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The Reduction of the Exceptional Groups of String Theory and the Standard Model |
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PP: 1-5 |
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Author(s) |
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Simon Davis,
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Abstract |
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| The phenomenology related to the exceptional groups of string theory will be reviewed. A known success of the E6 model
is an accurate prediction of the Weinberg angle. Spontaneous symmetry breaking produces scalar and fermion fields that do not belong
to the lepton and quark multiplets, and therefore, a description of the standard model is likely to be derived from a group of less
dimension. A comparison with theories that contain compact groups, which are subgroups of the ten-dimensional Lorentz group, is
given. Following reduction of a twelve-dimensional theory, governing the ten-dimensional superstring and heterotic string effective
actions in ten dimensions, over the coset manifold G2×SU(2)×U(1)
SU(3)×U(1)′×U(1)′′
, or the compactified Mklm solution to the eleven-dimensional
supergravity equations, the renormalization group flow of the couplings is found to give the approximate value of sin2qW only for a
certain ratio of hypercharge to nonabelian gauge couplings, which is found to require modification at supersymmetric scales. embedding
parameter k, and then, the ratio of the hypercharge to nonabelian gauge couplings requires modification. The isometry groups of these
coset spaces arise from geometrical considerations, while a unique connection with the larger exceptional group is introduced through
the intersection form of the manifold in four dimensions. |
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