV

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    The ALICE Collaboration has measured inclusive J/psi production in pp collisions at a center of mass energy sqrt(s)=2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y|<0.9 and 2.5<y<4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are L^e_int=1.1 nb^-1 and L^mu_int=19.9 nb^-1, and the corresponding signal statistics are N_J/psi^e+e-=59 +/- 14 and N_J/psi^mu+mu-=1364 +/- 53. We present dsigma_J/psi/dy for the two rapidity regions under study and, for the forward-y range, d^2sigma_J/psi/dydp_t in the transverse momentum domain 0<p_t<8 GeV/c. The results are compared with previously published results at sqrt(s)=7 TeV and with theoretical calculations.Comment: 7 figures, 3 tables, accepted for publication in Phys. Lett.

    Measurement of jet suppression in central Pb-Pb collisions at root s(NN)=2.76 TeV

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    The transverse momentum(p(T)) spectrum and nuclear modification factor (R-AA) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at root s(NN) = 2.76 TeV were measured. Jets were reconstructed using the anti-k(T) jet algorithm with a resolution parameter of R = 0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet p(T) spectra are reported in the pseudorapidity interval of \eta(jet)\ 5 GeV/c to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb-Pb collisions had a negligible effect on the R-AA. The nuclear modification factor R-AA was found to be 0.28 +/- 0.04 in 0-10% and 0.35 +/- 0.04 in 10-30% collisions, independent of p(T), jet within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe

    Neutral pion and η\eta meson production in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV and s=7\sqrt{s}=7 TeV

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    The first measurements of the invariant differential cross sections of inclusive π0\pi^0 and η\eta meson production at mid-rapidity in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV and s=7\sqrt{s}=7 TeV are reported. The π0\pi^0 measurement covers the ranges 0.4<pT<70.4<p_T<7 GeV/cc and 0.3<pT<250.3<p_T<25 GeV/cc for these two energies, respectively. The production of η\eta mesons was measured at s=7\sqrt{s}=7 TeV in the range 0.4<pT<150.4<p_T<15 GeV/cc. Next-to-Leading Order perturbative QCD calculations, which are consistent with the π0\pi^0 spectrum at s=0.9\sqrt{s}=0.9 TeV, overestimate those of π0\pi^0 and η\eta mesons at s=7\sqrt{s}=7 TeV, but agree with the measured η/π0\eta/\pi^0 ratio at s=7\sqrt{s}=7 TeV.Comment: 17 pages, 5 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/310
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