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Cosmological Restrictions on Conformally Invariant SU(5) GUT Models

Giampiero Esposito·Gennaro Miele·Luigi Rosa
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Abstract

Dirac's theory of constrained Hamiltonian systems is applied to the minimal conformally invariant SU(5) grand-unified model studied at 1-loop level in a de Sitter universe. For this model, which represents a simple and interesting example of GUT theory and at the same time is a step towards theories with larger gauge group like SO(10), second-class constraints in the Euclidean-time regime exist. In particular, they enable one to prove that, to be consistent with the experimentally established electroweak standard model and with inflationary cosmology, the residual gauge-symmetry group of the early universe, during the whole de Sitter era, is bound to be SU(3) x SU(2) x U(1). Moreover, the numerical solution of the field equations subject to second-class constraints is obtained. This confirms the existence of a sufficiently long de Sitter phase of the early universe, in agreement with the initial assumptions.

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Giampiero Esposito, Gennaro Miele, Luigi Rosa. 1995-07-02. Cosmological Restrictions on Conformally Invariant SU(5) GUT Models. https://doi.org/10.1088/0264-9381%2F10%2F7%2F007

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