1. ee→J/ψ X(1835) & ee→J/ψρ(φ)
Peking University
Wang Jian
April

2. pp found by BES 1

3. X(1835) found by BES
eta’ excited state? glueball state? Or others? 2

4. KEKB/Belle
=10.58GeV c s d u 3

5. ee→J/ψ cc
Problem 方 案 一 4

6. ee→J/ψ cc vs. ee→J/ψ glueball
Problem 方 案 二 5

7. Searching for X(1835) in recoil mass against J/ψ6

8. Background study
Red histogram: continuum background (u,d,s,c) MC generated using EvtGen; Blue one: just u,d,s continuum MC data.
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). 7

9. Fitting/Result 8

10. e+e-J/ψ()
Introduction 1 2 3 9

11. e+e-VV----VMD model calculation
M. Davier et al, hep-ph/
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.
The value obtained for e+e-J/psi J/psi differs somewhat from the estimate given by
vs. 10

12. Selection criteria
Two photon processes was removed
under * 11

13. Some plots
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/ 12

14. Fitting/results
scaled 13

15. Fitting/results 14

16. Production anglue and helicity studyMC MC
Consistent with theoritic prediction using Two-Virtual Photon Annihilation very well. 15

17. 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():
An upper limit for e+e-J/ψ is set to be 2.4fb at 90%.
which is consistent with the theoritic pridiction:
hep-ph/ 16