Gauge coupling and fermion mass relations in low string scale brane models

D. V. Gioutsos, G. K. Leontaris, J. Rizos
2006 European Physical Journal C: Particles and Fields  
We analyze the gauge coupling evolution in brane inspired models with U(3) × U(2) × U(1)^N symmetry at the string scale. We restrict to the case of brane configurations with two and three abelian factors (N=2,3) and where only one Higgs doublet is coupled to down quarks and leptons and only one to the up quarks. We find that the correct hypercharge assignment of the Standard Model particles is reproduced for six viable models distinguished by different brane configurations. We investigate the
more » ... ird generation fermion mass relations and find that the correct low energy m_b/m_τ ratio can be obtained for b-τ Yukawa coupling equality at a string scale as low as M_S ∼ 10^3 TeV.
doi:10.1140/epjc/s2005-02411-x fatcat:uw7pln4d7vgyjdnp7r3typkpii