Chiral07, Nov. 13, 2007

 Vector and Axial-vector structures of the Q+

Hyun-Chul Kim

NuRI & Department of Physics, Pusan National University

Busan, KoreaCollaborators: T. Ledwig, M.V. Polyakov, K. Goeke

Chiral07, Nov. 13, 2007

MotivationCLAS Results

Very recent CLAS experiments to search for : Null results!Cross sections of : 0.8 nb in 90% CL

Cross sections of : 3nb in 90% CL

K* Exchange is of great importance in describing the above reactions!

Another recent DIANA experiment to search for

, V.V. Barmin et al. [DIANA Collaboration] arXiv :hep-ex / 0603017

New results on will be reported from the LEPS soon.

KNQ coupling must be very small!

Chiral07, Nov. 13, 2007

Transition Form factors

coupling constant for NQK* coupling constant for NQK

Chiral07, Nov. 13, 2007

Hedgehog Ansatz:

SU(3) χQSM

5( ) ~i i i

A Ai i

i occ

i MU

x

+

5( ) exp( ( ) )A AiU x xf

Selfconsistent Soliton:

Chiral07, Nov. 13, 2007

SU(3) χQSM

Chiral07, Nov. 13, 2007

Collective Quantization

: Imbedding into SU(3)

Chiral07, Nov. 13, 2007

Form factors in the cQSM

Example:

Chiral07, Nov. 13, 2007

Results

Chiral07, Nov. 13, 2007

Results

Mixing parameter for the octet & antidecuplet

Chiral07, Nov. 13, 2007

Vector meson dominanceVector meson dominance: Current Field Identity (CFI)

Riazuddin-Fayyazuddin relation

Chiral07, Nov. 13, 2007

Results

Oh et al.:

Nam, Hosaka, HChK::

The present predictions turn out to be much smaller than the above references!The tensor coupling is finite and is of the same order of the vector coupling!

No tensor couplings!

Chiral07, Nov. 13, 2007

Results

Leading contributions are almost cancelled by the rotational corrections!

Chiral07, Nov. 13, 2007

Results

For the nucleonA. Silva, HChK, D.Urbano, K. GoekePhys. Rev. D 72 (2005) 094011

Chiral07, Nov. 13, 2007

Results

• We investigated the vector and axial-vector tran-sition form factors for N Q transitions, based on the chiral quark-soliton model.

• For the electric transition, the wave-function cor-rection turns out to be of leading order (generalized Ademollo-Gatto theorem).

• The K* and K coupling constants are obtained to be very small.

• The width of the Q is shown to be less than 1 MeV.

• We anticipate the new result of the LEPS collabo-ration (T. Nakano).

Chiral07, Nov. 13, 2007

Summary and Conclusion

Chiral07, Nov. 13, 2007

Thank you very much!