ee→J/ψ X(1835) & ee→J/ψρ(φ)

Peking University

Wang Jian

April 19. 2010

pp found by BES

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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

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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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