G. Dvali et M. Shifman, Surviving on the slope: Supersymmetric vacuum in the theories where it is not supposed to be, PHYS LETT B, 454(3-4), 1999, pp. 277-280
In supersymmetric models with the run-away vacua or with the stable but non
-supersymmetric ground state there exist stable field configurations which
restore one half of supersymmetry and are characterized by constant positiv
e energy density. We call these solutions "vacua" since they are stable wit
h respect to local deformations of the fields. The energy-momentum tensor f
or these configurations is proportional to diag{1,-1,-1,0), i.e. they break
(spontaneously) the Lorentz and rotational invariances. The formal foundat
ion for such vacua is provided by the central extension of the N = 1 supera
lgebra with the infinite central charge. (C) 1999 Published by Elsevier Sci
ence B.V. All rights reserved.