We investigate the integrable structures in an N=2 superconfomal Sp(N)
Yang-Mills theory with matter, which is dual to an open+closed string system.
We restrict ourselves to the BMN operators that correspond to free string
states. In the closed string sector, an integrable structure is inherited from
its parent theory, N=4 SYM. For the open string sector, the planar one-loop
mixing matrix for gauge invariant holomorphic operators is identified with the
Hamiltonian of an integrable SU(3) open spin chain. Using the K-matrix
formalism we identify the integrable open-chain boundary conditions that
correspond to string boundary conditions. The solutions to the algebraic Bethe
ansatz equations (ABAE) with a few impurities are shown to recover the
anomalous dimensions that exactly match the spectrum of free open string in the
plane-wave background. We also discuss the properties of the solutions of ABAE
beyond the BMN regime.Comment: 18 pages, one eps figure, v3: typos corrected, clarifying footnotes
added, treatment of complex roots revise