170 likes | 356 Views
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.
E N D
ee→J/ψ X(1835) & ee→J/ψρ(φ) Peking University Wang Jian April 19. 2010
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
Backgroundstudy • 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. 7
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
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%. hep-ph/0606155 which is consistent with the theoritic pridiction: 16