  Adopting the q-theory approach to the cosmological constant problem, a simple
field-theoretic model is presented which generates an effective cosmological
constant (remnant vacuum energy density) of the observed order of magnitude,
\Lambda_{eff} \sim (meV)^4, if there exist new TeV-scale ultramassive particles
with electroweak interactions. The model is simple, in the sense that it
involves only a few types of fields and two energy scales, the gravitational
energy scale E_{Planck}\sim 10^{15} TeV and the electroweak (new-physics)
energy scale E_{ew}\sim 1-10 TeV.
