Observation of a Near-Threshold Enhancement in the P-anti-p Mass Spectrum from Radiative J/psi --] Gamma-p-anti-p Decays
Title | Observation of a Near-Threshold Enhancement in the P-anti-p Mass Spectrum from Radiative J/psi --] Gamma-p-anti-p Decays PDF eBook |
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Release | 2003 |
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We observe a narrow enhancement near 2m[sub p] in the invariant mass spectrum of p[bar p] pairs from radiative J/[psi][yields][gamma]p[bar p] decays. No similar structure is seen in J/[psi][yields][pi][sup 0] p[bar p] decays. The results are based on an analysis of a 58 million event sample of J/[psi] decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m[sup p] at M= 1859[sub -10][sup+3] (stat)[sub -25][sup+5] (sys) MeV/c[sup 2] and the total width is[Lambda]
Near Threshold Enhancement of the P P-bar Mass Spectrum in J/Psi Decay
Title | Near Threshold Enhancement of the P P-bar Mass Spectrum in J/Psi Decay PDF eBook |
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Release | 2004 |
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We investigate the nature of the near-threshold enhancement in the p {bar p} invariant mass spectrum of the reaction J/[Psi] → [gamma] p {bar p} reported recently by the BES Collaboration. Using the Juelich N {bar N} model we show that the mass dependence of the p {bar p} spectrum close to the threshold can be reproduced by the S-wave p {bar p} final state interaction in the isospin I=1 state within the Watson-Migdal approach. However, because of our poor knowledge of the N {bar N} interaction near threshold and of the J/[Psi] → [gamma] p {bar p} reaction mechanism and in view of the controversial situation in the decay J/[Psi] → [pi]° p {bar p}, where no obvious signs of a p {bar p} final state interaction are seen, explanations other than final state interactions cannot be ruled out at the present stage.
High Energy Physics Index
Title | High Energy Physics Index PDF eBook |
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Pages | 786 |
Release | 1990 |
Genre | Nuclear physics |
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Energy Research Abstracts
Title | Energy Research Abstracts PDF eBook |
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Pages | 812 |
Release | 1986 |
Genre | Power resources |
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Analysis of the P P-bar Mass Spectrum in J/Psi
Title | Analysis of the P P-bar Mass Spectrum in J/Psi PDF eBook |
Author | A. W. Thomas |
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Release | 2005 |
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The near-threshold enhancement in the p p-bar invariant mass spectrum of the reaction J/Psi --> gamma p p-bar, observed in an experiment by the BES Collaboration, is analysed. It is shown, within the Watson-Migdal approach to final state interactions, that the mass dependence of the p p-bar spectrum close to the threshold can be reproduced by the S-wave p p-bar interaction of the Jülich N N-bar model in the isospin I=1 state. Difficulties in the consistent interpretation of the p invariant mass spectrum of the reaction J/Psi --> pi^0 p p-bar, where there are no obvious signs for a final state interaction, are discussed.
Nuclear Science Abstracts
Title | Nuclear Science Abstracts PDF eBook |
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Pages | 608 |
Release | 1976 |
Genre | Nuclear energy |
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Government Reports Announcements & Index
Title | Government Reports Announcements & Index PDF eBook |
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Pages | 1150 |
Release | 1986 |
Genre | Science |
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