3,071 research outputs found

    Revisiting Charmless Hadronic B_{u,d} Decays in QCD Factorization

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    Within the framework of QCD factorization (QCDF), we consider two different types of power correction effects in order to resolve the CP puzzles and rate deficit problems with penguin-dominated two-body decays of B mesons and color-suppressed tree-dominated π0π0\pi^0\pi^0 and ρ0π0\rho^0\pi^0 modes: penguin annihilation and soft corrections to the color-suppressed tree amplitude. We emphasize that the electroweak penguin solution to the BKπB\to K\pi CP puzzle via New Physics is irrelevant for solving the CP and rate puzzles related to tree-dominated decays. While some channels e.g. Kπ+,Kρ0,π+π,ρ±πK^-\pi^+,K^-\rho^0,\pi^+\pi^-,\rho^\pm\pi^\mp need penguin annihilation to induce the correct magnitudes and signs for their CP violation, some other decays such as BKπ0,πη,KηB^-\to K^-\pi^0,\pi^-\eta, K^-\eta and Bˉ0Kˉ0η,π0π0\bar B^0\to \bar K^{*0}\eta,\pi^0\pi^0 require the presence of both power corrections to account for the measured CP asymmetries. In general, QCDF predictions for the branching fractions and direct CP asymmetries of BˉPP,VP,VV\bar B\to PP,VP,VV decays are in good agreement with experiment. The predictions of pQCD and soft-collinear effective theory are included for comparison.Comment: 51 pages, 1 figur

    Precision Measurement of KS Meson Lifetime with the KLOE detector

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    Using a large sample of pure, slow, short lived K0 mesons collected with KLOE detector at DaFne, we have measured the KS lifetime. From a fit to the proper time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This is the most precise measurement today in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the Ks.Comment: 5 pages, 7 figure

    Vacuum Properties of Mesons in a Linear Sigma Model with Vector Mesons and Global Chiral Invariance

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    We present a two-flavour linear sigma model with global chiral symmetry and vector and axial-vector mesons. We calculate pion-pion scattering lengths and the decay widths of scalar, vector, and axial-vector mesons. It is demonstrated that vector and axial-vector meson degrees of freedom play an important role in these low-energy processes and that a reasonable theoretical description requires globally chirally invariant terms other than the vector meson mass term. An important question for meson vacuum phenomenology is the quark content of the physical scalar f0(600) and a0(980) mesons. We investigate this question by assigning the quark-antiquark sigma and a0 states of our model with these physical mesons. We show via a detailed comparison with experimental data that this scenario can describe all vacuum properties studied here except for the decay width of the sigma, which turns out to be too small. We also study the alternative assignment f0(1370) and a0(1450) for the scalar mesons. In this case the decay width agrees with the experimental value, but the pion-pion scattering length a00a_{0}^{0} is too small. This indicates the necessity to extend our model by additional scalar degrees of freedom.Comment: 22 pages, 6 figure

    Measurement of the η3π0\eta\to 3\pi^{0} slope parameter α\alpha with the KLOE detector

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    We present a measurement of the slope parameter α\alpha for the η3π0\eta\to 3\pi^{0} decay, with the KLOE experiment at the DAΦ\PhiNE ϕ\phi-factory, based on a background free sample of \sim 17 millions η\eta mesons produced in ϕ\phi radiative decays. By fitting the event density in the Dalitz plot we determine α=0.0301±0.0035stat  0.0035+0.0022syst\alpha = -0.0301 \pm 0.0035\,stat\;_{-0.0035}^{+0.0022}\,syst\,. The result is in agreement with recent measurements from hadro- and photo-production experiments.Comment: 14 pages, 11 figure

    A Study of the Radiative Ke3 Decay and Search for Direct Photon Emission with the KLOE Detector

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    We present a measurement of the ratio R = \Gamma(\keg;\Estar>30\mev,\qstar>20^\circ)//\Gamma(\kegf)andafirstmeasurementofthedirectemissioncontributioninKLsemileptonicdecays.ThemeasurementisdoneattheDAFNEphifactoryselectingphi>KLKSdecayswiththeKLOEdetector.Weuse328pb1 and a first measurement of the direct emission contribution in KL semileptonic decays. The measurement is done at the DAFNE phi-factory selecting phi->KL KS decays with the KLOE detector. We use 328 pb^{-1} of data corresponding to about 3.5 million Ke3(g) events and about 9000 radiative events. Our result is R=(924 +/- 23(stat) +/-16(syst)10^{-5} for the branching ratio and X=-2.3 +/- 1.3(stat) +/- 1.4(syst) for the parameter describing direct emission.Comment: 8 pages, 7 figure

    Molecular targets of developmental exposure to bisphenol A in diabesity: a focus on endoderm-derived organs

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    Several studies associate foetal human exposure to bisphenol A (BPA) to metabolic/endocrine diseases, mainly diabesity. They describe the role of BPA in the disruption of pancreatic beta cell, adipocyte and hepatocyte functions. Indeed, the complexity of the diabesity phenotype is due to the involvement of different endoderm-derived organs, all targets of BPA. Here, we analyse this point delineating a picture of different mechanisms of BPA toxicity in endoderm-derived organs leading to diabesity. Moving from epidemiological data, we summarize the in vivo experimental data of the BPA effects on endoderm-derived organs (thyroid, pancreas, liver, gut, prostate and lung) after prenatal exposure. Mainly, we gather molecular data evidencing harmful effects at low-dose exposure, pointing to the risk to human health. Although the fragmentation of molecular data does not allow a clear conclusion to be drawn, the present work indicates that the developmental exposure to BPA represents a risk for endoderm-derived organs development as it deregulates the gene expression from the earliest developmental stages. A more systematic analysis of BPA impact on the transcriptomes of endoderm-derived organs is still missing. Here, we suggest in vitro toxicogenomics approaches as a tool for the identification of common mechanisms of BPA toxicity leading to the diabesity in organs having the same developmental origin

    Vector Correlators in Lattice QCD: methods and applications

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    We discuss the calculation of the leading hadronic vacuum polarization in lattice QCD. Exploiting the excellent quality of the compiled experimental data for the e^+e^- --> hadrons cross-section, we predict the outcome of large-volume lattice calculations at the physical pion mass, and design computational strategies for the lattice to have an impact on important phenomenological quantities such as the leading hadronic contribution to (g-2)mu and the running of the electromagnetic coupling constant. First, the R(s) ratio can be calculated directly on the lattice in the threshold region, and we provide the formulae to do so with twisted boundary conditions. Second, the current correlator projected onto zero spatial momentum, in a Euclidean time interval where it can be calculated accurately, provides a potentially critical test of the experimental R(s) ratio in the region that is most relevant for (g-2)mu. This observation can also be turned around: the vector correlator at intermediate distances can be used to determine the lattice spacing in fm, and we make a concrete proposal in this direction. Finally, we quantify the finite-size effects on the current correlator coming from low-energy two-pion states and provide a general parametrization of the vacuum polarization on the torus.Comment: 16 pages, 9 figure files; corrected a factor 2 in Eq. (7) over the published versio

    Measurement of the pseudoscalar mixing angle and η\eta^{\prime} gluonium content with KLOE detector

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    We have measured the ratio Rϕ=BR(ϕηγ)/BR(ϕηγ)R_{\phi}=BR(\phi \to \eta^{\prime} \gamma)/BR(\phi \to \eta \gamma) by looking for the radiative decays ϕηγ\phi \to \eta^{\prime} \gamma and ϕηγ\phi \to \eta \gamma in the final states π+π\pi^+\pi^- 7 γ\gamma's and 7 γ\gamma's respectively, in a sample of 1.3109\sim 1.3\cdot 10^{9} ϕ\phi mesons produced at the Frascati ϕ\phi-factory. We obtain Rϕ=(4.77±0.09stat±0.19sys)103R_{\phi}=(4.77\pm0.09_{stat}\pm0.19_{sys})\cdot 10^{-3} from which we derive BR(ϕηγ)=(6.20±0.11stat±0.25sys)105BR(\phi \to \eta^{\prime} \gamma)=(6.20\pm0.11_{stat}\pm0.25_{sys})\cdot 10^{-5}. In the hypothesis of no gluonium content we extract the pseudoscalar mixing angle in the quark-flavor basis ϕP=(41.4±0.3stat±0.7sys±0.6th)\phi_P=(41.4\pm0.3_{stat}\pm0.7_{sys}\pm0.6_{th})^{\circ}. Combining the value of RϕR_{\phi} with other constraints, we estimate the gluonium fractional content of η\eta^{\prime} meson as Z2=0.14±0.04Z^2 = 0.14\pm0.04 and the mixing angle ϕP=(39.7±0.7)\phi_P = (39.7\pm0.7)^{\circ}.Comment: 13 pages, 8 figure

    Dalitz plot analysis of e+ e- --> pi0 pi0 gamma events at SQRT(s) ~ M(phi) with the KLOE detector

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    We have studied the Dalitz plot of the e+ e- --> pi0 pi0 gamma events collected at SQRT(s) ~ M(phi) with the KLOE detector. In the dipion invariant mass (Mpp) region below 700 MeV, the process under study is dominated by the non-resonant process e+ e- --> omega pi0 with omega --> pi0 gamma whereas, for higher Mpp values, the radiative phi decay to the f0(980) is the dominant mechanism. Different theoretical models are used to fit the Dalitz plot, taking also into account a possible contribution of the sigma(600). For each model, we extract the f0(980) mass and its coupling to pipi, KKbar and to the phi.Comment: 21 pages, 15 figures, 5 tables, submitted to European Physics Journal

    Self-consistent simulation of plasma scenarios for ITER using a combination of 1.5D transport codes and free-boundary equilibrium codes

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    Self-consistent transport simulation of ITER scenarios is a very important tool for the exploration of the operational space and for scenario optimisation. It also provides an assessment of the compatibility of developed scenarios (which include fast transient events) with machine constraints, in particular with the poloidal field (PF) coil system, heating and current drive (H&CD), fuelling and particle and energy exhaust systems. This paper discusses results of predictive modelling of all reference ITER scenarios and variants using two suite of linked transport and equilibrium codes. The first suite consisting of the 1.5D core/2D SOL code JINTRAC [1] and the free boundary equilibrium evolution code CREATE-NL [2,3], was mainly used to simulate the inductive D-T reference Scenario-2 with fusion gain Q=10 and its variants in H, D and He (including ITER scenarios with reduced current and toroidal field). The second suite of codes was used mainly for the modelling of hybrid and steady state ITER scenarios. It combines the 1.5D core transport code CRONOS [4] and the free boundary equilibrium evolution code DINA-CH [5].Comment: 23 pages, 18 figure
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