1. Non-standard mesons in BES III?
Stephen L. Olsen, Univ of Hawai’i
BES annual mtg Shi-dou, May 30-June 2, 2005

2. non-standard hadrons non-qqq baryons or non-qq mesons: s Pentaquarks:
e.g. an S=+1 baryon
Glueballs:
gluon-gluon color singlet states
Multi-quark mesons:
qq-gluon hybrid mesons d u u d s u c u c c c

3. mesons with “hidden charm” are a good place to looku c c c u c
standard cc mesons are:
best understood theoretically
decay properties well known
narrow & non overlapping
concentrate on charmonium-like particles that don’t match expected properties

4. What about the y(4.03) ? Conventional wisdom: y(4.03)= y(3S)
D*D* DD
DD*
Ecm(GeV/c)

5. D momentum spectra @ 4.03GeV
DD*
DD*
D*D*
Ling-jun Pan,
BES data DD
D*D* DD D+ D0
Why is G(y(4.03) D*D*) so huge?
DD/DD*/D*D*: 1/20/ phase-space
Charmonium S-wave: 1/4/ removed
D-wave: 1/1/4

6. Suggestions D* D* y(4.03)=D*D* molecule? a cc-gluon hybrid? c c p,s u
PRL 38, 317
p,s D* u u
a cc-gluon
hybrid?
PLB 366, 323 c c

7. hadronic molecules a new spectroscopy?

8. DeRujula, Georgi,Glashow, PRL 38, 317 (1977)
Many possibilities
For BESIII

9. cc-gluon hybrids another new spectroscopy?

10. Hybrid states More possibilities For BESIII “normal” cc mesons DD
mixes with
y(4.03)?? DD
cc gluon
hybrids
More possibilities
For BESIII

11. Belle has candidates for each
DD* molecular state: X(3872)
S.-K. Choi et al PRL 91,
cc-gluon hybrid: Y(3940)
S.-K/ Choi et al, PRL 94,

12. The X(3872) seen in: C=+ y’ Ispin is violated XgJ/y Xp+p-J/y
Xp+p-p0J/y
Xp+p-J/y y’
X(3872)
M(p+p-p0) MeV
M(gJ/y)
M(ppJ/y) –M(J/y)
Ispin is
violated
& XD0D0p0
M(D0D0p0) MeV

13. X(3872) = D0D*0 bound state? JPC = 1++ (favored by DD* models)
M ≈ mD0 + mD0*
Maximal isospin violation is natural (& was predicted):
|I=1; Iz= 0> =1/2(|D+D*->+ |D0D*0>)
|I=0; Iz= 0> =1/2(|D+D*-> - |D0D*0>)
 |D0D*0> = 1/2(|10> - |00>)
G(XgJ/y) < G(XppJ/y)
Tornqvist PLB 590, 209 (2004)
Equal mixture of I=1 & I =0
Swanson PLB 588, 189 (2004)
Swanson PLB 598, 197 (2004)

14. X(3872) conclusion see hep-ex/0505037 & 0505038
JPC = 1++
cc content is small
matches all(?) expectations for a D0D*0 bound state C C c c D*
p,s D* u u

15. BES has a candidate too! from Ling-Jun’s y(4.03)  DX study
Study this

16. Look at DD* region
D*+D+p0
D*+D+p0
D*+D+g
D*+D+p+
D*0D0p0
D*0D0g

17. Fits to momentum spectra are poor
D* Br’s fixed at
PDG values
c2/dof = 129/78
CL:0.028% D+
Too few
daughters D0
L.J. Pan, PhD thesis

18. Add some y(4.03)pŨ; ŨDD MŨ~3860 MeV GŨ<12 MeV c2/dof = 100/73
CL: 5%
Bry?p=16%
ŨDD
MŨ~3860 MeV
GŨ<12 MeV
ŨDD
L.J. Pan, PhD thesis

19. DeRujula, Georgi,Glashow, PRL 38, 317 (1977)
Ũ(3860)
X(3872)??
ŨDD allowed

20. Bf(BKY)Bf(YwJ/y)=7.1±1.3±3.1x10-5
cc gluon candidate from Belle: Y(3940)
BK wJ/y
“Y(3940)”
M≈3940 ± 11 MeV
G≈ 92 ± 24 MeV
Mbc
Mbc
Mbc
Bf(BKY)Bf(YwJ/y)=7.1±1.3±3.1x10-5
S.K. Choi et al, PRL 94,

21. Y(3940): What is it? Some kind of w-J/y threshold interaction?
Brambilla et al (QWG) hep-ph/
Eichten, Lane & Quigg PRD 64,
Barnes, Godfrey & Swanson hep-ph/
Charmonium?
Conventional wisdom: wJ/y should not be a discovery mode for a cc state with mass above DD & DD* threshold!
Some kind of w-J/y threshold interaction?
the J/y is not surrounded by brown muck; can it act like an ordinary hadron? w
J/y

22. Y(3940): What is it (cont’d)?
another 4-quark state?
M ≈ 2mDs
not seen in YhJ/y
(h contains ss)
width too large??
no p exchange for DSDS s s c ??
PRL 93,
M(h J/y)

23. Y(3940): What is it (cont’d) ?
cc-gluon hybrid?
predicted by QCD,
decays to DD and DD* are suppressed
(“open-charm” thresh = mD + m D** = 4.3 GeV)
large hadron+J/y widths are predicted
masses expected to be 4.3 ~ 4.4 GeV (higher than what we see)
Horn & Mandula PRD (1978)
Isgur et al PRL 54, 869 (1995)
Close PLB 342, 369
McNiele et al PRD 65
094505 c c

24. “open charm” threshold for hybrids is here
DD*
D*D* DD
Ecm(GeV/c)
Hybrid states in this mass range may decay to x J/y (or hc, cc,…)
x=light hadrons

25. Search strategies for BESIII
DD(*) molecular states
y(4.03)p(g) + Ũ
Study DD & DD* y(4.03) (& y(4.16)??)
light cc gluon hybrids
y(4.03) g + ccg hybrid
Study J/y (cc, hc) + light hadons y(4030), y(4160) (& y(4415)??)

26. Rate estimates (DD(*) molecules) (1yr = 6fb-1)
L.-J. Pan’s thesis:
~16% of y(4.03)DDp
yield is via:
y(4.03)p Ũ(3860)
DD
If DD recon effic ~0.1%
Expect: 103 Ũ(3860)DD/yr
including
D Br’s

27. Rate estimates (cc-gluon hybrids)
y(4.03) g + (cc gluon hybrid)
assume:
G(y(4.03)g wJ/y)~G(y(3.77)ppJ/y)~100keV
Recon effic wJ/y ~ 1%
or gg, or p
G(y(4.03)g wJ/y)
G(y(3.77)ppJ/y)
N(y(4.03)gwJ/y) ~ 103/yr x
Can search in many other channels:
y(4.03)g (gg,p) + ppJ/y ( hJ/y, ppcc, …)

28. 4.03 (& 4.16 GeV + higher?) may be very interesting.
Summary
BESIII runs at
4.03 (& 4.16 GeV + higher?) may be very interesting.

29. 謝謝

30. Announcement

31. 謝謝

32. Backup slides

33. Look at events where 2 D mesons are found
????
Expect ~ 10 ??(3860)DD events
L.J. Pan, PhD thesis