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Multiplicity dependence of K*(892)(0) and phi(1020) production in pp collisions at root s=13 TeV
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPThe striking similarities that have been observed between high-multiplicity proton-proton (pp) collisions and heavy-ion collisions can be explored through multiplicity-differential measurements of identified hadrons in pp collisions. With these measurements, it is possible to study mechanisms such as collective flow that determine the shapes of hadron transverse momentum (p(T)) spectra, to search for possible modifications of the yields of short-lived hadronic resonances due to scattering effects in an extended hadron-gas phase, and to investigate different explanations provided by phenomenological models for enhancement of strangeness production with increasing multiplicity. In this paper, these topics are addressed through measurements of the K* (892)(0) and phi(1020) mesons at midrapidity in pp collisions at root s = 13 TeV as a function of the charged-particle multiplicity. The results include the p(T) spectra, p(T)-integrated yields, mean transverse momenta, and the ratios of the yields of these resonances to those of longer-lived hadrons. Comparisons with results from other collision systems and energies, as well as predictions from phenomenological models, are also discussed.807115CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informaçãoThe ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung für Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (Finep), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Ministry of Education of China (MOEC), Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba; The Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research Natural Sciences, the Villum Fonden and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat à l'Énergie Atomique (CEA), Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS) and Région des Pays de la Loire, France; Bundesministerium für Bildung und Forschung (BMBF) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research Development and Innovation Office, Hungary; Department of Atomic Energy, Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; Indonesian Institute of Science, Indonesia; Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi and Instituto Nazionale di Fisica Nucleare (INFN), Italy; Institute for Innovative Science and Technology, Nagasaki Institute of Applied Science (IIST), Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia y Tecnología (CONACYT), through Fondo de Cooperación Internacional en Ciencia y Tecnología (FONCICYT) and Dirección General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Católica del Perú, Peru; Ministry of Science and Higher Education and National Science Centre, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics and Ministry of Research and Innovation and Institute of Atomic Physics, Romania; Joint Institute for Nuclear Research (JINR), Ministry of Education and Science of the Russian Federation, National Research Centre Kurchatov Institute, Russian Science Foundation and Russian Foundation for Basic Research, Russia; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut and Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSDTA) and Office of the Higher Education Commission under NRU project of Thailand, Thailand; Turkish Atomic Energy Agency (TAEK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America
New opportunities at the next-generation neutrino experiments I: BSM neutrino physics and dark matter
No full textSem informaçãoThe combination of the high intensity proton beam facilities and massive detectors for precision measurements of neutrino oscillation parameters including the charge-parity violating (CPV) phase will open the door to help make beyond the standard model (BSM) physics reachable even in low energy regimes in the accelerator-based experiments. Large-mass detectors with highly precise tracking and energy measurements, excellent timing resolution, and low energy thresholds will enable the searches for BSM phenomena from cosmogenic origin, as well. Therefore, it is also conceivable that BSM topics in the next-generation neutrino experiments could be the dominant physics topics in the foreseeable future, as the precision of the neutrino oscillation parameter and CPV measurements continue to improve.This paper provides a review of the current landscape of BSM theory in neutrino experiments in two selected areas of the BSM topics-dark matter and neutrino related BSM-and summarizes the current results from existing neutrino experiments to set benchmarks for both theory and experiment. This paper then provides a review of upcoming neutrino experiments throughout the next 10 to 15 year time scale and their capabilities to set the foundation for potential reach in BSM physics in the two aforementioned themes. An important outcome of this paper is to ensure theoretical and simulation tools exist to carry out studies of these new areas of physics, from the first day of the experiments, such as Deep Underground Neutrino Experiment in the U.S. and Hyper-Kamiokande Experiment in Japan.8312133Sem informaçãoSem informaçãoSem informaçãoThe authors would like to thank the University of Texas at Arlington, the Division of Particles and Fields of the American Physical Society and the U.S. Department of Energy, HEP Award No. DE-SC0019742, for providing support for the Workshop on New Opportunities at the Next Generation Neutrino Experiments held on April 12 and 13, 2019 at the University of Texas at Arlington, from which this paper originated. The authors also would like to thank the following colleagues who have endorsed this paper, although they are not authors: J Asaadi (University of Texas at Arlington), S K Agarwalla (IOPB), C Giunti (INFN Torino), S Goswami (PRL Ahmedabad), D Grant (Michigan State University), P Huber (Virginia Tech), S B Kim (Seoul National University), and S Petkov (SISSA/INFN and IPMU). The works of A C and J Y are supported by the U.S. Department of Energy, HEP Award No. DE-SC0011686. The work of B B is supported in part by the U.S. Department of Energy under Grant No. DE-SC0007914. The work of J B is supported by PITT PACC. The work of DK was supported by the Department of Energy under Grant Nos. DE-FG02-13ER41976/DE-SC0009913. P B D acknowledges the U.S. Department of Energy under Grant Contract DE-SC0012704. Y Cui is supported in part by the U.S. Department of Energy Grant DE-SC0008541. S S is supported by the National Research Foundation of Korea, NRF-2017R1D1A1B03032076. The work of J C P is supported by the National Research Foundation of Korea, NRF-2019R1C1C1005073 and NRF-2018R1A4A1025334. This manuscript is also supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
Machine learning applied to multifrequency data in astrophysics: blazar classification
No full textFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPThe study of machine learning (ML) techniques for the autonomous classification of astrophysical sources is of great interest, and we explore its applications in the context of a multifrequency data-frame. We test the use of supervised ML to classify blazars according to its synchrotron peak frequency, either lower or higher than 10(15) Hz. We select a sample with 4178 blazars labelled as 1279 high synchrotron peak (HSP: nu-peak gt; 10(15) Hz) and 2899 low synchrotron peak (LSP: nu-peak < 10(15) Hz). A set of multifrequency features were defined to represent each source that includes spectral slopes (alpha(nu 1,nu 2)) between the radio, infra-red, optical, and X-ray bands, also considering IR colours. We describe the optimization of five ML classification algorithms that classify blazars into LSP or HSP: Random forests (RFs), support vector machine (SVM), K-nearest neighbours (KNN), Gaussian Naive Bayes (GNB), and the Ludwig auto-ML framework. In our particular case, the SVM algorithm had the best performance, reaching 93 per cent of balanced accuracy. A joint-feature permutation test revealed that the spectral slopes alpha-radio-infrared (IR) and alpha-radio-optical are the most relevant for the ML modelling, followed by the IR colours. This work shows that ML algorithms can distinguish multifrequency spectral characteristics and handle the classification of blazars into LSPs and HSPs. It is a hint for the potential use of ML for the autonomous determination of broadband spectral parameters (as the synchrotron nu-peak), or even to search for new blazars in all-sky data bases.498217501764FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2017/00517-42019/08956-2BA is supported by São Paulo Research Foundation (FAPESP) with grant no. 2017/00517-4. PD is supported by São Paulo Research Foundation (FAPESP) with grant no. 2019/08956-2. We made use of archival data and bibliographic information obtained from the NASA/IPAC Extragalactic Database (NED), data and software facilities from the SSDC and Opne Universe Portals managed by the Italian Space Agency (ASI) and collaborators. We acknowledge the use of the TOPCAT and STILTS software packages (written by Mark Taylor, University of Bristol)
Unconventional enhancement of ferromagnetic interactions in Cd-doped GdFe2Zn20 single crystals studied by ESR and Fe-57 Mossbauer spectroscopies
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSingle crystals of GdFe2Zn20-xCdx (0.0 < x < 1.4) were grown and characterized through structural, magnetic, and electronic properties using x-ray diffraction, field- and temperature-dependent magnetization, specific heat, 57 Fe Mossbauer spectroscopy, and electron spin resonance (ESR). A negative chemical pressure effect is accompanied by an unexpected increase of T-C from 86 to 96 K, together with a reduction of the magnetic effective moment and saturation magnetic moment, as evidenced by all of the experimental techniques. From the microscopic point of view, probing at the 4f electron level and the Fe nucleus has allowed the extraction of important information about the configuration and the effective role of the partial Cd substitution for Zn in this ferromagnetic system. Our Fe-57 Mossbauer spectroscopy experiments show a negligible variation of the hyperfine field at the Fe site, and ESR experiments reveal an enhancement of the Korringa-type relaxation and a molecular field effect as Cd is incorporated. This complex behavior is assigned to a possible reconstruction of the Fermi surface and/or a new distribution of the d type of conduction electrons in response to the negative chemical pressure, leading to an enhancement of the ferromagnetic transition temperature in a generalized Ruderman-Kittel-Kasuya-Yosida interaction scenario.10214110CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informação2011/19924-22017/10581-1This work was supported by Brazilian agencies CNPq, CAPES, FINEP and FAPESP (Grants No. 2017/10581-1 and No. 2011/19924-2). We are thankful to the UFABC CEM for providing access to its experimental facilities
Sudden death of entanglement induced by a minimal thermal environment
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPWe study the dynamics of two interacting two-level systems (qubits) having one of them isolated and the other coupled to a single mode electromagnetic field in a thermal state. The field plays the role of a small environment, in contrast to the usual approach of modelling an environment via a thermal reservoir with many degrees of freedom. We find the analytical solution of the proposed model, which allows us to investigate the consequences of the coupling to the small environment on characteristic quantum features of the two-qubit system. We study the time evolution of quantum entanglement and coherence, verifying the dependence on the relevant coupling constants as well as the influence of the effective temperature of the environment. Interestingly, we find that both sudden death and sudden birth of entanglement may occur in such a simple system. We also discuss a different partition, in which the isolated qubit is considered to be coupled to a composite environment, constituted by the other qubit plus the field mode.47517CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP465469/2014-02008/57856-6This work was also supported by CNPq (Conselho Nacional para o Desenvolvimento Científico e Tecnológico, Brazil), through the INCT-IQ (National Institute for Science and Technology of Quantum Information), grant N 465469/2014-0, and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil) , grant N 2008/57856-6, Brazil
Structural and electronic properties of defective AlN/GaN hybrid nanostructures
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPDue to the wide range of possible applications, atomically thin two-dimensional heterostructures have attracted much attention. In this work, using first-principles calculations, we investigated the structural and electronic properties of planar AlN/GaN hybrid heterojunctions with the presence of vacancies at their interfaces. Our results reveal that a single vacancy site, produced by the removal of Aluminum or Gallium atom, yields similar electronic band structures with localized states within the bandgap. We have also observed a robust magnetic behavior. A nitrogen-vacancy, on the other hand, induces the formation of midgap states with reduced overall magnetization. We have also studied nanotubes formed by rolling up these heterojunctions. The results showed that nanotube curvature does not substantially affect the electronic and magnetic properties of their corresponding planar AlN/GaN heterojunctions. For armchair-like nanotubes, a transition from direct to indirect bandgap was observed as a consequence of changing the system geometry from 2D to a quasi-one-dimensional one.183110CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP427175/2016-0302236/2018-000193.0000248/2019-322013/08293-7The authors gratefully acknowledge the financial support from Brazilian research agencies CNPq, CAPES, and FAP-DF. L.A.R.J acknowledges the financial support from a Brazilian Research Council FAP-DF and CNPq grants 00193.0000248/2019-32 and 302236/2018-0, respectively. The authors thank CENAPAD-SP and the Laboratório de Simulação Computacional Cajuína (LSCC) at Universidade Federal do Piauí for computational support. A.L.A. acknowledges the brazilian CNPq grant (Process No. 427175/2016-0) for financial support. DSG thanks the Center for Computing in Engineering and Sciences at Unicamp for financial support through the FAPESP/CEPID Grant #2013/08293-7
Studies on the response of a water-Cherenkov detector of the Pierre Auger Observatory to atmospheric muons using an RPC hodoscope
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPExtensive air showers, originating from ultra-high energy cosmic rays, have been successfully measured through the use of arrays of water-Cherenkov detectors (WCDs). Sophisticated analyses exploitingWCD data have made it possible to demonstrate that shower simulations, based on different hadronic-interaction models, cannot reproduce the observed number of muons at the ground. The accurate knowledge of the WCD response to muons is paramount in establishing the exact level of this discrepancy. In this work, we report on a study of the response of a WCD of the PierreAuger Observatory to atmospheric muons performed with a hodoscope made of resistive plate chambers (RPCs), enabling us to select and reconstruct nearly 600 thousand single muon trajectories with zenith angles ranging from 0 degrees to 55 degrees. Comparison of distributions of key observables between the hodoscope data and the predictions of dedicated simulations allows us to demonstrate the accuracy of the latter at a level of 2%. As the WCD calibration is based on its response to atmospheric muons, the hodoscope data are also exploited to show the long-term stability of the procedure.159124CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informação1999/05404-32010/07359-62019/10151-2Departamento de Raios Cósmicos e Cronologia;Departamento de Raios Cósmicos e Cronologi
The response of boronized 34CrAlMo5-10 (EN41B) steel to nanoindentation, oxidation, and wear
No full textCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPThe present study deals with the properties of boronized and non-boronized low-alloy steel (34CrAlMo5-10). Specimens are characterised using microscopy, various spectroscopic techniques, nanoindentation, surface profilometer, and tribometer. The boronized region contains (i) (Fe, M)(2)B columns and (ii) matrix between the columns. Nanoindentation study reveals the difference in the mechanical behaviour of boride, matrix, and core regions. Strain-rate sensitivity of different regions of the specimen cross-section varies between 0.005 and 0.011. The boride phase is more sensitive to the strain-rate than matrix and core. The room-temperature oxidation resistance of the steel surface is enhanced by the presence of a higher proportion of mixed-boride and the oxide layer enriched with Cr2O3. At 550 and 850 degrees C, boronized specimens have higher oxidation resistance than the non-boronized specimens, where the layer of iron-borates protects the surface. At 200 degrees C, the boronized specimen has deprived oxidation resistance. Amongst the investigated wear-parameters, the maximum and minimum wear-resistance of the boronized surface is about 46 and 8 times the wear-resistance of the non-boronized surface, respectively. A steeper drop in the tribological advantage gained by the boronizing treatment is perceived with the increase in load, especially under higher sliding speed.142CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP465423/2014-02012/10127-52018/24461-02019/00757-02019/184602019/24095The authors would like to thank Ms. Letícia T. Bim (UCS, Brazil) and Dr. Vinod Kumar’s research-team (IITI) for the cooperation in GDOES and TGA experiments, respectively. Authors acknowledge Raman Spectrometer facility (supported by DST-FIST (grant number SR/FST/PSI-225/2016)) at Dept. of Physics, IITI. The Nanoindentor facility of IIT Bombay is also kindly acknowledged. GDOES measurements were partially supported by the Grant CNPq-INCT-INES # 465423/2014-0. XPS analysis was supported by the projects from FAPESP 2012/10127-5; 2018/24461-0; 2019/24095; 2019/18460; 2019/00757-0. CAF, FA, and VA are the CNPq fellows
Linear response theory and effective action of relativistic hydrodynamics with spin
No full textFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESWe use linear response techniques to develop the previously proposed relativistic ideal fluid limit with a non-negligible spin density. We confirm previous results [D. Montenegroet al, Phys. Rev. D 96, 056012 (2017); Phys. Rev. D 96, 079901(A) (2017); Phys. Rev. D 96, 076016 (2017); D. Montenegro and G. Torrieri, Phys. Rev. D 100, 056011 (2019)], obtain expressions for the microscopic transport coefficients using Kubo-like formulas and build up the effective field theory from the computed correlation functions. We verify that for a causal theory with spin the spin-polarization correlator's asymptotic time dependence is the same as for fluctuating hydrodynamics, and investigate backreaction corrections to hydrodynamic variables using a one-loop effective action. We also confirm that polarization makes vortices acquire an effective mass via a mechanism similar to the Anderson-Higgs mechanism in superconductors. As speculated earlier, this could stabilize the ideal hydrodynamic limit against fluctuation-driven vortices.1023115FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES2017/05685-22017/06508-7464898/2014-5301432/2017-1Sem informaçãoG. T. acknowledges support from FAPESP Grant No. 2017/06508-7, participation in FAPESP tematico 2017/05685-2 and CNPQ bolsa de produtividade 301432/2017-1. D. M. thanks CAPES for support This work is a part of the project INCT-FNA Proc. No. 464898/2014-5
Possible contamination of the Abrolhos reefs by Fundao dam tailings, Brazil – new constraints based on satellite data
No full textThe Fundão dam, located in Mariana city, Minas Gerais State, southeastern Brazil, collapsed in November 2015, causing the discharge of over 50 million m3 of iron ore tailings in the Doce river basin. The mud generated by the disaster was composed of fine particulates (silt and clay), which are more sensitive to wind dispersion. Based on laboratory analyses and hydrodynamic modeling, early research postulates the hypothesis that the mud discharged in the ocean traveled 10,000 km up north and may have reached the Abrolhos coral reefs. This research aims to investigate further this hypothesis based on broad-scale remotely sensed data. Satellite images were used to estimate the suspended particulate matter (SPM) in the coastal zone before, during, and after the dam collapse. Results indicate that higher concentrations of SPM appeared during and post-collapse and were restricted to the coastal zone and its shallower regions, including beaches. However, we demonstrate that under exceptional circumstances the wind blew to the north, carrying fine particulate material and potentially-toxic metals derived from the iron ore tailings towards the northeastern Brazilian coastline and possibly the reefs of the Abrolhos Bank733CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES309712/2017-3; 303169/2018-4Não te