1. Theoretical review of excited D*/Ds* mesons
Xiang Liu
Lanzhou University
The 4th International Workshop on Charm Physics, Oct.21-24, 2010, IHEP, Beijing

2. Outline Excited charmed-strange meson Excited charmed meson
Experiment + phenomenology
Summary
Xiang Lanzhou U.

3. Charmed-strange state
Xiang Lanzhou U.

4. DsJ(2317) Four-quark state?
The low mass puzzle of DsJ (2317) and DsJ (2460)
DsJ(2317)
Phys.Rev.Lett.90:242001,2003
Experimental masses are 100 MeV lower than the expected values in quark models
S. Godfrey and R. Kokoski, PRD 43, 1679 (1991); S. Godfrey and N. Isgur, PRD 32, 189 (1985); M. Di Pierro and E. Eichten, PRD 64, (2001)
Barnes, Close, Lipkin PRD68, (2003)
Cheng, Hou, PLB566, 193 (2003)
Chen, Li, PRL93, (2004)
Four-quark state?
Coupled-channel effect plays an important role to understand the low mass puzzle
van Beveren, Rupp, PRL91, (2003) RSE
EPJC32, 493 (2004)
Dai, Li, Zhu, Zuo, EPJC55, 249 (2008) QSR
Liu，Liu，Zhu PRD79, (2009) CHPT
Phys.Rev.D68:032002,2003
DsJ(2460) C
Charmed-strange
meson
Godfrey, PLB568, 254 (2003)
Colangelo, De Fazio, PLB570, 180 (2003).
Dai, Huang, Liu, Zhu, PRD68, (2003)
Xiang Lanzhou U.

5. Xiang Liu @ Lanzhou U. Phys.Rev.Lett.97:222001,2006
Phys.Rev.D80:092003,2009
Ds1(2710)
DsJ(2860)
DsJ(3040)
hep-ex/
Belle
Xiang Lanzhou U.

6. Obtained ratio of D*K/DK is consistent with experimental data.
BaBar measurement
Phys.Rev.D80:092003,2009
Xiang Lanzhou U.

7. Charmed-strange meson
Exotic state
Quantum number
Mixing
2 S D
2 S
1 D
Mutiquark state   3 1
More efforts are needed to distinguish different explanations to Ds1(2710)
Xiang Lanzhou U.

8. D*K/DK=0.36, which is smaller than experimental value
It can be fully excluded since DsJ(2860)->D*K channel was observed at BaBar
Phys.Rev.D80:092003,2009
BaBar data
D*K/DK=0.36, which is smaller than experimental value
Xiang Lanzhou U.

9. Ratio of D*K/DK consistent with experimental data
Babar data
Phys.Rev.D80:092003,2009
Ratio of D*K/DK consistent with experimental data
Xiang Lanzhou U.

10. 2S state DsJ(2710): 1 1D state DsJ(2860)
Sun, Xiang Liu, PRD80,
2S state
DsJ(2710): 1 -
1D state
DsJ(2860)
Matsuki, Morii, Sudoh, EPJA31, 701 (2007)
Chen, Wang, Zhang, PRD80, (2009) A semi-classic flux tube model
Zhong, Zhao, PRD81, (2009) Constituent quark model with effective Lagrangian
Colangelo, Fazio, arXiv:  [hep-ph] Effective Lagrangian approach
Xiang Lanzhou U.

11. Charmed state
Xiang Lanzhou U.

12. The observations of D(2550), D(2610), D(2750) and D(2760)
arXiv:
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13. 1 3 Resonance parameters See Benitez’s talk to find more details - - -- 1 - 3 - or
arXiv:
2P or 1D state
Xiang Lanzhou U.

14. The possible assignments to D(2550), D(2610) and D(2760)
D(2550) is 0 charmed meson since D(2550) is only observed in the invariant
mass spectrum of D*π
D(2610) can be assigned as a pure 2S state
Supported by the analysis of angular distribution and mass spectrum
If D(2750)=D(2760), the spin-parity
content of D(2760) can be either 1
or 3 because the observed decay
D(2760)DK fully excludes 2
a pure 1D state or mixing state -
D(2610) can also be as the partner of D(2760)
Xiang Lanzhou U.

15. Study strong decay behaviors of D(2550), D(2610) and D(2760)
How to distinguish and test the possible assignments to D(2550), D(2610) and D(2760)?
arXiv:
Study strong decay behaviors of D(2550), D(2610) and D(2760)
by Quark Pair Creation model
Xiang Lanzhou U.

16. Sun, Yu, Xiang Liu, Matsuki We expect further experiment to test it
D(2550)
The calculated total strong decay width of D(2550) as 2S state is far less than the BaBar data.
Is the quark model calculation not appropriate in this case?
Chiral Quark Model  D(2550) narrow state
X.H. Zhong, arXiv:
Is 2S assignment not suitable to explain D(2550)?
J =0 assignment is supported by the analysis of angular distribution and mass spectrum!
Is D(2550) the overlap of several charmed mesons?
P -
Sun, Yu, Xiang Liu, Matsuki
arXiv: -
We expect further experiment to test it
Xiang Lanzhou U.

17. Sun, Yu, Xiang Liu, Matsuki, arXiv:1008.3120
D(2610)
Vector charmed meson with mixing of 2S and 1D states 
Overlap between theoretical and experimental values
A pure 2S charmed meson 
Ф=0 radians total decay width is far less than BaBar data
Xiang Lanzhou U.

18. Sun, Yu, Xiang Liu, Matsuki, arXiv:1008.3120
D(2760)
Two times smaller than BaBar data
Mixing of 2S and 1D  as partner of D(2610) with J = 
A pure 1D charmed meson J = 
Ф=0 radians total decay width is far larger than BaBar data
The 1D charmed meson with J =  P
Xiang Lanzhou U.

19. Summary Charmed-strange mesons
DsJ(2860):
DsJ(3040): the first radial excitation of Ds1(2460) P state (1+3)
search for the remaining three 2P states in future experiment
Charmed mesons
Three newly observed charmed states D(2550), D(2610) and D(2760)
 2S and 1D states
Abundant excited D/Ds mesons were observed in the past 7 years!
Good opportunity and full of the challenges Effort from theory and
experiment
Candidates for 2S and 1D states
Search for the remaining 2S and 1D states
Xiang Lanzhou U.

20. Thank you for your attention!
Xiang Lanzhou U.