76 research outputs found

    Afirmação da identidade étnico-racial em crianças quilombolas e não quilombolas

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    AFFIRMATION OF ETHNIC-RACIAL IDENTITY IN QUILOMBOLA AND NON-QUILOMBOLA CHILDREN AFIRMACIÓN DE IDENTIDAD ÉTNICO-RACIAL EN NIÑOS QUILOMBOLAS Y NO QUILOMBOLAS ResumoAnalisa-se em dois estudos a identidade étnico-racial de crianças brancas, negras quilombolas e não quilombolas. No estudo 1, participaram 179 crianças negras e brancas, 54% de sexo feminino, 31% com idades entre seis e sete anos e o restante com idades entre oito e dez anos. Os resultados indicaram que as crianças brancas apresentam uma maior identificação com a cor da sua pele que as negras e que as negras não quilombolas são as que menos se auto identificam como negras. O segundo estudo, realizado oito meses depois, adotou um delineamento quase-experimental para testar o efeito de um conto de fadas na afirmação da identidade étnica das crianças negras. Participaram 29 crianças cujas identidades haviam sido analisadas no primeiro estudo, 16 de sexo feminino, sendo 12 delas com idades entre seis e sete anos. As crianças ouviam um conto de fadas cujos protagonistas eram todos negros e, em seguida, participavam da mesma entrevista do Estudo 1. Os resultados indicaram que a afirmação identitária se tornou mais forte, o reconhecimento de pertencimento étnico cresceu de 50% para mais de 70% e o sentimento de gostar de pertencer ao grupo aumentou também de forma significativa. No geral, os resultados obtidos apontam a importância integrada de Políticas Públicas de valorização identitária e ações voltadas para a representação simbólica dos grupos nos espaços de poder sobre a identidade étnica das crianças.Palavras-chave: Afirmação da identidade, Identidade negra, Infância, Quilombola. AbstractIn two studies, the ethnic-racial identity of white, black quilombola and non-quilombola children is analyzed. In study 1, 179 black and white children participated, 54% female, 31% aged between six and seven years and the remainder aged between eight and ten years. The results indicated that white children have a greater identification with the color of their skin than black women and that non-quilombola black women are the ones that least identify themselves as black. The second study, carried out eight months later, adopted a quasi-experimental design to test the effect of a fairy tale on the affirmation of the ethnic identity of black children. Twenty-nine children participated, whose identities had been analyzed in the first study, 16 female, 12 of them aged between six and seven years. The children listened to a fairy tale whose protagonists were all black and then participated in the same interview as in Study 1. The results indicated that the identity statement became stronger, the recognition of ethnic belonging grew from 50% to over 70 % and the feeling of enjoying belonging to the group also increased significantly. In general, the results obtained point to the integrated importance of Public Policies for the valorization of identity and actions aimed at the symbolic representation of groups in spaces of power over the children's ethnic identity.Keywords: Affirmation of identity, Black identity, Childhood, Quilombola ResumenEn dos estudios, se analiza la identidad étnico-racial de los niños blancos, negros quilombolas y no quilombolas. En el estudio 1, participaron 179 niños blancos y negros, 54% mujeres, 31% de edades comprendidas entre seis y siete años y el resto entre ocho y diez años. Los resultados indicaron que los niños blancos tienen una mayor identificación con el color de su piel que las mujeres negras y que las mujeres negras no quilombolas son las que menos se identifican como negras. El segundo estudio, llevado a cabo ocho meses después, adoptó un diseño cuasiexperimental para evaluar el efecto de un cuento de hadas en la afirmación de la identidad étnica de los niños negros. Participaron veintinueve niños, cuyas identidades habían sido analizadas en el primer estudio, 16 mujeres, 12 de ellas de entre seis y siete años. Los niños escucharon un cuento de hadas cuyos protagonistas eran todos negros y luego participaron en la misma entrevista que en el Estudio 1. Los resultados indicaron que la declaración de identidad se hizo más fuerte, el reconocimiento de pertenencia étnica creció del 50% a más de 70 % y la sensación de disfrutar pertenecer al grupo también aumentó significativamente. En general, los resultados obtenidos apuntan a la importancia integrada de las Políticas Públicas para la valorización de la identidad y las acciones dirigidas a la representación simbólica de los grupos en espacios de poder sobre la identidad étnica de los niños.Palabras llave: afirmación de identidade, Identidad negra, Infancia, Quilombol

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurement of the correlation between the polar angles of leptons from top quark decays in the helicity basis at √s = 7 TeV using the ATLAS detector

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    A measurement of the correlations between the polar angles of leptons from the decay of pair-produced t and t̄ quarks in the helicity basis is reported, using proton-proton collision data collected by the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 4.6  fb−¹ at a center-of-mass energy of √s = 7  TeV collected during 2011. Candidate events are selected in the dilepton topology with large missing transverse momentum and at least two jets. The angles θ1 and θ2 between the charged leptons and the direction of motion of the parent quarks in the tt̄ rest frame are sensitive to the spin information, and the distribution of cosθ1 ⋅ cosθ2 is sensitive to the spin correlation between the t and t̄ quarks. The distribution is unfolded to parton level and compared to the next-to-leading order prediction. A good agreement is observed

    Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at √s = 8 TeV with the ATLAS detector

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    Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at √s=8  TeV corresponding to an integrated luminosity of 20.3  fb−1 collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios

    Measurement of the CP-violating phase ϕs and the Bs0 meson decay width difference with Bs0 → J/ψϕ decays in ATLAS

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    A measurement of the Bs0 decay parameters in the Bs0 → J/ψϕ channel using an integrated luminosity of 14.3 fb−1 collected by the ATLAS detector from 8 TeV pp collisions at the LHC is presented. The measured parameters include the CP -violating phase ϕs, the decay width Γs and the width difference between the mass eigenstates ΔΓs. The values measured for the physical parameters are statistically combined with those from 4.9 fb−1 of 7 TeV data, leading to the following: ϕ s =−0.090±0.078(stat.)±0.041(syst.)rad ΔΓ s =0.085±0.011(stat.)±0.007(syst.)ps −1 Γ s =0.675±0.003(stat.)±0.003(syst.)ps −1 In the analysis the parameter ΔΓs is constrained to be positive. Results for ϕs and ΔΓs are also presented as 68% and 95% likelihood contours in the ϕs-ΔΓs plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Measurement of the differential cross-section of highly boosted top quarks as a function of their transverse momentum in s =8 TeV proton-proton collisions using the ATLAS detector

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    The differential cross-section for pair production of top quarks with high transverse momentum is measured in 20.3  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The measurement is performed for tt¯ events in the lepton+jets channel. The cross-section is reported as a function of the hadronically decaying top quark transverse momentum for values above 300 GeV. The hadronically decaying top quark is reconstructed as an anti-kt jet with radius parameter R=1.0 and identified with jet substructure techniques. The observed yield is corrected for detector effects to obtain a cross-section at particle level in a fiducial region close to the event selection. A parton-level cross-section extrapolated to the full phase space is also reported for top quarks with transverse momentum above 300 GeV. The predictions of a majority of next-to-leading-order and leading-order matrix-element Monte Carlo generators are found to agree with the measured cross-sections.- We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex and Idex, ANR, Region Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; the Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) an

    Measurement of the production cross-section of a single top quark in association with a W boson at 8 TeV with the ATLAS experiment

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    The cross-section for the production of a single top quark in association with a W boson in proton-proton collisions at s√=8TeV is measured. The dataset corresponds to an integrated luminosity of 20.3 fb−1, collected by the ATLAS detector in 2012 at the Large Hadron Collider at CERN. Events containing two leptons and one central b-jet are selected. The W t signal is separated from the backgrounds using boosted decision trees, each of which combines a number of discriminating variables into one classifier. Production of W t events is observed with a significance of 7.7σ. The cross-section is extracted in a profile likelihood fit to the classifier output distributions. The W t cross-section, inclusive of decay modes, is measured to be 23.0 ± 1.3(stat.)− 3.5+ 3.2(syst.)±1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |Vtb| of 1.01 ± 0.10 and a lower limit of 0.80 at the 95% confidence level. The cross-section for the production of a top quark and a W boson is also measured in a fiducial acceptance requiring two leptons with pT> 25 GeV and |η| 20 GeV and |η|  20 GeV, including both W t and top-quark pair events as signal. The measured value of the fiducial cross-section is 0.85 ± 0.01(stat.)− 0.07+ 0.07(syst.)±0.03(lumi.) pb

    Measurement of the total cross section from elastic scattering in pp collisions at s√ = 7 TeV with the ATLAS detector

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    A measurement of the total pp cross section at the LHC at √s = 7 TeV is presented. In a special run with high-β beam optics, an integrated luminosity of 80 µb−1 was accumulated in order to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable t. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the |t| range from 0.01 GeV2 to 0.1 GeV2 to extrapolate to |t| → 0, the total cross section, σtot(pp → X), is measured via the optical theorem to be: σtot(pp → X) = 95.35 ± 0.38 (stat.) ± 1.25 (exp.) ± 0.37 (extr.) mb, where the first error is statistical, the second accounts for all experimental systematic uncertainties and the\ud last is related to uncertainties in the extrapolation to |t| → 0. In addition, the slope of the elastic cross section at small |t| is determined to be B = 19.73 ± 0.14 (stat.) ± 0.26 (syst.) GeV−2

    Measurements of the Higgs boson production and decay rates and coupling strengths using pp collision data at √S=7 and 8 TeV in the ATLAS experiment

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    Combined analyses of the Higgs boson production and decay rates as well as its coupling strengths to vector bosons and fermions are presented. The combinations include the results of the analyses of the H -> gamma gamma, ZZ*, WW*, Z gamma, b (b) over bar, tau tau and mu mu decay modes, and the constraints on the associated production with a pair of top quarks and on the off-shell coupling strengths of the Higgs boson. The results are based on the LHC proton-proton collision datasets, with integrated luminosities of up to 4.7 fb(-1) at root s = 7 TeV and 20.3 fb(-1) at root s = 8 TeV, recorded by the ATLAS detector in 2011 and 2012. Combining all production modes and decay channels, the measured signal yield, normalised to the Standard Model expectation, is 1.18(-0.14)(+0.15). The observed Higgs boson production and decay rates are interpreted in a leading-order coupling framework, exploring a wide range of benchmark coupling models both with and without assumptions on the Higgs boson width and on the Standard Model particle content in loop processes. The data are found to be compatible with the Standard Model expectations for a Higgs boson at a mass of 125.36 GeV for all models considered
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