1,147 research outputs found

    Análise do perfil químico cuticular de fêmeas e imaturos de Latrodectus geometricus (Araneae: Theridiidae) usando GC×GC/qMS

    Get PDF
    Communication in spiders can occur by several mechanisms, such as chemical cues and the cuticular hydrocarbons (CHCs) play an important role in intraspecific recognition. Several techniques have been used to evaluate CHCs in spiders, such as Gas Chromatography with Flame Ionization Detection, Gas Chromatography coupled with Mass Spectrometric detection and recently Fourier Transformed Infrared Photoacoustic Spectroscopy. In this study, rapid-scanning two-dimensional gas chromatography with quadrupole mass spectrometry (GC×GC/qMS) was employed to assess the CHCs of L. geometricus females and juveniles of different ages. The results demonstrate that there is variation in CHCs of different body parts of females, with abdomen presenting greater number of compounds, as well as between adults and juveniles. Branched alkanes represented the majority of compounds in all samples, followed by linear alkanes, and alkenes were only present in adult’s abdomen and cephalothorax. The compounds 10-methyloctacosaneand 14-methyloctacosane; and 10-methyltriacontane and 14-methyltriacontane showed the same retention time in the 1D and were separated in the 2D. According to the results, rapid-scanning GC×GC/qMS can be considered a reliable technique to assess CHCs since it was possible to identify the spider’s cuticular compounds, and detect and separate two cases of chromatographic coelution.A comunicação em aranhas pode ocorrer por vários mecanismos, especialmente sinais químicos, e os hidrocarbonetos cuticulares (CHCs) desempenham papel fundamental no reconhecimento intraespecífico. Várias técnicas têm sido utilizadas para avaliar os CHCs em aranhas. Aqui, a Cromatografia bidimensional de varredura rápida com espectrometria de massa quadrupolo foi empregada para avaliar o perfil de CHCs de fêmeas de L. geometricus e imaturos de diferentes idades. Amostras do cefalotórax, abdome e pernas de fêmeas foram usadas para avaliar se há variação em CHCs entre as partes. Para avaliar se há variação entre idades, foram usados imaturos de 5 e 20 dias pós-emergência. Os resultados demonstram que há variação em CHCs de diferentes partes do corpo, com abdome apresentando o maior número de compostos, bem como entre adultos e imaturos. Alcanos ramificados representaram a maioria dos compostos em todas as amostras, seguidos por alcanos lineares. Alcenos só estavam presentes no abdome e cefalotórax das adultas. Os compostos 10-metiloctacosano e 14-metiloctacosano; e 10-metiltriacontano e 14-metiltriacontano tiveram o mesmo tempo de retenção em 1D e foram separados em 2D. De acordo com os resultados, a técnica pode ser considerada confiável, já que foi possível identificar os CHCs da aranha, e detectar e separar dois casos de coeluição cromatográfica

    Observation of J/ψpJ/\psi p resonances consistent with pentaquark states in Λb0J/ψKp{\Lambda_b^0\to J/\psi K^-p} decays

    Get PDF
    Observations of exotic structures in the J/ψpJ/\psi p channel, that we refer to as pentaquark-charmonium states, in Λb0J/ψKp\Lambda_b^0\to J/\psi K^- p decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis is performed on the three-body final-state that reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψpJ/\psi p mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380±8±294380\pm 8\pm 29 MeV and a width of 205±18±86205\pm 18\pm 86 MeV, while the second is narrower, with a mass of 4449.8±1.7±2.54449.8\pm 1.7\pm 2.5 MeV and a width of 39±5±1939\pm 5\pm 19 MeV. The preferred JPJ^P assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after referee's comments, now 19 figure

    Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

    Get PDF
    Angular correlations in B+X(3872)K+B^+\to X(3872) K^+ decays, with X(3872)ρ0J/ψX(3872)\to \rho^0 J/\psi, ρ0π+π\rho^0\to\pi^+\pi^- and J/ψμ+μJ/\psi \to\mu^+\mu^-, are used to measure orbital angular momentum contributions and to determine the JPCJ^{PC} value of the X(3872)X(3872) meson. The data correspond to an integrated luminosity of 3.0 fb1^{-1} of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be JPC=1++J^{PC}=1^{++}. The X(3872)X(3872) is found to decay predominantly through S wave and an upper limit of 4%4\% at 95%95\% C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

    Precise measurements of the properties of the B-1(5721)(0,+) and B-2*(5747)(0,+) states and observation of B-+,B-0 pi(-,+) mass structures

    Get PDF
    Invariant mass distributions of B+π− and B0π+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb−1 of pp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B1(5721)0,+ and B2(5747)0,+ states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850-6000 MeV in both B+π− and B0π+ combinations. The structures are consistent with the presence of four excited B mesons, labelled BJ (5840)0,+ and BJ (5960)0,+, whose masses and widths are obtained under different hypotheses for their quantum numbers

    Report from Working Group 3: Beyond the standard model physics at the HL-LHC and HE-LHC

    Get PDF
    This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as 33 ab1^{-1} of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as 1515 ab1^{-1} of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by 2050%20-50\% on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will, generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics

    Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

    Get PDF
    Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated tt\mathrm{t}\overline{\mathrm{t}} events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

    Search for heavy resonances decaying to a top quark and a bottom quark in the lepton+jets final state in proton–proton collisions at 13 TeV

    Get PDF
    info:eu-repo/semantics/publishe

    Evidence for the Higgs boson decay to a bottom quark–antiquark pair

    Get PDF
    info:eu-repo/semantics/publishe
    corecore