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ee→J/ ψ X(1835) & ee→J/ ψρ ( φ ). Peking University Wang Jian April 19. 2010. pp found by BES. 1. X(1835) found by BES. eta’ excited state? glueball state? Or others?. 2. KEKB/Belle. =10.58GeV. c s d u. 3. ee→J/ ψ cc. Problem. 方 案 一. 4. - PowerPoint PPT Presentation
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ee→J/ψ X(1835) & ee→J/ψρ(φ)
Peking University
Wang Jian
April 19. 2010
pp found by BES
1
X(1835) found by BES
eta’ excited state?glueball state?Or others?
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KEKB/Belle=10.58GeV
csdu
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ee→J/ψ ccProblem
方案一
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ee→J/ψ cc vs. ee→J/ψ glueballProblem
方案二
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Searching for X(1835) in recoil mass against J/ψ
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Background study
• Combinatorial di-muon events fallen in J/psi mass window(green histogram);
• Peaking background: 1.Prompt J/psi a. b. 2.Non-prompt J/psi(negligible from a MC test on ee-> Ψ’γ/ee->Y(4360) γ).
Red histogram: continuum background (u,d,s,c) MC generated using EvtGen;Blue one: just u,d,s continuum MC data.
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Fitting/Result
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Introduction1
2 3
e+e-J/ψ()
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e+e-VV----VMD model calculation
• Assuming the e+e− → ** process followed by conversion of * into V1 and V2, with effective coupling e/f1 and e/f2 . The cross section in c.m. frame can be written as:
• Obtain effective coupling through meson’s leptonic width:
• Calculation with this simple VMD model agree with the measurements of e+e-0/. More calculations based on VMD are summarized in the previous slide.
M. Davier et al, hep-ph/0606155
• The value obtained for e+e-J/psi J/psi differs somewhat from the estimate given by
vs.
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Selection criteria
Two photon processes was removed under
*
*
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• Green histograms are MC data scaled to 10.16fb and 1.46fb for e+e-J/ψ and e+e-J/ψ respectively, calculated in hep-ph/0606155.
Some plots
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Fitting/results
scaled
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Fitting/results
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Production anglue and helicity study
MC
MC
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Consistent with theoritic prediction using Two-Virtual Photon Annihilation very well.
Summary•Set an upper limit for ee→J/ψ X(1835) to be 0.9 fb at 90% CL.
•First mesurement for decay e+e-J/ψ():
which is consistent with the theoritic pridiction: hep-ph/0606155
An upper limit for e+e-J/ψ is set to be 2.4fb at 90%.
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