Gauge unification in higher dimensions
A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z{sub 2}'s (Z{sub 2} and Z{sub 2}{prime}), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge symmetry breaking, doublet-triplet splitting, and a vanishing of proton decay from operators of dimension 5. Until 4d supersymmetry is broken, all proton decay from dimension 4 and dimension 5 operators is forced to vanish by an exact U(1){sub R} symmetry. Quarks and leptons and their Yukawa interactions are located at the Z{sub 2} orbifold fixed points, where SU(5) is unbroken. A new mechanism for introducing SU(5) breaking into the quark and lepton masses is introduced, which originates from the SU(5) violation in the zero-mode structure of bulk multiplets. Even though SU(5) is absent at the Z{sub 2}{prime} orbifold fixed point, the brane threshold corrections to gauge coupling unification are argued to be negligibly small, while the logarithmic corrections are small and in a direction which improves the agreement with the experimental measurements of the gauge couplings. Furthermore, the X gauge boson mass is lowered, so that p {yields} e{sup +}{pi}{sup 0} is expected with a rate within about one order of magnitude of the current limit. Supersymmetry breaking occurs on the Z{sub 2}{prime} orbifold fixed point, and is felt directly by the gauge and Higgs sectors, while squarks and sleptons acquire mass via gaugino mediation, solving the supersymmetric flavor problem.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of High EnergyPhysics; National Science Foundation Contract PHY-95-14797; The EuropeanCommission Research Training Networks ContractHPRn-CT-2000-00148
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 860767
- Report Number(s):
- LBNL-47610; R&D Project: PTHOPS; BnR: KA1401020; TRN: US0504988
- Journal Information:
- Physical Review D, Vol. 64; Related Information: Journal Publication Date: 2001
- Country of Publication:
- United States
- Language:
- English
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