1. 梁伟红
(广西师范大学)
2015强子物理与核物理前沿研讨会，中国科学院大学，2015年1月10-11日

2. Introduction and motivation
CONTENTS
Introduction and motivation
Formalism
Results and discussions
Summary

3. Introduction and motivation
The nature of the light scalar mesons is a topic of long-standing debate.
In the Quark Model: meson
Comparing with the Quark Model’s predictions, there exist
much more light scalar mesons.
Scalar mesons below 1 GeV:
Possible structures:

4. Chiral Unitary Theory:
[Oller and Oset, NPA620(1997)438]

5. [Oller and Oset, NPA620(1997)438]

6. testing the nature of the light scalar mesons
is a good place for
testing the nature of the light scalar mesons
Experimental results:
LHCb: PLB698(2011)115; PRD86(2012)052006; PRD87(2013)052001;
PRD89(2014)092006; PRD90(2014)012003;
Belle, PRL106(2011)121802; CDF, PRD84(2011)052012;
D0, PRD85(2012)

7. In this work:
Considering the final state interactions between the meson pairs
in chiral unitary theory,
can be produced dynamically.

8. Formalism
are the matrix elements of the Cabbibo-Kobayashi-Maskawa (CKM) matrix, related to the Cabbibo angle:
The pair is allowed to hadronize into a pair of pseudoscalar mesons.

10. (direct mechanism)
(rescattering mechanism)
(rescattering mechanism)

12. 3-momentum cut off renormalization scheme
divergent
3-momentum cut off renormalization scheme
following the Bethe-Salpeter Equation in coupled channels:
Diagrammatical representation of BS equation.

13. The V matrix elements are taken from
V is the potential which is obtained from the lowest order chiral Lagrangian for PS-PS interaction,
——the pion decay constant
There are 5 coupled channels:
The V matrix elements are taken from
[Oller and Oset, NPA620(1997)438]
[Gamermann, Oset, PRD76(2007)074016]

16. Results and discussions
[LHCb, 2014]
Clean case:

18. Exp.
Conclusion:
Our results agree with the experimental results. This gives a strong support to the idea of the low lying scalar mesons as being formed from the interaction of pairs of pseudoscalar mesons.
Exp.

19. Summary

20. Thank you for your attention!