1. Results on Charmonium and Bottomonium
Tom Browder (University of Hawaii)
Will cover results from BESII, CLEO(-c), BaBar and Belle
Apologies: Not an expert but a backup speaker. Can only cover a small subset of interesting results in the available time.
Thanks: I have borrowed from talks by Pedlar, Shepard, Olsen, Muramatsu, Mussa, CZ Yuan, Skwarnicki. I have benefitted from correspondence with Soren Prell and others.

2. Charmonium mesons formed from c- and c-quarks What is V(r) ?? c c r
S. Olsen
mesons formed from c- and c-quarks r c c
c-quarks are heavy: mc ~ 1.5 GeV  2mp
velocities small: v/c~1/4 (for b b, v/c ~0.1)
non-relativistic QM applies _
What is V(r) ??

3. “Cornell” potential c c r slope~1GeV/fm “confining” large distance
component
V(r)
1/r “coulombic”
short distance
component
G.S.Bali
hep-ph/
2 parameters:
slope & intercept

4. Charmonium spectrum

5. D-meson + anti-D meson mass threshold
1-- Charmonium states
Important BES contribution to R
Directly accessible via e+e- annihilation e+
J/y y y’ e-
s(e+e-hadrons)
Y(4160)
Y(4040) y”
Y(4415)
D-meson + anti-D meson mass threshold
“narrow”
(G~300KeV)
“narrow”
(G~100KeV)
“wide”
(G~25 MeV)
y”  DD decay
channel is open
G(DD)25MeV

6. (3770), (4040), (4160), (4415)
In 1998 and 1999, BES scanned 91 energy points
between 2 and 5 GeV to determine R.
Phys. Rev. Lett. 84, 594 (2000) and 88, , (2002).

7. Results from the new R analysis (2007)
hep-ex:

8. Resonance parameters (PLB660, 315 (2008))

9. Current J/ and (2S) Samples (×106)
Note: B( ψ(2S)->+-J/ψ)~32% one can tag J/ψ events very cleanly and efficiently.
BESII : J/ 2001 – 58 M; CLEO-c: (2S) M
CLEO-c has CsI(Tl) crystals, BESII does not but BESIII will .

10. Inclusive photon signal for ψ’γ ηc
B(ψ(2S)->γ ηc (1S)) = ( )*10^-3 B(J/ ψ->γ ηc (1S)) = ( )%
B(J/ ψ->γ ηc (1S))/B( ψ(2S)->γ ηc (1S)) =
Renormalize ηc BF scale
arXiv:

11. Signal for J/ψγηc
Discrepancy between ηc properties (especially widths) in different processes is unresolved.

12. Calculable from”1st principles” Good agreement with measurements
P-wave states
Gamma energy spectrum
from y’g X decays
accessible via E1 transitions from y’
Gaiser et al (Crystal Ball) PRD
E1 Transition Partial width
23S1 (y’)13P2 (cc2) keV
Calculable from”1st principles”
Good agreement with measurements
23S1 (y’)13P1 (cc1) keV
23S1 (y’)13P0 (cc0) keV
13P2 (cc2) 13S1(J/y) keV
13P1 (cc1) 13S1(J/y) keV
13P0 (cc0) 13S1(J/y) keV

13. “reasonable” agreement between
Hadronic transitions
G(y’p+p-J/y) 70 keV
“allowed”
“reasonable” agreement between
measurement & theory
c.f. Kuang & Yan PRD
G(y”p+p-J/y) 50 keV
“allowed”
G(y’hJ/y)  5 keV
allowed
G(y’p0J/y)  0.3 keV
isospin violating p0 h
p+p-
p+p-

14. The hcand ηc(2S) have been observed
CLEO update
The hcand ηc(2S) have been observed
ψ0 hc0γ ηc
Belle 2002
Charmonium table below D Dbar threshold is complete

15. Recent results on non-exotic charmonia
21S0 (ηc(2S)) found by Belle
S.K.Choi et al PRL
properties as expected
23P2 found by Belle
hep-ex/
properties as expected
11P1 (hc) found by CLEO
hep-ex/
properties as expected
13D1  g 13P1 g 11P0
seen by CLEO,
Phys.Rev.D74:031106,2006.
G(meas) = 75  18 keV
G(theor)  ~59-77 keV

16. The potential model for (ccbar) charmonium mesons is robust and reliable.
The old “missing states” (hc and ηc(2S)) have now been observed
Declare victory
May 1, 2003

17. Old unsolved mystery Problems with strong decays of charmonium K*K ρπ
MARK-II
Old unsolved mystery
K*K
X-H Mo et al, review in hep-ph/ (>10 proposals)
W. S Hou’s idea, glueball-J/ψ mixing, seems to be ruled out ρπ
Rosner
One possible explanation

18. ’  Baryon Anti-baryon OK
First measurements by BESI, remeasure BR with BESII data sample.
ΞΞ-bar
’  Ξ- Ξ+  p2π-p2π+
’  Σ0 Σ0  pπ-pπ+
ΣΣ-bar
’  ΛΛ  pπ-pπ+
ΛΛ-bar
’  pp
pp-bar
Consistent with “12% rule”.

19. Bottomonium Data Samples
BaBar, 30.3 fb-1, ~120 M Y(3S)
Belle 2.9 fb-1 (2006) , 11 M Y(3S)
~14.4fb-1 on the Y(2S)

20. Bottomonium: Some mysteries in strong decays
“QCD Multipole Expansion”
What is special about the case m-n > 1 ?

21. Most famous ancient mystery (1994-2000)

22. Possible Theoretical Explanations:
High statistics data and sophisticated analysis may provide some clues (CLEO)

23. The matrix element for Υ(mS)Υ(nS)
The amplitudes A, B could be complex
In the above, ε, ε’ are the polarization vectors of the Υ(nS), Υ(mS)
q1, q2 are the pion 4-vectors while E1, E2 are their energies in the Υ rest frames. q2 is the invariant mass of the two pions

24. CLEO High Statistics Analysis of di-pion matrix element
M, θX

25. CLEO High Statistics Analysis of di-pion matrix element
A, B are complex. B was previously neglected
C is consistent with zero (spin flip and breakdown of QCD multipole expansion not present).
PRD 76, (2006)

26. Recent data for Υ(4S)Υ(1S,2S) + -
Non-B Bbar decay
Belle data
BaBar data
PRL 96 (2006)
PRD (R) 2007

27. CLEO’s first evidence for (2S)(1S) η
preliminary
4.6σ
One candidate is found,
Expect this is 16% of the η mode

28. BaBar discovers Υ(4S)(1S)η
These are examples of non-B Bbar decays that have been observed by BaBar and Belle.
preliminary

29. Could related transitions provide a way to discover the elusive hb or ηb ?
Two suggestions:
(Voloshin, Mod. Phys. Lett. A 19, 2895 (2004))
(Godfrey, Rosner, PRD66, (2002) like CLEO’s hc search )

30. Where is the ground state bottomonium ηb ?
Tests theory and is the highest priority of the quarkonium working group (QWG)
Direct M1 transitions
Which Upsilon(nS) is best ? Inclusive or exclusive ? What are the hadronic modes of the ηb ?

31. Second mystery or big problem in the field:
Where is the ηb, the ground state bottomonium state ?

33. Search for a Y(4260) analogue in the bottomonium sector
Y(4260) → J/y p+ p-
Is there a corresponding bb state Ub → U(1S) p+ p- ?
“Searching for the bottom counterparts of X(3872) and Y(4260) via + -Υ(1S)”,
Wei-Shu Hou, PR D74, (2006) → theory inspiration
(experimental work by Kai-Feng Chen and Anatoly Sokolov)
Resonant structure is rather complicated above BB threshold.
E.g. Y(10860) is commonly assumed to be a radially excited 1-- b b bound state a.k.a the Y(5S), but we do not really know that.
World wide Y(10860) data:
1985 CLEO /fb
2003 CLEO III /fb
2005 Belle /fb
2006 Belle /fb
Total cross-section
Collected mainly for Bs physics, ≈105 Bs / fb
Use this data to measure + - Υ(1,2,3S) production at the (10860)

34. Anomalous U(1,2,3S) p+p-, U(1S) K+K- cross sections at U(5S)
PRL 100, , 21.7 fb-1
Final state
U(3S)
U(2S)
20s
U(1S)
Initial state
Gtot MeV
GU(1S)p+p- keV
U(2S)
0.032 6
U(3S)
0.020
0.9
U(4S)
20.5
1.8
U(10860)
110
590
U(10860)
4.9s
U(3S)
U(2S)
U(1S)
U(10860) decay or decay of new overlapping state Yb? Energy scan (7.9 / fb) around U(10860) : compare U(1S) p+p- and total hadronic cross sections. Results will be ready soon.
U(10860)
U(1S)

35. What about the dipion mass distributions for the Y(10860)
What about the dipion mass distributions for the Y(10860) ? (the state formerly known as the “Υ(5S)”)
Phase space, Cahn-Brown model (B=0)
There are hints of a low mass structure in a) and b) but statistics are low.

36. Bottomonium: New Physics Potential
Suppose those precision electroweak fits are taken literally, MH~76±30 GeV.
Suppose nMSSM is correct, then there is a H and another light Higgs particle a1 (m(a1) <m(b)). Can avoid LEP limits and still have MH~100 GeV. (R. Dermisek, J. Gunion, B. McElrath)
The dominant decay mode might be:
Difficult at a hadron collider. But could find the light Higgs (a1) in bottomonium at B or Super B Factories.

37. Bottomonium: New Physics Potential (cont’d)
One motivation for BaBar’s 30 fb-1 Y(3S) run.

38. Hunting dark matter or light Higgs in Υ(nS) decays
High precision check of lepton universality in dilepton decays
Light Higgs signature
Can also search for the HYPER-CP particle using decays to aμ+ μ-

39. BaBar’s final run
Kirkby
Expect compelling results on bottomonium from BaBar (and perhaps Belle) in the near future.

40. More New Results (but not enough time to cover)

41. New Measurements of Upsilon(3S) Branching Fractions (CLEO)

42. New Measurements of Upsilon(3S) Branching Fractions (CLEO)

43. If there are bb versions of the XYZ’s, why not ss versions as well?
It looks like there may be a bb version of the Y(4260) lurking around the (5S)
W.-S. Hou PRD 74, (2007)
If there are bb versions of the XYZ’s,
why not ss versions as well?

44. 1-- Ys states around 2 GeV? @ Ecm ~10.6 GeV Y(2175)f0(980)f
from BaBar
(confirmed by BESII)
e+e-  g f0(980)h
@ Ecm ~10.6 GeV
confirmed by BESII
M(f0(980)f GeV
M.Ablikim et al (BES)
PRL 100, (2008)

45. Backup Slides

46. The new 2007 improved results
Comparison of the updated R value and the old results in Phys. Rev. Lett. 88 (2002)
preliminary
Differences in R values are due to the updated resonant parameters and initial state radiative correction factor (1+obs).
hep-ex:

47. ’  Baryon antibaryon OK
BESII – CLEOc
comparison
pp-bar
ΛΛ-bar
ΣΣ-bar
ΞΞ-bar
Consistent with SU(3) symmetry.
Reduced Branching Ratios
R = Br/(π p* /s½), p* is baryon
momentum.
R’s same under SU(3) symmetry.
BES
Phys. Lett. B648, 149 (2007)

48. Belle: G((5S)pp(nS))
is Huge!!
(4S)pp(1S)
477 fb-1 from Belle
(1/20 times the data &
~1/10th the crosssection)
8 times as many events! 2S 3S 4S
(4S)  (1S) p+p-
“(5S)”pp(1S)
23.6 fb-1 from Belle
325±20 evts!
44±8 evts
Belle
K.F. Chen et al (Belle)
PRL 100, (2008)
(2 weeks ago)

49. PDG value taken for (nS) properties
Partial Widths
Assume “(5S)” = (5S)
PDG value taken for (nS) properties
N.B. Resonance cross section ± nb at GeV
PRD 98, (2007) [Belle]
>100 times bigger!! Cf
(2S)  (1S) p+p- ~ 6 keV
(3S) keV
(4S) keV

51. Where is the ground state bottomonium ηb ?
Tests theory and is the highest priority of the quarkonium working group (QWG)
Which Upsilon(nS) is best ? Inclusive or exclusive ? What are the hadronic modes of the ηb ?