Grand Unification with non-abelian-gauge horizontal symmetry inspired by the 4d fermionic superstring
- Institute for High Energy Physics, Protvino (Russian Federation)
- Moscow State Univ. (Russian Federation)
- Institute for High Energy Physics, Padua (Italy)
In the framework of the four-dimensional heterotic superstring with free fermions the authors investigate the rank eight Grand Unified Superstring Theories (GUST) that contain the SU(3){sub H} gauge family symmetry. GUST of this type accomodate naturally three fermion families presently observed and, moreover, can describe the fermion mass spectrum without high dimensional representations of conventional unification groups. The authors explicitly construct GUST with gauge symmetry G = SU(5)xU(1)x(SU(3)xU(1)){sub H}{contained_in}SO(16) in the free complex fermion formulation. As the GUST originating from Kac-Moody algebras (KMA) contain only low dimensional representations, it is usually difficult to break the gauge symmetry. The authors solve this problem, taking for the observable gauge symmetry the diagonal subgroup G{sup sym} of the rank 16 group GxG {contained_in}SO(16)xSO(16){contained_in}E(8)xE(8). Such a construction effectively corresponds to a level two KMA, and therefore some higher dimensional representations of the diagonal subgroup appear. This (due to GxG tensor Higgs fields) allows the authors to break GUST symmetry down to the SU(3{sup c}) x U(1){sub em}. In this approach, the observed electromagnetic charge Q{sub em} can be viewed as a sum of two Q{sup I} and Q{sup II} charges of each G group. In this case, below the scale where G x G breaks down to G{sup symm}, the spectrum does not contain particles with exotic fractional charges. In these GUST, there has to exist {open_quotes}superweak{close_quotes} light chiral matter. 17 refs., 2 figs., 8 tabs.
- OSTI ID:
- 107549
- Journal Information:
- Physics of Atomic Nuclei, Vol. 58, Issue 5; Other Information: PBD: May 1995; TN: Translated from Yadernaya Fizika; 58: No. 5, 947-960(1995)
- Country of Publication:
- United States
- Language:
- English
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