1. Quarkonium spectroscopy and new states from BaBar
Lorenzo Vitale
Università and INFN
Trieste, ITALY
on behalf of BaBar Coll.
DIS06, Apr 20-25, 2006
Lorenzo Vitale

2. PEPII & BaBar: not only B physics
SVT:
97% efficiency – 20mm z resol
SVT+DCH:
s(pt)/pt=0.13%·pt+0.45%
EMC:
s(E)/E=2.32%·E-1/4+1.85%
Asymmetric energy B-Factory & Detector
were optimized for CP in B physics …
Excellent tracking and vertexing
Excellent particle identification
Excellent γ, π0 detection
Data:
~330 fb-1 recorded so far
GeV ϒ(4S)
~360 M BB pairs
GeV qq
… but plenty of other topics
can be investigated
THIS TALK: QUARKONIUM 1m
DIS06, Apr 20-25, 2006
Lorenzo Vitale

3. T.Barnes, S.Godfrey and E.S.Swanson
Heavy Quarkonia Spectra
Rich spectroscopy. Predictions become more critical when states are above the threshold for open flavour production
Bottomonium Charmonium
Y(4260)? S/P?
ϒ(4S)
X(3872)?
T.Barnes, S.Godfrey and E.S.Swanson
Phys.Rev. D (2005)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

4. Selected quarkonium topics in this talk:
Bottomonium results:
hadronic non-BB decays of ϒ(4S)
Charmonium results:
Results on new particles in B decays and ISR events:
X(3872)
Y(4260)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

5. Bottomonium Studies: hadronic non-BB decays of ϒ(4S)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

6. Hadronic non-BB decays of ϒ(4S)
ϒ(4S)BB mostly, but not only. BF of O(10-4) are expected.
Cleo reported only upper limits of that order.
LP-05: Belle reports first evidence for ϒ(4S) +- ϒ(1S)
B=(1.0±0.2±0.4)•10-4 with 386•106 (4S)
hep-ex/ , still preliminary
We have predictions for partial widths and dipion spectrum in
ϒ(mS) +- ϒ(nS), mS nS
QCD multipole expansion (Kuan-Yan, PRD24(1981),2874 and many others)
But model fails to describe dipion spectrum at low mass in 3S  1S
No clear explanation yet
(Mixing and coupled channel effects are not accounted for in those models)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

7. BaBar: ϒ(4S) +- ϒ(nS)
BaBar Analysis strategy search for ϒ(4S) +- ϒ(nS)
with ϒ(nS)  l+l-
Results on l+l-=+-,
use e+e- as cross check
(Bhabha bkg)
211fb-1
preliminary
DATA 211fb-1 on peak:
(230.0±2.5)•106 (4S) decays
22fb-1 ~40MeV below (4S)
as a control sample
(no (4S) candidates found)
Validations with ISR returns to
2S1S & 3SnS
The transition 4S->3S is kinematically not allowed
The diagonal band is a QED process like a radiative Bhabha or +- gamma followed by photon conversion
or ISR 4pi events.
DIS06, Apr 20-25, 2006
Lorenzo Vitale

8. PRELIMINARY Results preliminary preliminary preliminary
ϒ(4S)+-ϒ(1S)
10 signal significance BF=(0.90±0.15)·10-4
=1.8±0.4 keV
ϒ(4S)+-ϒ(2S)
First
BF=(1.29±0.32)·10-4
=2.7±0.8 keV
preliminary
Dipion spectra compared with QCD multipole expansion:
4S1S compatible
4S2S incompatible (peak at low M+-)
preliminary
Significance n-sigma here is in terms of “Gaussian equivalent” number of sigma's n=sqrt(2logdeltaLik)
Diagonal band: bhabha bkg
Drop in eff. in first bin due to e+e- cut
To be submitted to PRL
DIS06, Apr 20-25, 2006
Lorenzo Vitale

9. Results on X(3872) History & Theory NEWS from BaBar: 2 recently published results 1 preliminary result
DIS06, Apr 20-25, 2006
Lorenzo Vitale

10. Brief history: 2003 discovery (cc interpretation?)
First observed by Belle in B± → K±(J/ +-)
Mass just at D0D0* threshold
Narrow (<2.3 MeV at 90%CL)
Compatible with J/0
→IC=1+ final state
Then confirmed by
CDF, D0 and BaBar
all in the same decay mode.
Belle PRL 91 (2003)
CDF PRL 93 (2004)
D0 PRL 93 (2004)
BaBar PRD 71 (2005)
Width consistent with experimental resolution
Remember that final state J/0 has I=1
1 Since ro_0 doesn’t decay in pi_0 pi_0 so it would be interesting to look for pi_0 pi_0 J/psi
2 large total width expected in potential models
Ordinary charmonium interpretation in trouble.
This width eliminates many possible assignments.
This mass value and absence of c1 are in disagreement with potential model expectations for the 13D2 (JPC=2--) charmonium state
DIS06, Apr 20-25, 2006
Lorenzo Vitale

11. Several Possible Interpretations of X(3872): cc, D0D
Several Possible Interpretations of X(3872): cc, D0D*0 molecule, diquark-antidiquark, …?
Ordinary cc charmonium state
T. Barnes and S. Godfrey, PRD 69 (2004)
E.J. Eichten, K. Lane and C. Quigg, PRD 69 (2004) (aka Cornell potential model)
S-wave D0D*0 molecule
N.A. Tornqvist, PLB 590 (2004) 209
M.B. Voloshin, PLB 579, 316
C.Y. Wong, PRC 69 (2004)
E. Braaten and M. Kusunoki, PRD 69 (2004) , 71(2005)
E.S. Swanson, PLB 588 (2004) 189
Dominant 1++ (2P) cc component +
D0D*0/D0D*0 continuum component
C. Meng, Y.J. Gao and K.T. Chao, hep-ph/
M. Suzuki, PRD 72 (2005) (mainly charmonium + channel coupling to DD*)
S-wave diquark-antidiquark bound state cucu
L. Maiani, F. Piccinini, A.D. Polosa and V. Riquer, PRD 71(2005)014028
Hybrid ccg
B.A. Li, PLB 605 (2005) 306
Vector glueball gg + a small mixture of cc
K.K. Seth, hep-ph/
S-wave threshold enhancement in D0D*0 scattering
D.V. Bugg, PRD 71 (2005) 
DIS06, Apr 20-25, 2006
Lorenzo Vitale

12. Several experimental studies: other decay modes, production mechanism, “partners”, …
BaBar PRL 93 (2004)
no signal for X(3872)  J/ 
BaBar PRD 71 (2005)
no signals for isovector charged partners of X(3872)
 rate should be twice, isovector hypothesis ruled 10–4 level
 IX=0 large isospin violation in J/ +- decay
BaBar PRD 71 (2005)
no evidence in ISR production  JPC=1-- excluded
Cleo PRL 94 (2005)
no evidence in  fusion and rad. production  JPC0-+, 0++, 2++
Belle Preliminary Moriond QCD 06 (also LP05)
~5 evidence of B K D0D*0 (2++ is not favored)
Belle hep-ex/ hep-ex/
~4 evidence of X(3872)J/ and X(3872)J/ sub- threshold  both suggest C=+1
 JPC=1++ favored from angular analysis (against 0++, 0-+)
isovector hypothesis ruled 10–4 level in terms of ratio of probability to observe the expected signal
divided null hypothesis, while BF(B0->K+X-)<5.4 10–6
DIS06, Apr 20-25, 2006
Lorenzo Vitale

13. X(3872) J/ +- with increased statistics
in B0 and B+ decays at BaBar
B±→X(3872)K± B0→X(3872)Ks
PRD 73 (2006)
61.2± σ ± σ
211 fb-1
M=3871.3±0.6±0.1 MeV/c2 M=3868.6±1.2±0.2 MeV/c2
R = BF(B0→X(3872)Ks)=0.50±0.30± ΔM=2.7±1.3±0.2 MeV/c2
BF(B±→X(3872)K±)
The sign of ΔM is not clear in these predictions
R & ΔM can be compared with model predictions
R: some molecule model predicts R~0.1 (excluded?)
ΔM: ~7±2 MeV/c2 in qqqq model Statistics still low
DIS06, Apr 20-25, 2006
Lorenzo Vitale

14. Search for radiative decays of X(3872)
Preliminary
X(3872)→J/ 
in B± → K±X
signal extraction validated
looking at B+c1K+
260 fb-1
Implies C=+1
Preliminary results:
19.2 ± 5.7 events
BF(B+X(3872) K+)(X(3872)J/ ) = (3.4±1.0±0.3) x 10-6
R = BF(X(3872) J/ ) = 0.34±0.14
BF(X(3872) J/+-)
C=+1 cf E.S. Swanson, PLB 598 (2004) 197
Confirms 4σ Belle signal
with consistent BF & R
hep-ex/ (2005)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

15. Inclusive Search for B±K±X(3872)
PRL 96 (2006)
Novel technique variant of recoil technique:
 one B is fully reconstructed
charged K momentum distribution in the recoil rest frame system shows peaks due to two body decays
• Observation of X states independent of the decay mode
 Allows absolute BF measurement
• Huge bkg due to K in recoil B decays e.g. B→ K  J/
No signal:
BF(B→XK)<
3.2
BF(XJ/ +-)>
211fb-1
The lower limit set on BF(XJ/ +-) is sensitive to the distribution of charm quark inside the X(3872)
so it can help in understanding the nature of this state
Observed signals are consistent with exclusive measurements
DIS06, Apr 20-25, 2006
Lorenzo Vitale

16. Y(4260) DIS06, Apr 20-25, 2006 Lorenzo Vitale
Another charmonium related state has been observed by BaBar
DIS06, Apr 20-25, 2006
Lorenzo Vitale

17. BaBar Observation of Y(4260) in ISR
Discovered last year in ISR events JPC=1--:
e+e-ISR+-J/
J/+-, e+e-
PRL 95 (2005)
(2S)
233 fb-1
Y(4260)
12523 events
8  Significance
Confirmed by CLEO in energy scan (also in 00J/ mode)
hep-ex/
In this analysis the photon may go undetected and
actually is reconstructed (24+-8)% in agreement with 25% for the psi(2S)
Peak xsec (51 pm 12) pb
this number is written only in ISR ppbar paper (PRD 73 (2005)
though is from this analysis (here the paper says only around 50 pb)
from J/ sideband
DIS06, Apr 20-25, 2006
Lorenzo Vitale

18. Y(4260):Hadronic/dimuon cross section
Y(4260) is not observed in the total e+e-hadrons cross section (a dip!), indicating that (Ye+e-) is much smaller than corresponding partial width of all known JPC=1-- charmonium resonances, while (Y+-J/) is much larger.
Y(4260) R
From this we infer that (e+e-Y)<3x0.6 nb  (Ye+e-)<200 eV and (Y+-J/)>2 MeV
Factors >10 and >20 larger than J/+- partial width of (2S) and (3770), resp.
√s (GeV)
Also here there are several interpretations alternative to conventional charmonium. It is important to search for the Y(4260) in other decay modes ….
DIS06, Apr 20-25, 2006
Lorenzo Vitale

19. No Indication for Y(4260) in Other ISR-produced Final States
BABAR: 232 fb-1
PRD 73, (2006)
BABAR: 232 fb-1
To be subm.to PRD
BABAR: 289 fb-1
To be subm.to PRL
preliminary
M(K+K-)
Y(4260)
Shaded:  sidebands
preliminary
Shaded: D
sidebands
(3770)
DD(3900)
(4040)
(4160)
(4415)
Remember to say that in this way BF(pi+pi-phi)/BF(pipiJ/psi)<0.1at 90%CL that would exclude glueball hypothesis
that predicts these to be equal.
Remember to say that BF(pipiJ/psi) is large despite this state is above D*D* threshold
DIS06, Apr 20-25, 2006
Lorenzo Vitale

20. Indication of Y(4260) in B decays
PRD 73, (2006)
211 fb-1
3.1σ significance, assuming mass and width from ISR analysis;
needs confirmation
BF(B±Y(4260) K±, Y(4260) +-J/= (2.0±0.7±0.2) 10-5
DIS06, Apr 20-25, 2006
Lorenzo Vitale

21. Summary New/First measurements of non-BB hadronic decays of the ϒ(4S)
 +- ϒ(nS)
Partial widths compatible with expectations
Dipion spectrum in 4S2S incompatible with QCD multipole expansion
Found several states above the threshold for open flavour production
showing unusual properties for an ordinary charmonium state:
X(3872) I=0, JPC=1++
narrow state, produced in B decays and observed in several decay modes
Y(4260) I=0, JPC=1--
broad state, produced in ISR events (and some indication in B decays), no DD decays seen
FURTHER INVESTIGATION IS NEEDED TO UNDERSTAND THE NATURE OF THESE STATES
DIS06, Apr 20-25, 2006
Lorenzo Vitale

22. Backup slides
DIS06, Apr 20-25, 2006
Lorenzo Vitale

23. Known Heavy Quarkonia Spectra
Rich spectroscopy with predictions that became more critical when states are close to the threshold for open bottom or charm production
DIS06, Apr 20-25, 2006
Lorenzo Vitale

24. Charmonium production @ B-factories
ISR production can give useful complementary information (even no signal)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

25. Mass of X(3872) Mavg = 3871.90.6 MeV/c2 , <2.3 MeV/c2 (90% CL)
D0D*0=3871.31.0 MeV/c2 D+D*+=  1.0 MeV/c2
DIS06, Apr 20-25, 2006
Lorenzo Vitale

26. no signals for charged partners of X(3872)
no signal for X(3872)  J/ 
no evidence in  fusion and radiative production at
CLEO
234M BB
PRD 71 (2005)
90M BB
PRL 93 (2004)
PRL 94 (2005)
DIS06, Apr 20-25, 2006
Lorenzo Vitale

27. Evidence for sub-threshold decay X(3872)J/
Evidence of X(3872)J/
Evidence for sub-threshold decay X(3872)J/
hep-ex/
275M BB
X(3872)
275M BB
M(+-0) (GeV/c2)
MJ/ (GeV/c2)
10.63.6 events
4.3 
13.6 4.4 events
stat. sig.: 4.0 
hep-ex/
The evidence of the two decay modes suggests the C parity of X(3872) be +1
DIS06, Apr 20-25, 2006
Lorenzo Vitale

28. Properties of the X(3872): search for D0D00 decay mode
Select B(D0D00)K events
An excess M(D0D00) ~ MX is seen
N=12.5±3.9
(>5)
Rule out 2++
(strong D-wave suppression)
Preliminary
Br(XDD)/Br(X→ p+p-J/y) =12±5
DIS06, Apr 20-25, 2006
Lorenzo Vitale

29. BaBar Observation of Y(4260) in ISR
ISR events with K+K-J/ spectrum show a featureless mass spectrum  exclude the possibility of K and  misidentification.
ISR events with a nJ/ with additional pions show no structure that could feed down to produce Y(4260) in +-J/ mass spectrum.
Y(4260) not from two-photon events
no substantial improvement obtained by including (4040), (4160) or (4415) in the fits
A single relativistic BW (multiplied by PS factor and
convoluted with Cauchy resolution function)
+ 2nd order polynomial are used in the fit.
if the observed signal is due to two interfering resonances
1st resonance: M  4260 MeV/c2,   50 MeV
2nd resonance: M  4330 MeV/c2,  narrow
Signify the presence of 1-- state containing hidden charm.
DIS06, Apr 20-25, 2006
Lorenzo Vitale