Description |
Due to the intimate connection between R-parity and
B-L symmetry, the question of whether sneutrino vevs do or do not
obtain, and keep, an expectation value plays a key role in
differentiating Supersymmetric unified models and their
cosmology. We showed that sneutrino vevs must vanish in
renormalizable models that incorporate the Seesaw mechanism. Then
R-parity is preserved to low energies so that the LSP is stable and
thus an ideal dark matter candidate. Such LR Supersymmetric Seesaw
models unify within 126-plet Higgs containing (and thus `unstrung')
Susy SO(10) GUTs that fit all known fermion data without invoking
non-renormalizable operators. Fermion fits in terms of GUT
parameters lead to distinctive predictions regarding sfermion
spectra such as the prediction of a large A0 parameter and normal
s-hierarchy. On the other hand, sneutrino type odd B-L vevs are
generic to the plethora of `stringy' SO(10) models that utilize
16-plet Higgs vevs and singlets and violate R-parity maximally. Such
models utilize `composite 126-plets' and non-renormalizable
operators to fit the fermion phenomenology. Recently an early epoch
of sneutrino vevs has been identified as enabling primordial
Supersymmetric inflection based on the NLH flat direction of the MSSM.
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