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

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

Searching for X(1835) in recoil mass against J/ψ 6

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

Fitting/Result 8

e+e-J/ψ() Introduction 1 2 3 9

e+e-VV----VMD model calculation M. Davier et al, hep-ph/0606155 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

Selection criteria Two photon processes was removed under * 11

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/0606155. 12

Fitting/results scaled 13

Fitting/results 14

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

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/0606155 16