Is Theta+(1540) a Kaon--Skyrmion Resonance?
Abstract
We reconsider the relationship between the bound state and the SU(3) rigid rotator approaches to strangeness in the Skyrme model. For non-exotic S=-1 baryons the bound state approach matches for small m_K onto the rigid rotator approach, and the bound state mode turns into the rotator zero-mode. However, for small m_K, we find no S=+1 kaon bound states or resonances in the spectrum, confirming previous work. This suggests that, at least for large N and small m_K, the exotic state may be an artifact of the rigid rotator approach to the Skyrme model. An S=+1 near-threshold state comes into existence only for sufficiently large SU(3) breaking. If such a state exists, then it has the expected quantum numbers of Theta+: I=0, J=1/2 and positive parity. Other exotic states with (I=1, J^P=3/2+), (I=1,J^P=1/2+), (I=2, J^P=5/2+) and (I=2,J^P=3/2+) appear as its SU(2) rotator excitations. As a test of our methods, we also identify a D-wave S=-1 near-threshold resonance that, upon SU(2) collective coordinate quantization, reproduces the mass splittings of the observed states Lambda(1520), Sigma(1670) and Sigma(1775) with good accuracy.
Cite
@article{arxiv.hep-ph/0309305,
title = {Is Theta+(1540) a Kaon--Skyrmion Resonance?},
author = {Nissan Itzhaki and Igor R. Klebanov and Peter Ouyang and Leonardo Rastelli},
journal= {arXiv preprint arXiv:hep-ph/0309305},
year = {2010}
}
Comments
22 pages. More details on SU(2)_I excitations of Theta+, version published on NPB