1. X(3872), Y(3915) & Charged Zc states
Stephen Lars Olsen
Seoul National University
New Hadron Spectroscopies/Dynamics WS
Haeundae, Busan Nov. 19, 2012

2. charmonium (cc) meson spectra_
Charmonium
All of the states below 2mD
have been assigned
Many radiative transitions have
been measured with widths
that agree with theory
A number of hadronic transitions
(y’ppJ/y; hJ/y; p0J/y; p0hc)
have been measured, also with
widths that agree with theory
Above 2mD a number of states
have been found that have defied
assignment to a charmonium level
& most have anomalously large
hadronic transition widths
e.g.; G(y’hJ/y) ≈ 10keV; G(y3ShJ/y) ≈ 1MeV
G(y’p+p-J/y)≈100keV; G(Y4260)p+p-J/y) > 1MeV

3. bottomonium x102 p+p- agree with theory (MeV) p+p- p+p- p+p- p+p-

4. The X(3872)

5. Latest result on the X(3872)
CMS at HCP2012 (Kyoto) last week
X(3872) production very similar to y’ production  X(3827) has a significant cc component _

6. M(p+p-) for X(3872)p+p-J/y
rp+p-
p+p- S-wave
X3872 r p+
J/y p-
E.A. Yetkin, parallel talk Hadron Collider Physics Symposium (Kyoto Nov. 2012)

7. What else we know about the X(3872)
M(X3872) – (mD0 + MD*0 ) = (-120 ± 350) keV
G(X3872) < 1.2 MeV
JPC = 1++ likely, JPC= 2-+ still possible
Bf(BKX3872) x Bf(X3872p+p- J/y) = (8.6 ± 0.8) x 10-6
Bf(X3872p+p- J/y) > 2.6%
Bf(X3872D0D*0)/ Bf(X3872p+p- J/y) =9.3±2.7
Bf(X3872 g J/y) /Bf(X3872p+p- J/y) = 0.21±0.08
Bf(X3872 wJ/y) /Bf(X3872p+p- J/y) = 0.8±0.03
No Isospin partners are found  I=0
this means X3872p+p- J/y violates Ispin symm. _

8. 1++ cc assignment? cc1 ‘ _ ‘ Mass is too low? Theory: Expt: pinned to:
Mcc2=3930 MeV
Mass is too low?
3872 vs 3905 MeV
nr=2 splitting> nr=1 ‘
Theory:
expt upper limit: <2.1
3872 MeV
T.Barnes et al PRD 72,
Expt:
use theory:
c.f.: G(y’p0J/y)≈0.4 keV

9. 2-+ cc assignment? hc2? _ Mass is too high?: Expt:
pinned to:
My”=3770 MeV
&My2=3823 MeV
Mass is too high?:
3872 vs 3837 MeV
Expt:
use theory:
c.f.: G(y’p0J/y)≈0.4 keV
Y. Jiaet al arXiv:
Theor: BKhc2 violates factorization
BKhc not seen
BKcc2 barely seen _
Theory: hc2  DD* expected to be tiny
Belle & BaBar::
G(XDD*)/G(Xp+p-J/y)=9.5±3.1
Y. Kalasnikovaet al arXiv:
hc2ghc(1S) & pphc modes expected to dominate _

10. If not cc, then what? _ D*0 q c c q s c c s D0
Possibilities that have been suggested:
tightly bound
diquark-diantiquark
loosely bound
meson-antimeson
“molecule” _ q c _ c q __
D*0
In color space: _ s
“nuclear” forces c _
p,s _ c
red+blue=magenta
(antigreen)
cyan+yellow=green
(antimagenta) s D0
A colored diquark
is like a antiquark
A colored diantiquark
is like a quark
This likes M(X3872) ≈ mD0+mD*0
& can explain large Ispin violation
This requires existence of isospin (& octet)
partner states, which are not seen.

11. X(3872)-J/y relative sizes
drms(208Pb nucleus)≈5.5 fm + + + +
X(3872)
208Pb + + + +
drms(X3872) ~ 8 fm + + + + + + + +
drms(J/y) ≈ 0.4 fm + + +
J/y
Volume(J/y) /Volume(X3872)
≈ 10-4
How can such a fragile object be produced in H.E. pp collisions? heavy ion collisions??
-- arXiv : sCDF(meas)>3.1±0.7nb vs stheory(molecule)<0.11nb
C. Bignamini et al, PRL 103, :

12. Is the X(3872) the cc1? ‘ _ ‘ M cc potential mass value
Isospin Violation in X(3872) decay: _
3905
DD* screening
MD+ +MD*-
3880 X
≈on mass shell
≈8 MeV off mass shell
MD0 +MD*0
3872
MX(3872) –(MD0 + MD*0) = ± 0.35 MeV _
What pulls M down from 3905 MeV
--past the D+D*- threshold—
exactly to the D0D*0 threshold?
MX(3872) –(MD+ + MD*-)= ± 0.35 MeV _ _
Best guess: X3872 is a cc1 - DD*-molecule
mixture, brought down in mass to mD0+mD*0
by some mechanism I don’t understand. ‘
c.f. B.-Q. Li & K.-T. Chao PRD 79,

13. The Y(3915)
aka X(3915)

14. Y(3915)wJ/y K w w B Y Y J/y J/y Belle gg  wJ/y B+K+ wJ/y Belle
2010
gg  wJ/y
B+K+ wJ/y
Belle
2005
M=3943 ± 17 MeV
G= 87 ± 34 MeV
M=3915 ± 5 MeV
G= 17 ± 11 MeV
M(wJ/y)
M(wJ/y)
gg  wJ/y
BaBar
2008
B+K+ wJ/y
BaBar
2012
M=3919± 3 MeV
G= 13 ± 7 MeV
B0K0 wJ/y
M(wJ/y)
M(wJ/y)
M=3915 ± 5 MeV
G= 34 ± 13 MeV

15. BaBar measurements favor JPC=0++
ql* n
Beam axis
ql*
qln 0+ 2+
BaBar PRD 86, (2012)
arXiv:

16. What we know about the Y(3915)
M(Y3915) = 3917 ± 3 MeV
G(Y3915) = 21 ± 7 MeV
Bf(BKY3915) x Bf(Y3915wJ/y) = (5.1 ± 1.0) x 10-5
G(Y3915gg) x Bf(Y3915wJ/y) = 54 ± 9 eV
Bf(Y3915D0D*0) /Bf(Y3915wJ/y) < 1.3
JPC = 0++ likely
Bf(Y3915DD) /Bf(Y3915wJ/y) < 1.3
G(Y3915wJ/y) ≈1MeV
Published data _ _
My estimates
(see backup slides)

17. Y(3915) = cc0 charmonium state?‘
23P0 cc state _
If Y(3915) = cc0: ‘
-G(cc0wJ/yc0) ≈ 1 MeV
too wide for hadronic
charmonium transitions
c.f.: G(y’p+p-J/y)≈0.1 MeV
- mass is to high:
M(cc2)-M(cc0) ≈ 14 MeV
≈1/10th the n=1 splitting:
M(cc2)-M(cc0)=141 MeV
M=3929 ± 5 MeV ‘ ‘
- Y(3915)DD not seen?
theory predicts:
G(cc0DD) ≈ 30 MeV
my estimate:
G(Y(3915)DD) < 2 MeV _ ‘ _ _

18. Y(3915) & thresholds 3.95 D+D- s s Y(3915) M (GeV) 3.90 D+D*- D0D*0
3.85

19. arXiv:
Gtot= 17MeV
Only VV couplings (no DD coupling):

20. charged Zc charmonium-like states+ u c d c
Smoking guns for 4-quark states

21. BK p+ y’ & BKp+ cc1 M2(p+y’) M2(p+cc1) ??? M2(K+p-) M2(K+p-) ??
K*(890)K+p-
K*(1400)’s
K*(1680)
K*(1430)K+p-?
K3*(1780)
R.Mizuk et al. (Belle) PRD 78,
S.-K.Choi et al. (Belle) PRL100,

22. fit with a 2-body isobar model
Our default model
ky’
K*(890)y’
K*(1410)y’
K0*(1430)y’
K2*(1430)y’
K*(1680)y’
KZ+
K*y’ B
K2*y’
(cc1)
Kpy’
(cc1)
(cc1)
KZ+
(cc1)
Z+ p+ y’
(p+cc1)
(cc1)
with & without

23. BK p+ y’ results with no KZ+ term2 1 1 2 3 4 5
R.Mizuk et al. (Belle) PRD 80, C B A 3 4 A B 5 C
fit CL=0.1% 51

24. BK p+ y’ results with a KZ+ term2 1 B 1 2 3 4 5 A 3 4 C B C A 5
fit CL=36%
R.Mizuk et al. (Belle) PRD 80,

25. BK p+ y’ Dalitz-plot fit results
K* veto applied
With Z(4430)
Significance: s
No big contradiction
BaBar: no confirmation
Without
Z(4430)
B. Aubert et al. (BaBar) PRD 79,
Belle: = ( )x10-5

26. Dalitz analysis of B0K-p+cc1
R.Mizuk et al. (Belle) PRD 78,
DE GeV
M2(p+cc1)
??? G
K3*(1780)
K*(890)
K*(1680)
K*(1400)’s
M (J/yg) GeV

27. Fit model: all low-lying K*’s (no Z+ state)b c d g f e a b e f c d g
C.L.=310-10
R.Mizuk et al. (Belle) PRD 78,

28. Fit model: all K*’s + one Z+ stateb c d g f e a b e f c d g
C.L.=0.1%
R.Mizuk et al. (Belle)
PRD 78,

29. Are there two? ? ? ? ? M2(p+cc1) a b c d M2(p+cc1)
R.Mizuk et al. (Belle) PRD 78,

30. Fit model: all K*’s + two Z+ statesb c d g f e a b e f c d g
C.L.=42%
R.Mizuk et al. (Belle) PRD 78,

31. Two Z-states give best fit
Projection with K* veto
R.Mizuk et al. (Belle) PRD 78, (2008)

32. BaBar doesn’t agree BaBar K* +Z1+Z2 K* only
J. Lees et al. (BaBar) PRD 85, (2012)
BaBar
K* +Z1+Z2
K* only
Conclusion: no >2s evidence for
Z1 or Z2  p+ cc1, set upper limits:

33. Critique of the BaBar critique
constr. interf
BaBar
Belle
incoherent
destructive interf
J. Lees et al. (BaBar) PRD 85, (2012)
R.Mizuk et al. (Belle) PRD 78, (2008)

34. Beautiful examples of charged bottomonium-like mesons in Roman Mizuk’s talk.

35. Summary Lots of new particles found recently
low-lying charmonium/bottomonium states
- cc2, yc2, hb(1P), hb(2P), hb(1S),hb(2S),cb(3P),…
-all match potential model predictions well
X(3872) seems to be the cc1, charmonium state
with a large D0D*0 “molecular” component
why is its mass right at the D0D*0 threshold?
Y(3915)w J/y properties reproduced by a VV
molecule-type model
-JPC=0++, but Y(3915)DD not seen
Clear examples of charged charmonium-like
(& bottomonium-like) states are seen
Z(4430)p+y’; Z1(4050) & Z2(4250)p+cc1
(in spite of what BaBar says!!)
Lots of evidence for molecules as opposed to
diquarks, etc… ‘ _ _ _ _ _

36. Lots of pieces Are they all from the same puzzle? Y(3940) Y(4140)
X(3940)
Are they all from the same puzzle?
X(4160)
Z1(4050)
Y(4660)
Z(4430)
Y(4008)
Z2(4250)
Y(4260)
Y(4360)
X(3872)

37. Does Y(3915)  DD ? _ _ No signal near 3940: BKD0D0 BKy(3770) D0D0
J. Brodzicka et al. (Belle) PRD 100,
BKy(3770)
D0D0
68+15 events |
<16 events
No signal
near 3940:
3915 MeV
Use 16/68 & scale from PDG values: