557 research outputs found

    Implications of Recent Measurements of Hadronic Charmless B Decays

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    Implications of recent CLEO measurements of hadronic charmless B decays are discussed. (i) Employing the Bauer-Stech-Wirbel (BSW) model for form factors as a benchmark, the Bπ+πB\to\pi^+\pi^- data indicate that the form factor F0Bπ(0)F_0^{B\pi}(0) is smaller than that predicted by the BSW model, whereas the data of Bωπ,KηB\to\omega\pi, K^*\eta imply that the form factors A0Bω(0),A0BK(0)A_0^{B\omega}(0), A_0^{BK^*}(0) are greater than the BSW model's values. (ii) The tree-dominated modes Bπ+π,ρ0π±,ωπ±B\to\pi^+\pi^-, \rho^0\pi^\pm, \omega\pi^\pm imply that the effective number of colors N_c(LL) for (V-A)(V-A) operators is preferred to be smaller, while the current limit on BϕKB\to\phi K shows that N_c(LR)>3. The data of BKηB\to K\eta' and KηK^*\eta clearly indicate that Nc(LR)Nc(LL)N_c(LR)\gg N_c(LL). (iii) In order to understand the observed suppression of π+π\pi^+\pi^- and non-suppression of KπK\pi modes, both being governed by the form factor F0BπF_0^{B\pi}, the unitarity angle γ\gamma is preferred to be greater than 9090^\circ. By contrast, the new measurement of B±ρ0π±B^\pm\to\rho^0\pi^\pm no longer strongly favors cosγ<0\cos\gamma<0. (iv) The observed pattern K^-\pi^+\sim \ov K^0\pi^-\sim {2\over 3}K^-\pi^0 is consistent with the theoretical expectation: The constructive interference between electroweak and QCD penguin diagrams in the Kπ0K^-\pi^0 mode explains why {\cal B}(B^-\to K^-\pi^0)>{1\over 2}{\cal B}(\ov B^0\to K^-\pi^+). (v) The observation \nc(LL)<3<\nc(LR) and our preference for \nc(LL)\sim 2 and \nc(LR)\sim 6 are justified by a recent perturbative QCD calculation of hadronic rare B decays in the heavy quark limit.Comment: 21 pages; CLEO measurements of several charmless B decay modes are updated. Discussion of the unitarity angle gamma in the \rho\pi mode is revise

    Phenomenological Analysis of B->PP Decays with QCD Factorization

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    In this paper, we study nonleptonic charmless B decays to two light pseudoscalar mesons within the frame of QCD factorization, including the contributions from the chirally enhanced power corrections and weak annihilation. Predictions for the CP-averaged branching ratios and CP-violating asymmetries are given. Within the reasonable range of the parameters, we find that our predictions for the branching ratios of B -> PP are consistent with the present experimental data. But because of the logarithmic divergences at the endpoints in the hard spectator scatterings and weak annihilation, there are still large uncertainties in these predictions.Comment: 34 pages, 5 figures. to appear in PR

    Spatially Variable Reaction In The Formation Of Anodically Grown Porous Silicon Structures

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    In porous silicon formations there is an increase of dissolution rate at the fluorine-covered sites of the silicon surface due to the presence of excess electrons coming from oxidation of molecular hydrogen at the passivated (hydrogen-covered) sites. The dissolution rate increase in the presence of excess charge at the fluorine-covered sites is experimentally measured and a theoretical investigation is carried out by a semiempirical Hartree-Fock calculation. This spatially variable dissolution generates the porous silicon surface. © 1995 American Institute of Physics.78159059

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Forward jet production in deep inelastic ep scattering and low-x parton dynamics at HERA

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    Differential inclusive jet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector. Three phase-space regions have been selected in order to study parton dynamics where the effects of BFKL evolution might be present. The measurements have been compared to the predictions of leading-logarithm parton shower Monte Carlo models and fixed-order perturbative QCD calculations. In the forward region, QCD calculations at order alpha_s^1 underestimate the data up to an order of magnitude at low x. An improved description of the data in this region is obtained by including QCD corrections at order alpha_s^2, which account for the lowest-order t-channel gluon-exchange diagrams, highlighting the importance of such terms in parton dynamics at low x.Comment: 25 pages, 4 figure

    Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

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    We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

    Measurement of tau polarization in W->taunu decays with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

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    In this paper, a measurement of tau polarization in W->taunu decays is presented. It is measured from the energies of the decay products in hadronic tau decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb^-1, were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the tau polarization is Ptau = -1.06 +/- 0.04 (stat) + 0.05 (syst) - 0.07 (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95% CL interval [-1,-0.91]. Measurements of tau polarization have not previously been made at hadron colliders.Comment: 10 pages plus author list (25 pages total), 4 figures, 4 tables, revised author list, matches published EPJC versio

    Interpretação dos Efeitos de Tempo Nublado e Chuvoso Sobre a Radiação Solar em Belém/PA Para Uso em Sistemas Fotovoltaicos

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    Resumo Neste trabalho foi desenvolvido um software que prediz a variação de direção de incidência dos raios solares ao longo do ano e dos horários do dia, o qual é utilizado para estimar a melhor orientação na instalação de painéis fotovoltaicos na cidade de Belém/PA. A utilização do potencial de radiação solar em Belém poderá ser transformada em energia útil. Todavia, a eficiência de conversão solar no local também depende das condições atmosféricas que interferem nesse aproveitamento. Portanto, também foram avaliados os efeitos de tempo nublado e chuvoso através da precipitação e da comparação entre a radiação simulada (para céu limpo) e a radiação medida disponibilizada pelo INMET, que estima a radiação real, o que leva em conta efeitos que afetam a radiação, como céu nublado. Portanto, a partir da análise conjunta da radiação solar incidente na superfície com o índice pluviométrico, foi avaliada a potencialidade energética solar do local durante o ano, onde foi possível perceber uma correlação do período de menor precipitação com a elevação no índice de radiação medido, favorecendo nesse período um melhor rendimento energético para o painel fotovoltaico.</jats:p

    Knowledge, skills, and barriers to management of faecal incontinence in Australian primary care: a cross-sectional study

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    Published: 21 April 2021Background: GPs play an important role in the diagnosis and management of patients with faecal incontinence (FI). However, their confidence and ability in this role are unknown. Aim: This study aimed to investigate the knowledge, skills, and confidence of GPs to manage FI in primary care, and identify barriers to optimal management. Design & setting: A cross-sectional study using self-administered questionnaires of GPs attending health education seminars, which took place across Australian capital cities. Method: Main outcome measures included: (i) clinical exposure to and previous training in FI; (ii) knowledge and skills in screening, diagnosing, and managing FI; and (iii) barriers and facilitators to optimising care. Associations between demographics, training and knowledge and skills were assessed. Results: Some 1285 of 1469 GPs (87.5%) participated (mean 47.7 years [standard deviation {SD} 11.3]). The vast majority reported poor clinical exposure to (88.5%) and training in FI management (91.3%). Subjectively, 69.7% rated their knowledge and skills in screening, assessing, and treating FI as suboptimal. The most commonly reported barrier to FI care was ‘insufficient skills’ (56.1%); facilitators were improved referral pathways (84.6%) and increased training (67.9%). GPs with more training had better knowledge (odds ratio [OR] = 24.62, 95% confidence interval [CI] = 13.32 to 45.51) and skills (OR = 13.87, 95% CI = 7.94 to 24.24) in managing FI. Conclusion: Clinical exposure to and training in FI among GPs was poor. Accordingly, knowledge, skills, and confidence to manage FI was suboptimal. GPs recognise the importance of FI and that increased training and/or education and formalisation of referral pathways may improve the care of patients with FI in primary care.Kheng-Seong Ng, Deanne S Soares, Sireesha Koneru, Ramesh Manocha, Marc Antony Gladma
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