1. Understanding DsJ*(2317) and DsJ(2460)
OUTLINE
Spectroscopy of mesons containing a single heavy quark
New evidences of positive parity charmed states
Evaluation of their strong and radiative widths
Predictions in the beauty sector
Rossella Ferrandes
Bari University
Frascati, 17 May 2005

2. chromomagnetic interaction
Description of hadrons containing a single heavy quark Q
QCD lagrangian for the heavy quark:
chromomagnetic interaction
kinetic energy
spin flavour symmetric
subleading in the limit

3. Q q Qq mesons are classified in doublets labeled by SlP: Sl = Sq + L
In the infinite heavy quark mass limit, the heavy quark spin SQ and the light degrees of freedom angular momentum Sl decouple Q q
Qq mesons are classified in doublets labeled by SlP:
J = Sl + SQ
Sl = Sq + L
States differing for the heavy quark spin orientation are degenerate in mass.

4. Strong decays M (MeV) D2* D1 D1 D0* D* D slP=1/2- slP=1/2+ slP=3/2+
2600
D2* D1
2400
s-wave decays
(broad) D1
D0*
2200 D*
2000 D
1800
d-wave decays
(narrow)
slP=1/2-
slP=1/2+
slP=3/2+

5. Belle cu cd Broad states previously established slP=3/2+ axial vector
newly found slP=1/2+ scalar
previously established slP=3/2+ tensor
newly found slP=1/2+ axial vector
previously established slP=3/2+ axial vector
Broad states

6. cs
BaBar
CLEO
DsJ*(2317)
DsJ(2460)
Belle
narrow states

7. helicity analyses favour J=1
Spin-parity assignment for DsJ*(2317)
observation of
decay
natural spin-parity: 0+, 1-, 2+...
decay
not observed
BaBar
0+ assignment favoured
decay
not observed
Spin-parity assignment for DsJ(2460)
observation of
decay
spin-parity: 0-, 1+, 2-...
Belle
observation of
decay
J=0 assignment ruled out
observation of
decay
JP= 1+ favoured
helicity analyses favour J=1

8. Different interpretations:
For slP= 1/2+ strange states potential models typically predict masses larger than the experimental values, above the DK and D*K thresholds
2504 MeV
So slP= 1/2+ states were expected to have large widths
2364 MeV
In the interpretation as cs states, the experimental resonances are narrow because of isospin violation.
Different interpretations:
4-quark state (H. Y. Cheng et al. 03)
molecule (Barnes, Close, Lipkin 03)
atom (Szczepaniak 03) …
BaBar
Looking for isospin partners:
CDF

9. To identify the experimental resonances with cq states of SlP=1/2+ doublet we must
calculate strong widths
calculate radiative widths
obtaining
for non strange states:
large widths
for strange states:
width < experimental resolution
according to experimental values

10. Effective lagrangian describing interactions between heavy mesons and
pseudoscalar light mesons
based on
heavy quark spin-flavour symmetry
chiral symmetry for light mesons Q qa

11. Analogously for the axial state:
Strong decays
Non strange states h
(QCD sum rules)
P. Colangelo et al., PRD (95)
Considering also
decay
Experimentally:
Analogously for the axial state:

12. Gasser and Leutwyler, NPB (1985)
Strange states
Isospin violating decays
mixing
Gasser and Leutwyler, NPB (1985)
Analogously for the scalar state:

13. Casalbuoni et al., Phys. Rept. (1997)
Radiative decays
suppressed as 1/mc
VMD (Vector Meson Dominance)
Casalbuoni et al., Phys. Rept. (1997)

14. Overall agreement with experiments supports our interpretation
Summary of the results:
P. Colangelo, F. De Fazio, PLB (03)
P. Colangelo, F. De Fazio, RF, MPL A (04)
meson
experimental width (MeV)
evaluated width (MeV)
Overall agreement with experiments supports our interpretation
0.1
predictions
0.5
0.2
0.4
the role of 1/mc corrections currently under investigation

15. chromomagnetic interaction centre of mass of the doublet
Predictions for beauty mesons belonging to 1/2+ doublet
M=P, V
M=S, A
kinetic energy
chromomagnetic interaction
centre of mass of the doublet

16. Analogously for non strange states:1
meson
mass (MeV/c2)
width (MeV/c2)

17. Experimental measurements consistent with canonical interpretation
CONCLUSIONS
Charm sector
Strange states:
widths << experimental resolution
Experimental measurements consistent with canonical interpretation
consistent with experimental values
Non strange states:
widths consistent with experimental
measurements (~100 MeV)
Beauty sector
Predictions of masses and widths for beauty mesons belonging to 1/2+ doublet

18. Backup transparencies

19. Analogous situation for and doublets
cq mesons
bq mesons
Mesons belonging to
doublet
Analogous situation for and doublets

20. experimental masses
large states
narrow states