1. New hadron 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)
Highlights on charmed baryons @

3. Charmonium spectrum The X(3872) observation
States below open charm threshold now well known and in agreement with potential models.
Most states above open charm threshold never seen
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.
The X(3872) observation
Discovered by Belle(1) in B KX, XJ/y p+p-
Confirmed by CDF(2), D0 (3), BABAR (4)
M = ± 0.5 MeV/c2
 < 2.3 MeV/c2
within 1 MeV from D*D threshold
compatible (5) with J/y r0
JPC=1++ favoured (5)
(1) PRL 92, (2003)
(2) PRL 93, (2004)
(3) PRL 93, (2004)
(4) PRD 71, (2005)
(5) BELLE: hep-ex/

4. 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 (cc) 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)

5. 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 and 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

6. 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 molecular models:
BR(B X-K) ~ 2 BR(B X0K)
No charged partner observed
Isovectors C.L.10-4
BABAR
BABAR
Search for BX(3872)K, XJ/
82 fb-1
PRL 93, (2004)
m(J/yh) GeV/c2 y’
3.872
BABAR
Some models(1) predict large branching ratios
No signal observed
(1) PLB 574, 210

7. Inclusive charmonia in B decays
210 fb-1
B±XCCK± K± X
Babar
preliminary
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
cc1, y’, y’’ and hc’ BR compatible with exclusive measurements

8. The Y(4260) observation 233 fb-1 e+e-  gISR J/y(l+l-) p+p-
Phys.Rev.Lett. 95, (2005)
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.

9. 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 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/ +-)
at level R
of 4% (e+e- hadrons)
BR(Y J/ +-) must be large despite
state above D(*)D(*) threshold
GeV

10. 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 do not allow to distinguish between one or more
state hypotheses
Further investigations are needed to understand the nature of these states.
(1) BELLE favour JP=1++ assignment.

11. 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) reported 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,

12. DsJ*(2317)Ds0 and DsJ(2460)Ds*0
123 fb-1
hep-ex/
Ds+0
Ds+0
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)

13. 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 parity

14. Observation of B  D(*) DsJ(*)
Phys.Rev.Lett. 93, (2004)
Side bands m(DsJ(*))
fit results
BABAR
Compatible with predictions from:
Bardeen et all., Phys.Rev. D68, (2003)
DsJ(2460) produced with helicity 0 in B  D DsJ.
qh helicity angle for DsJ(2460)  Ds. Solid line expectation for J=1, dotted line expectation for J=2.
BABAR
J=1 preferred

15. Search for DsJ*(2317) 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
Ds+-
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)
Ds++
BaBar sees no evidence for DsJ(2317)0  Ds+ - or DsJ(2317)++  Ds+ +

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

17. 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 with J=1
No evidence for isovector DsJ*(2317) partners
No evidence for DsJ (2632) 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.

18. New results on charmed baryons
cbaryons (1) :
High precision mass measurement of c making use of the decays c+ 0 KsK+, c+ 0KsK+
(1) hep-ex/
S=17.8
cbaryons (2) :
Studied decay channels: c - +, -+-+, -K-++
Measurement of branching fraction ratios
First observation in a single decay channel with significance >5
First observation of production in B decays
cbaryons (2) :
Studied decay channels: c- K+,  -+
Studies of production from continuum
Studies of production from B decays
(2) hep-ex/
(3) Phys.Rev.Lett. 95, (2005)

19. Backups

20. 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

21. Experimental technique