1. e+e-  J/y (cc) at s≈10.6 GeV_
e+e-  J/y (cc) at s≈10.6 GeV
QWG 2004 Worksop
IHEP Beijing
S.L. Olsen (U of Hawai’i)
Representing elle

2. Pinch-hitting for (visaless) Henryk Palka
INS Krakow

3. 2001: Belle & BaBar report on e+e-J/y X @s≈10.6 GeV
BaBar: PRL 87,
Belle: PRL 88,052001
L =21 fb-1
L =32 fb-1
ZZZZ
PJ/y(GeV/c)
PJ/y(GeV/c)

4. 2002: look in detail at MX
Pasha Pakhlov
ITEP-Moscow

5. Eureka!

6. 4 surprizes!
select J/yl+l-
+ >2 chrgd trks
no signal for MX<Mhc
clear hc, cc0 & hc’ signals
s(e+e-  J/y hc) > 10x theory
s(e+e-  J/y cc
s(e+e-  J/y all)
L=101 fb-1 ‘ hc hc
cc0 * **
=0.6 ± 0.2
*E.Braaten & J. Lee PRD 67, (2003)
“no unknown non-perturbative parameters”
K.Abe et al (Belle)
PRL 89,
**NRQCD predicts this to be ≈ 0.1

7. Possibilities “hc” peak has some contamination from e+e- ggJ/yJ/y
Bodwin, Lee & Braaten PRL 90,
The “hc” peak has some
glueball content (in addition
to charmonium)
Brodsky, Goldhaber & Lee PRL 91,
Dulat, Hagiwara & Lin hep-ph/

8. 2003 Infer DMrecoil(J/y)<3 MeV
Check recoil mass scale using e+e- g y(2S)
p+p- J/y
Mx (p+p-J/y)
Infer DMrecoil(J/y)<3 MeV

9. 2003:
Fit for J/y J/y (+ other) components hc ‘
L=155 fb-1
cc0 hc

10. No significant contamination from e+e-  gg  J/y J/y

11. Angular distributions are consistent with charmonium expectations
2003:
Angular distributions are consistent
with charmonium expectations l+
J/y
qhel
qprod X
J/y e- e+
glueball prediction:
cos2q
cos2q

12. Try to reconstruct hcKSKp, or 4K
Find 3 events
expect 2.6
MC  No ISR b  ISR >10MeV

13. “hc” peak looks like an hc & not like a glueball

14. 2003: look at e+e- y(2S) X hc ‘
cc0 hc
similar pattern

15. Theory (Braaten & Lee) : <2.3±1 fb
Cross sections
Theory (Braaten & Lee) : <2.3±1 fb

16. 2004: more data, more surprizes!
L= 287 fb -1

17. Summary Continuum e+e-  J/y X is full of surprizes
s(e+e- J/y hc) > 10 x theory
e+e-  gg  J/y J/y contamination is small
No evidence for e+e- J/y glueball
e+e-J/y cc/e+e-J/y X ≈ 0.6 ± 0.2
many times expecations
evidence for a new charmonium-like state
Mx continuum turns on near Mx≈Mhc

18. Belle’s experience
more data
more surprizes

19. Backup Slides

20. Look at e+e-J/y D(D(*))
Reconstruct a J/y & a D
use D0K-p+ & D+K-p+p+
Determine recoil mass

21. Look at M(DD(*)) cc0 DD* ‘ hc DD “ 9.9 ± 3.3 evts (4.5 s) DD* DD
3940 MeV
9.9 ± 3.3 evts
(4.5 s)
DD*
cc0 DD* ‘ DD
4.1 ± 2.2 evts
(2.1 s)
hc DD “

22. Select regions of cosqprod(hel) and then fit Mx distributions

23. - 2004 ‘ non-zero continuum below DD threshold 4th peak!! 2002 2003
L=101 fb-1
L=155 fb-1 -
e+e-J/y (cc) > e+e-J/y glue
s(e+e-J/y hc) 10x theory
evidence for hc’
ggJ/y J/y negligible
confirm hc’
2004
287 fb -1 ‘ hc hc
cc0
non-zero continuum
below DD threshold
4th peak!!