  We use perturbative series expansions about a staggered dimerized ground
state to compute the ground state energy, triplet excitation spectra and
spectral weight for a one-dimensional model in which each site has an $S=\case
1/2$ spin ${\bf S}_i$ and a pseudospin ${\bf T}_i$, representing a doubly
degenerate orbital. An explicit dimerization is introduced to allow study of
the confinement of spinon excitations. The elementary triplet represents a
bound state of two spinons, and is stable over much of the Brillouine zone. A
special line is found in the gapped spin-liquid phase, on which the triplet
excitation is dispersionless. The formation of triplet bound states is also
investigated.
