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The Property of Ds(2700)

The Property of Ds(2700). Guo-Li Wang Department of Physics, Harbin Institute of Technology, China. Outline. Experimental aspects of Theorical studies Summary. Experimental aspects. In the year 2006, Belle Collaboration reported a new charmed state through the decay

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The Property of Ds(2700)

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  1. The Property of Ds(2700) Guo-Li Wang Department of Physics, Harbin Institute of Technology, China

  2. Outline • Experimental aspects of • Theorical studies • Summary

  3. Experimental aspects • In the year 2006, Belle Collaboration reported a new charmed state through the decay PRL. 100 (2008) 092001

  4. Earlier, BARBAR observed a structure PRL. 97 (2006) 222001

  5. Recently, BARBAR’s new observation arXiv:0908.0806

  6. BARBAR also detected the ratios: and the average ratio:

  7. Theorical studies • Around 2700 MeV, the vector charmed state can be the excited state of • It can be a) the first radial excited state b) the orbitally excited state c) or the mixing state • I do not cover the possibilitis of it being a molecule and a four quark state, or others.

  8. Theorical prediction of mass • For the mixture states

  9. If the square relations for the masses of the mixing states are used: so we have

  10. All of upper states have the OZI allowed strong decay channels: for examples: F.E.Close, C.E.Thomas, O. Lakhina, E. Swanson, PLB 647 (2007) 159 B. Zhang, X. Liu, W. Deng, S. Zhu, Eur.Phys. J. C50 (2007) 617 P. Colangelo, F. Fazio, S. Nicotri, M. Rizzi, PRD 77 (2008) 014012 D. Li, B. Ma, arXiv: 0911.2906 X. Zhong, Q. Zhao, arXiv: 0911.1856 ………

  11. Theorical predictions of decays

  12. So it seems the S-D mixture state of Ds(2700) isfavored. • This conclusion is also obtained by many authers, Zhang’07, Zhong’09, Li’09, etc al

  13. Production of Ds(2700) • Belle have the data (PRL. 100 (2008) 092001) • Which can help us to determine the property of Ds(2700)

  14. Our theoretical prediction of its production • The transition amplitude of can be written as where we have used the naïve factorization, and

  15. This theoretical results are very sensitive to the values of decay constants, we have used: • Our theoretical predictions:

  16. Finally, we obtained

  17. So, it seems that the new state of Ds(2700) should be 2S-1D mixture state • And a 2Sdominate state, mixed with a little 1D component.

  18. Another assignment of Ds(2700) 1, Since low state is 2S dominant, because of the note structure, it is difficult for a 2S dominant state to has a broad width like 100 MeV

  19. 2, The massesof 2S and 1D are very close, and the masses of mixed low state and high state are even closer, for example, we got only 43 MeV of the mass gap, which is much smaller than themiddle value of full width of Ds(2700) from experiment. so two of the mixed states should be exist in the region where experiment detect the new state Ds(2700) with a broad full width.

  20. 3,Two states assignment can easily fit the data of full width and decay ratios. So thenew state can be two mixed overlapping states

  21. Summary • Ds(2700) can be a mixture 2S-1D state, and it is 2S dominant state, mixed with a little component from 1D. • Ds(2700) can be two overlapping states, these two states have so close masses, and same decay channels and broad widths, they can not be separated by current experiment.

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