photoproduction of q and its vector and axial-vector structure

NSTAR 2009, Beijing, China

Hyun-Chul Kim (Hyun-Chul Kim ( 金鉉哲金鉉哲 ))

Department of Physics, Inha University

Collaborators: T. Ledwig, K. Goeke, Seung-il Nam


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

K*N & KN couplings must be very small!K*N & KN couplings must be very small!

• Miwa et al, Phys. Rev. C 77, 045203: No clear peak!

Diff. Cross sections for : 3.5 b/Sr in 90% CL

K*N coupling must be very small!

KEK Results

• Did the CLAS results put a period to the existence of the pentaquark?

• Wohl in 2008 Review of Particle Physics:“The whole story – discoveries themselves, the tidal waves of papers by theorists and phenomenologists that followed, and the eventual “undiscovery” – is a curious episode in the history of science.”

• In the meanwhile……



• Another recent DIANA experiment to search for

,

KN couplings must be also tiny!

DIANA Results

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

SVD Results

A.Aleev et al. [SVD Collaboration] arXiv :0803.3313


K*N couplings must be very small!

Future experiments at J-PARC to search for

LEPS New Results

T. Nakano et al. [LEPS Collaboration] Phys. Rev. C 79, 025210

• If the exists or not……• If it exists, its width must be below 1 MeV

and its existence must be reaction-dependent!• At any rate, K*N and KNcouplings must be

very small!• In the present talk, we aim at investigating these

two coupling constants, based on which we study photoproduction of the .

• We will also estimate the cross sections of the photoproduction of the .



coupling constant for NK*

coupling constant for NK

NSTAR 2009, Beijing, China HChK et al. Prog. Part. Nucl. Phys. Vol.37, 91 (1996)

sealevels:

energyincreases

valencelevel:

energydecreases

system stabilzes



Hedgehog Ansatz:

5( ) ~

i i i

A Ai i

i occ

i MU

x

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

f

Selfconsistent Soliton:No Free parameter to play with!All parameters have been fixed before.

HChK et al. Prog. Part. Nucl. Phys. Vol.37, 91 (1996)


SU(2) Witten imbedding into SU(3): SU(2)XU(1)



We treat the angular frequency and strange quark mass perturbatively.


NSTAR 2009, Beijing, China T.Ledwig, HChK, K. Goeke, Nucl.Phys. A 811, 353-377 (2008).


Mixing parameter for the octet & antidecuplet

T.Ledwig, HChK, K. Goeke, Nucl.Phys. A 811, 353-377 (2008).


Riazuddin-Fayyazuddin relation



Oh et al.:

Nam, Hosaka, HChK::

The present predictions turn out to be much smaller than the above references!

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!The tensor coupling is finite and is of the same order of the vector coupling!



comparable to those from the Nijmegen potential.

For test, we have derived octet baryon coupling constants within the same formalism, for example,

The coupling constants for the Theta are an order-of-magnitude smaller!


Leading contributions are almost cancelled by the rotational corrections!


For the nucleon

A. Silva, HChK, D.Urbano, K. Goeke

Phys. Rev. D 72 (2005) 094011

Axial-vector constantsare well reproduced!

NSTAR 2009, Beijing, China T.Ledwig, HChK, K. Goeke, Phys.Rev. D 78, 054005 (2008).

(Experimental data)

(Present result)

Delta decay is quite underestimated!

(No meson-loop corrections!)


D.Diakonov, V. Petrov, M. Polyakov,Zeit. Phys. A 359, 305 (1997)

Model-dependent ratiotaken from Blotz et alwithout symmetry conserving quantization

Present result

Had Diakonov et al. used the present result, they woud get the decay width:

without changing

instead of 15 MeV (30 MeV).

NSTAR 2009, Beijing, China T.Ledwig, HChK, K. Goeke, Phys.Rev. D 78, 054005 (2008).

DIANA Collaboration

< 1 MeV !


Total cross sections

S.i. Nam and HChK, Phys. Rev. D 79, 034031 (2009)


Total cross sections with and without K*



Differential cross sections with and without K*


Enhancement in the forward direction!


Differential cross sections with and without K*



Beam asymmetries with and without K*


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

• For the electric transition, the wave-function correction 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 is shown to be less than 1 MeV. • We also estimated the total cross sections,

differential cross sections, and beam asymmetries for the photoproduction with the present results.



Thank you very much!


Backup materials Collective operators for the baryon-baryon-meson coupling constants

Leading order:

Rotational corrections:

photoproduction of q and its vector and axial-vector structure

Documents

nqk nstar

nq knq couplings

vector coupling

tensor coupling

coupling constants

chinaknq couplings

diana collaboration

svd collaboration arxiv