47,487 research outputs found

    The X(3872) at the Tevatron

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    I report results on the X(3872) from the Tevatron. Mass and other properties have been studied, with a focus on new results on the dipion mass spectrum in X -> J/PsiPi^+Pi^- decays. Dipions favor interpreting the decay as J/PsiRho, implying even C-parity for the X. Modeling uncertainties do not allow distinguishing between S- and P-wave decays of the J/PsiRho mode. Effects of Rho-Omega interference in X decay are also introduced.Comment: Contribution to PANIC05, Santa Fe, 24-28 October 2005 (4 pages, 6 plots

    Microscopic Approach to Nucleon Spectra in Hypernuclear Non-Mesonic Weak Decay

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    A consistent microscopic diagrammatic approach is applied for the first time to the calculation of the nucleon emission spectra in the non-mesonic weak decay of Lambda-hypernuclei. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one--meson exchange weak transition potential and a Bonn nucleon-nucleon strong potential. Ground state correlations and final state interactions, at second order in the nucleon--nucleon interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Single and double--coincidence nucleon spectra are predicted for 12_Lambda^C and compared with recent KEK and FINUDA data. The key role played by quantum interference terms allows us to improve the predictions obtained with intranuclear cascade codes. Discrepancies with data remain for proton emission.Comment: 11 pages, 6 figures, 2 tables. To be published in Physics Letters

    The Translation Evidence Mechanism. The Compact between Researcher and Clinician.

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    Currently, best evidence is a concentrated effort by researchers. Researchers produce information and expect that clinicians will implement their advances in improving patient care. However, difficulties exist in maximizing cooperation and coordination between the producers, facilitators, and users (patients) of best evidence outcomes. The Translational Evidence Mechanism is introduced to overcome these difficulties by forming a compact between researcher, clinician and patient. With this compact, best evidence may become an integral part of private practice when uncertainties arise in patient health status, treatments, and therapies. The mechanism is composed of an organization, central database, and decision algorithm. Communication between the translational evidence organization, clinicians and patients is through the electronic chart. Through the chart, clinical inquiries are made, patient data from provider assessments and practice cost schedules are collected and encrypted (HIPAA standards), then inputted into the central database. Outputs are made within a timeframe suitable to private practice and patient flow. The output consists of a clinical practice guideline that responds to the clinical inquiry with decision, utility and cost data (based on the "average patient") for shared decision-making within informed consent. This shared decision-making allows for patients to "game" treatment scenarios using personal choice inputs. Accompanying the clinical practice guideline is a decision analysis that explains the optimized clinical decision. The resultant clinical decision is returned to the central database using the clinical practice guideline. The result is subsequently used to update current best evidence, indicate the need for new evidence, and analyze the changes made in best evidence implementation. When updates in knowledge occur, these are transmitted to the provider as alerts or flags through patient charts and other communication modalities

    On the role of ground state correlations in hypernuclear non-mesonic weak decay

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    The contribution of ground state correlations (GSC) to the non--mesonic weak decay of Λ12^{12}_\LambdaC and other medium to heavy hypernuclei is studied within a nuclear matter formalism implemented in a local density approximation. We adopt a weak transition potential including the exchange of the complete octets of pseudoscalar and vector mesons as well as a residual strong interaction modeled on the Bonn potential. Leading GSC contributions, at first order in the residual strong interaction, are introduced on the same footing for all isospin channels of one-- and two--nucleon induced decays. Together with fermion antisymmetrization, GSC turn out to be important for an accurate determination of the decay widths. Besides opening the two--nucleon stimulated decay channels, for Λ12^{12}_\LambdaC GSC are responsible for 14% of the rate Γ1\Gamma_1 while increasing the Γn/Γp\Gamma_{n}/\Gamma_{p} ratio by 4%. Our final results for Λ12^{12}_\LambdaC are: ΓNM=0.98\Gamma_{\rm NM}=0.98, Γn/Γp=0.34\Gamma_{n}/\Gamma_{p}=0.34 and Γ2/ΓNM=0.26\Gamma_2/\Gamma_{\rm NM}=0.26. The saturation property of ΓNM\Gamma_{\rm NM} with increasing hypernuclear mass number is clearly observed. The agreement with data of our predictions for ΓNM\Gamma_{\rm NM}, Γn/Γp\Gamma_n/\Gamma_p and Γ2\Gamma_2 is rather good.Comment: 32 pages, 9 figure