34 research outputs found

    Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

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    Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the hb(1P)h_b(1P) spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Measurement of the Top Pair Production Cross Section in the Dilepton Decay Channel in ppbar Collisions at sqrt s = 1.96 TeV

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    Submitted to Phys. Rev. DA measurement of the \ttbar production cross section in \ppbar collisions at s\sqrt{{\rm s}} = 1.96 TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II Detector. The result in a data sample corresponding to an integrated luminosity 2.8 fb1^{-1} is: \sigma_{\ttbar} = 6.27 ±\pm 0.73(stat) ±\pm 0.63(syst) ±\pm 0.39(lum) pb. for an assumed top mass of 175 GeV/c2c^{2}.A measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96  TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II detector. The result in a data sample corresponding to an integrated luminosity 2.8  fb-1 is σtt̅ =6.27±0.73(stat)±0.63(syst)±0.39(lum)  pb. for an assumed top mass of 175  GeV/c2.Peer reviewe

    Measurement of charged-particle event shape variables in inclusive root(s)=7 TeV proton-proton interactions with the ATLAS detector

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    The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data

    The current state of scaffolds for musculoskeletal regenerative applications

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    Musculoskeletal disease and injury are highly prevalent conditions that lead to many surgical procedures. Autologous tissue transfer, allograft transplantation and nontissue prosthetics are currently used for the surgical treatment of critical-sized defects. However, the field of tissue engineering is actively investigating tissue-replacement solutions, many of which involve 3D scaffolds. Scaffolds must provide a balance of shape, biomechanical function and biocompatibility in order to achieve tissue replacement success. Different tissues can have different requirements for success, which has led to the development of various materials with unique characteristics. Articular cartilage scaffolds have the most robust clinical experience, with many scaffolds, mostly constructed of natural materials, showing promise, but levels of success vary. Tendon scaffolds also have proven clinical applications, with human-dermis-derived scaffolds showing the most potential. Synthetic and naturally derived meniscus scaffolds have been investigated in few clinical studies, but the results are encouraging. Bone scaffolds are limited to amorphous pastes and putties, owing to difficulties achieving adequate vascularization and biomechanical optimization. The complex physiological function and vascular demands of skeletal muscle have limited the widespread clinical use of scaffolds for engineering this tissue. Continued progress in preclinical study, not only of scaffolds, but also of other facets of tissue engineering, should enable the successful translation of musculoskeletal tissue engineering solutions to the clinic

    Comparative epigenomics: an emerging field with breakthrough potential to understand evolution of epigenetic regulation

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