Eur. Phys. J. C 24, 159-164 (2002)
https://doi.org/10.1007/s100520200910

Top--bottom mass hierarchy, s - µ puzzle and gauge coupling unification with split multiplets

¹ School of Physics, Korea Institute for Advanced Study, Cheongryangri-dong, Dongdaemun-ku, Seoul 135-012, Korea
² School of Physics and Center for Theoretical Physics, Seoul National University, Seoul 151-747, Korea

Corresponding authors: ^a hdkim@kias.re.kr - ^b jekim@phyp.snu.ac.kr - ^c minlee@phya.snu.ac.kr

Received: 10 December 2001
Revised: 22 January 2002
Published online: 5 April 2002

Abstract

Supersymmetric 5D SU(5) grand unification is considered. SU(5) is broken down to G_SM = SU(3) × SU(2) × U(1) by the Z₂ × Z₂' assignment of the bulk field(s). The matter fields are located at the fixed point(s). In the bulk, a Higgs multiplet ͞5_H (containing the bottom doublet H₁) and the SU(5) gauge multiplet are located. At one fixed point, H₂ (the top doublet) and the standard model matter multiplets are presented. Because of the difference of the locations of H₁ and H₂, one can obtain a hierarchy between top and bottom Yukawa couplings. We also present a possible way to understand the s–µ mass puzzle in this framework of the split multiplet.