1. New hadrons spectroscopy @ BaBar
Maurizio Lo Vetere
University of Genova & INFN
Representing the Collaboration
Particles and Nuclei International Conference
October 24-28, 2005 (PANIC05)

2. Outline of the talk Charmonium spectroscopy Ds spectroscopy
X(3870)
Y(4260)
Ds spectroscopy
D*sJ(2317)
DsJ(2460)
DsJ(2632)
Charmed barions
c+
c0 @

3. Charmonium spectrum
States below open charm threshold well known and in agreement with potential models
Most states above open charm threshold are missing. Those known have quantum numbers JPC=1- - because are produced through virtual  in e+e- annihilation
Other kind of states are possible (DD* molecules, diquark-antidiquark, hybrids)
DD* y’ DD
hc’ hc
ccJ y hc
New states discovered at B factories. Among others: X(3872), Y(4260).

4. The X(3872) observation
Discovered by Belle(1) in B KX, XJ/y p+p- (compatible with J/y r0)
BELLE
PRL 92, (2003)
CDF
PRL 93, (2004)
BABAR
PRD 71, (2005) D0
PRL 93, (2004)
MX= ± 0.5 MeV/c2 slightly above D0D*0 threshold
GX<2.3 MeV/c2 at 90%CL; JPC=1++ favoured(2)
(1) PRL 91, ; (2) hep-ex/

5. Possible interpretations
What is the X(3872)?
B(cc)K is a typical B decay mode
Isospin violating decay into J/yr0 would be against charmonium hypothesis
No state predicted at this mass
Exactly at DD* threshold
Possible interpretations
Charmonium (1)(2)
D0-D0* molecule (3)(4)
Diquark-antidiquark state (5)
others…
Need experimental result to test models:
Quantum numbers, decay modes, possible charged partners
(1) Barnes et all. , PRD 69, (2004)
(2) Eichten et all., PRD 69, (2004)
(3) Swanson, PLB 588, 189 (2004)
(5) Maiani et all., PRD 71, (2005)
(4) Tornqvist, PLB 590, 209 (2004)

6. BX(3872)K, X(3872)J/y p+p- 211 fb-1
hep-ex/
B±X(3872)K±
If X(3872) is a charmonium state models predict similar production rates in B0 and B+ decays;
If X(3872) is a DD* molecule, models(1) predict suppression in B0 decays;
If X(3872) is a tetra-quark: states produced in B0 e B+ decays differ and it is expected Dm ~ (7 ± 2) MeV/c2 (2)
Babar preliminary
6.1s
B0X(3872)Ks
(1) Braaten and Kusunoki, PRD 71, (2005);
(2) Maiani et all , PRD 71, (2005).
Babar preliminary
2.5s
More data needed to discriminate between models

7. Search for X(3872) charged partners
212 fb-1
B0X-(J/yp-p0)K+
B-X-(J/yp-p0)Ks
PRD 71, (2005)
Isospin multiplet predicted by molecolar models:
BR(B X-K) ~ 2 BR(B X0K)
No charged partner observed
Isovectors C.L.10-4
Search for BX(3872)K, XJ/
82 fb-1
PRL 93,
m(J/yh) GeV/c2 y’
3.872
Some models(1) predict large branching ratios
No signal observed
(1) PLB 574, 210

8. Inclusive charmonia in B decay
210 fb-1
B±XCCK± K± X
Recoil B
Y(4S)
Reconstructed B
Novel variation on the recoil technique Measurement of the K± momentum spectrum in B center-of-mass frame
No signal is observed for B+X(3872)K+:
BR(B+ X(3872)K+) < 3.210-4 
BR(X(3872) J/+–) >4.2%, 90% C.L.
No signal is observed for charged partners
in B0X(3872)+K-:
BR(B0X (3872)+K-)<5·10-4 at 90% C.L.
Babar
preliminary
Recoil Mass
High mass states:
cc1, y’, y’’ and hc’ seen

9. The Y(4260) observation 233 fb-1 e+e-  gISR J/y(l+l-) p+p-
hep-ex/
e+e-  gISR J/y(l+l-) p+p-
Babar
preliminary
 may go undetected
No X(3872) evidence.
No (4040), (4160), (4415).
Observed (>8) a broad structure Y(4260):
N = ± 23
M = 4259 ± MeV/c2
 = ± MeV/c2
(Ye+e-) · BR(YJ/yp+p-)=5.5± eV/c2
JPC=1--
Impossible to distinguish between 1 or more resonances.

10. Search for Y(4260) in B decay
211 fb-1
hep-ex/
B±Y(4260)K±;Y(4260)J/y p+p-
Excess of event observed at 4260 MeV
M, G fixed to the ISR analysis values
N = 128 ± 42 events
Significance: 3.1s
BR(B-YK-)·BR(YJ/yp+p) = (2.0±0.7±0.2)×10-5
Babar
preliminary
R measurements compatibility
4.260 GeV
(e+e- Y(4260)  J/ +-)
~4%
(e+e- hadrons)
BR(Y J/ +-) must be high despite
state above D(*)D(*) threshold

11. Charmonium summary X(3872) (1)
Observed in neutral and charged B decay:
BX(3872)K, X(3872)->J/+-
BR( X(3872)->J/+- 90% C.L.
No isovector charged partners observed
No X(3872)->J/ decay observed
Not seen in ISR events
Y(4260) consistent with assignment JP=1--:
recently observed by Babar in ISR events
evidence for B± -> Y(4260)K± decay
statistic doesn’t allow to distinguish between one or more
state hypotheses
Further investigations are needed to understand the nature of these states.
(1) BELLE favuor JP=1+ assignement.

12. New charmed mesons Quantum numbers needed
Four states known before B-factories data Ds(1968)+, Ds*(2112)+, Ds1(2536)+, Ds2*(2573)+ in good agreement with theoretical predictions.
Two new states discovered by BABAR(1) and CLEO(2): DsJ*(2317)+ (into Ds+0 ), DsJ(2460)+ (into Ds*+0).
Missing 0+,1+ states?
Masses significantly lower than predictions.
Isospin violation decay.
SELEX(3) claims a state at M= 2632 MeV decaying into Ds+ and D0K+.
Quantum numbers needed
Other possible interpretations?
tetraquark(4) or molecules(5).
(1) PRL 90, ; (2) PRD 68, ; (3) PRL 93,
(4) PRD 71, ; (5) PRD 68,

13. DsJ*(2317)Ds0 and DsJ(2460)Ds*0
123 fb-1
hep-ex/
High Ds* sideband
DsJ(2460)
DsJ*(2317)
DsJ*(2317)ɣ
Ds*ɣɣ
Ds*ɣ
DsJ(2460)Ds*(Dsɣ)0
DsJ(2460)
Low Ds* sideband
m(DsJ*(2317))=2318.90.3(stat.)
0.9(syst.) MeV/c2 (below D(*)K threshold)
m(DsJ(2460))=2459.11.3(stat.)
1.2(syst.) MeV/c2(below D*K threshold)

14. More Dsj(*) decay modes
123 fb-1
hep-ex/
Search for radiative and dipion transitions in order to confirm or rule out some of these hypotheses
Ds+ɣ (JP=1,2,…)
Ds++- (JP=0-,1,2…)
DsJ(2460)
Reflections:
DsJ*(2317)Ds0(ɣɣ)
DsJ(2460)Ds0 (ɣɣ)ɣ
Ds1(2536)
DsJ(2460)
DsJ*(2317)
DsJ(2460)Dsɣ excludes JP=O±
Absence consistent with JP=0+; allowed for all other natural parity

15. Search for B  D(*) DsJ(*)+
113 fb-1
hep-ex/
Side bands m(DsJ(*))
fit results
Compatible with predictions from:
Bardeen et all., Phys.Rev. D68, (2003)
qh helicity angle for DsJ(2460)  Ds. Solid line expectation for J=1, dotted line expectation for J=2.
J=1 good agreement
J=2 excluded

16. Search for DsJ(*) isovector partners
123 fb-1
hep-ex/
DsJ*(2317)0
DsJ*(2317)++
Some authors* have discussed the possibility of a four quark content in DsJ states in order to explain the low mass of these states
T. Barnes, F.E.Close and H.J.Lipkin, Phys. Rev., D68, (2003)
H. J. Lipkin, Phys. Lett. B580, 50(2004)
T.E. Browder, S. Pakvasa, and A. A. Petrov, Phys. Lett. B578, 365(2004)
BaBar sees no evidence for DsJ(2317)0Ds+ - or DsJ(2317)++Ds+ +

17. Search for DsJ(2632) Ds ,D0K+,D*Ks
125 fb-1
Ds+(1020)+, K*(892)0K+
ɣɣ where
ɣ 0ɣɣ
ɣ Ds*+Ds+ɣ
hep-ex/
BaBar sees no evidence for DsJ (2632)  Ds, D0K+, D*+Ks

18. DsJ mesons summary DsJ* (2317)+ consistent with assignment JP=0+:
observed in Ds*0 system
not seen in Ds* or Ds* +  -
DsJ* (2460)+ consistent with assignment JP=1+:
observed in Ds*0 , Ds+ , Ds*+ -
helicity in B  D DsJ(2460)+ decays consistent
No evidence for isovector DsJ* (2317)+ partners
No evidence for DsJ* (2460)+ state
Evidence so far points out that DsJ may be interpreted as two ordinary cs mesons; yet the low mass of the DsJ states has still to be understood.

19. C+ mass measurement Systematic uncertainties scale with Q-value:
Best measurement from CLEO (1)
(1) P. Avery et al., Phys. Rev. D43, 3599
BABAR: large sample of charmed hadrons
high momentum and vertex resolution
well known alignment
precise knowledge of field and material distribution
Systematic uncertainties scale with Q-value:
a  b + c + … Q = m(a) - m(b) - m(c) - …
JP = ½ +
We choose to recostruct C+ in its lower Q-value final states:
c+ 0 KsK+ ( 0 p- , Ks+-) Q-value: 178 MeV/c2
c+ 0KsK+ ( 0  0  ) Q-value: 101 MeV/c2
Systematic uncertainties considerably smaller than higher statistic modes:
c+pK- Q-value: 713 MeV/c2
c+pKs Q-value: 850 MeV/c2

20. c+ 0KsK+, 0KsK+ 232 fb-1 hep-ex/0507009 c+ 0KsK+ c+ 0KsK+
4627 events
267 events
Higher statistic and Q-value mode:
systematic errors dominate
Lower statistic and lower Q-value mode:
statistical errors dominate

21. Systematic uncertainties
Materials effect
Main syst. uncertainty due to energy loss
corrections due to detector materials
Ks0,  fitted mass values indicate
under-estimated amount of material
Fitted masse values studied as a function
of radial decay distance
Largest deviations at low decay radii
Increased SVT density by 20% in track reconstruction algorithms
Magnetic field effect
Solenoidal field well measured
Effects due to PEP II permanent magnet material magnetized by solenoid field
Increased magnetization of PEP II magnets by 20%
Systematic effects evaluated and assigned proper error
m( c+ 0 KsK+ ) = ± (stat) ± (syst) MeV/c2
m( c+ 0 KsK+ ) = ± 0.181(stat) ± (syst) MeV/c2
combined measurement: m( c+) = ± 0.14

22. c decays and life times
Still missing

23. c -+, -+-+, -K-++
225 fb-1
hep-ex/
S=17.8
S=2.4
c -+
S=3.4
c -K-++

24. Production of c0 in B decays

25. Conclusions
Still missing

26. Backups

27. BaBar detector 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% 1m

28. Experimental technique