Speaker
Description
In $N=1$ supergravity (SUGRA) supersymmetric (SUSY) and non-supersymmetric
Minkowski vacua originating in the hidden sector can be degenerate. This allows for
consistent implementation of the multiple point principle (MPP) assumption.
We present no--scale inspired SUGRA model where the MPP assumption is realised
at the tree--level without extra fine-tuning. In the supersymmetric phase in flat Minkowski space SUSY may be broken dynamically inducing tiny vacuum energy density which can be assigned, by virtue of MPP, to all other phases including the one in which we live.We argue that the measured value of the cosmological constant, as well as the small
values of quartic Higgs self--coupling and the corresponding beta function at the Planck
scale, which can be obtained by extrapolating the Standard Model (SM) couplings to
high energies, can originate from supergravity (SUGRA) models with degenerate vacua.
This scenario is realised if there are at least three exactly degenerate vacua. In the first vacuum, associated with the physical one, local supersymmetry (SUSY) is broken near the Planck scale while the breakdown of the $SU(2)_W\times U(1)_Y$ symmetry takes
place at the electroweak (EW) scale. In the second vacuum local SUSY breaking
is induced by gaugino condensation at a scale which is just slightly lower than
$\Lambda_{QCD}$ in the physical vacuum. Finally, in the third vacuum local SUSY
and EW symmetry are broken near the Planck scale.
