Equivalence of Different Descriptions for η Particle in Simplest Little Higgs Model

In the SU(3) simplest little Higgs model, a characteristic particle is the light pseudoscalar boson η, it can leads to interesting signals in the LHC/ILC and has been studied in the literature with different parameterizations. We
show that these different descriptions for η particle are equivalent up to some SU(3) rotations as long as we suitably redefine the pseudo-Goldstone boson fields. We evaluate the necessary SU(3) rotations and build up explicit expressions for redefined fields.