  Vacuum expectation value of the surface energy-momentum tensor is evaluated
for a massive scalar field with general curvature coupling parameter subject to
Robin boundary conditions on two parallel branes located on (D+1)-dimensional
AdS bulk. The general case of different Robin coefficients on separate branes
is considered. As an regularization procedure the generalized zeta function
technique is used, in combination with contour integral representations. The
surface energies on the branes are presented in the form of the sums of single
brane and second brane-induced parts. For the geometry of a single brane both
regions, on the left (L-region) and on the right (R-region), of the brane are
considered. The surface densities for separate L- and R-regions contain pole
and finite contributions. For an infinitely thin brane taking these regions
together, in odd spatial dimensions the pole parts cancel and the total surface
energy is finite. The parts in the surface densities generated by the presence
of the second brane are finite for all nonzero values of the interbrane
separation. It is shown that for large distances between the branes the induced
surface densities give rise to an exponentially suppressed cosmological
constant on the brane. In the Randall-Sundrum braneworld model, for the
interbrane distances solving the hierarchy problem between the gravitational
and electroweak mass scales, the cosmological constant generated on the visible
brane is of the right order of magnitude with the value suggested by the
cosmological observations.
