14 research outputs found

    On the measured lifetime of light hypernuclei 3 Λ H and 4 Λ H

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    A statistical combination of the experimental lifetime estimations available in the literatures is performed for 3 Λ H and 4 Λ H, including several recent measurements. The combined average values of the lifetime for 3 Λ H and 4 Λ H are respectively <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow><mn>216</mn></mrow><mrow><mo>−</mo><mn>16</mn></mrow><mrow><mo>+</mo><mn>19</mn></mrow></msubsup><mtext> </mtext><mtext>ps</mtext></math> and <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow><mn>192</mn></mrow><mrow><mo>−</mo><mn>18</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup><mtext> </mtext><mtext>ps</mtext></math> with a reduced <math altimg="si3.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msup><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msup></math> of 0.89 and 0.48. A new insight into the lifetime estimation of the HypHI Phase 0 experiment by a Bayesian approach is also presented. In this approach, several different prior distributions including the combination of previous lifetime data and a Jeffrey prior are used. The principal mode and the smallest credible interval at 68% of the posterior distribution, given by the prior belief of the previous measurements, are <math altimg="si4.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow><mn>217</mn></mrow><mrow><mo>−</mo><mn>16</mn></mrow><mrow><mo>+</mo><mn>19</mn></mrow></msubsup><mtext> </mtext><mtext>ps</mtext></math> and <math altimg="si5.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow><mn>194</mn></mrow><mrow><mo>−</mo><mn>18</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup><mtext> </mtext><mtext>ps</mtext></math> respectively for 3 Λ H and 4 Λ H. The two employed approaches have revealed that the lifetime of hypernuclei 3 Λ H and 4 Λ H can be shorter than the Λ –hyperon lifetime

    Hypernuclear production cross section in the reaction of 6 Li + 12 C at 2A GeV

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    Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI Collaboration exploiting the reaction of 6 Li + 12 C at 2A GeV or sNN=2.70 GeV . A production cross section of 3.9±1.4 μb for 3 Λ H and of 3.1±1.0 μb for 4 Λ H respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7±0.8 mb . A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3 Λ H/ 4 Λ H, 3 Λ H/Λ and 4 Λ H/Λ were included in the inference procedure. The strangeness population factors S 3 and S 4 of 3 Λ H and 4 Λ H respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3 Λ H, and 4 Λ H together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported

    Technical Design Report for PANDA Electromagnetic Calorimeter (EMC)

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    This document presents the technical layout and the envisaged performance of the Electromagnetic Calorimeter (EMC) for the PANDA target spectrometer. The EMC has been designed to meet the physics goals of the PANDA experiment, which is being developed for the Facility for Antiproton and Ion Research (FAIR) at Darmstadt, Germany. The performance figures are based on extensive prototype tests and radiation hardness studies. The document shows that the EMC is ready for construction up to the front-end electronics interface

    Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons

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    To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy thereby allowing high-precision tests of the strong interaction. The proposed PANDA detector is a state-of-the art internal target detector at the HESR at FAIR allowing the detection and identification of neutral and charged particles generated within the relevant angular and energy range. This report presents a summary of the physics accessible at PANDA and what performance can be expected

    "Bare Cross Section" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Bare cross section σbare(e+e−→π+π−(γFSR))\sigma^\mathrm{bare}(e^+e^-\to\pi^+\pi^-(\gamma_\mathrm{FSR})) of the process e+e−→π+π−e^+e^-\to\pi^+\pi^- measured using the initial state radiation method. The data is corrected concerning final state radiation and vacuum polarization effects. The final state radiation is added using the Schwinger term at born level

    "Covariance Matrix of the Pion Form Factor" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Statistical covariance matrix of the pion form factor ∣Fπ∣2|F_\pi|^2

    "Table 1" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Results of the BESIII measurement of the cross section σπ+π−(γFSR)bare≡σbare(e+e−→π+π−(γFSR))\sigma^{\rm bare}_{\pi^+\pi^-(\gamma_{\rm FSR})} \equiv \sigma^{\rm bare}(e^+e^-\rightarrow\pi^+\pi^-(\gamma_{\rm FSR})) and the squared pion form factor ∣Fπ∣2|F_\pi|^2. The errors are statistical only. The value of s′\sqrt{s'} represents the bin center. The 0.9%\% systematic uncertainty is fully correlated between any two bins

    "Pion Form Factor" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Pion form factor ∣Fπ∣2|F_\pi|^2 measured using the initial state radiation method. The data is corrected concerning vacuum polarization effects

    "Table 1" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Results for the bare cross section σπ+π−bare\sigma^\text{bare}_{\pi^+\pi^-} and the pion form factor together with their statistical uncertainties. The systematical uncertainties are given by 0.9% (see arXiv:1507.08188)

    "Bare Cross Section" of "Measurement of the e+e−→π+π−\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation"

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    Bare cross section σbare(e+e−→π+π−(γFSR))\sigma^\mathrm{bare}(e^+e^-\to\pi^+\pi^-(\gamma_\mathrm{FSR})) of the process e+e−→π+π−e^+e^-\to\pi^+\pi^- measured using the initial state radiation method. The data is corrected concerning final state radiation and vacuum polarization effects. The final state radiation is added using the Schwinger term at born level
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