Origin of CKM matrix and natural FCNC suppression in gauge-Higgs unification

In the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>S</a:mi><a:mi>O</a:mi><a:mo stretchy="false">(</a:mo><a:mn>5</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mn>1</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:mi>S</a:mi><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mn>3</a:mn><a:mo stretchy="false">)</a:mo></a:math> gauge-Higgs unification in the Randall-Sundrum warped space the mixing in the <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>W</i:mi></i:math> couplings in the quark sector is induced by masses of <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi>S</k:mi><k:mi>O</k:mi><k:mo stretchy="false">(</k:mo><k:mn>5</k:mn><k:mo stretchy="false">)</k:mo></k:math> singlet fermions which are responsible for splitting masses of down-type quarks from those of up-type quarks in each generation. We show that the observed Cabibbo-Kobayashi-Maskawa matrix in the <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mi>W</o:mi></o:math> couplings is reproduced within experimental errors. Further flavor-changing neutral currents in the quark sector are shown to be naturally suppressed.