CKM matrix and FCNC suppression in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi><mml:mi>O</mml:mi><mml:mo mathvariant="bold" stretchy="false">(</mml:mo><mml:mn>5</mml:mn><mml:mo mathvariant="bold" stretchy="false">)</mml:mo><mml:mo>×</mml:mo><mml:mi>U</mml:mi><mml:mo mathvariant="bold" stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:mo mathvariant="bold" stretchy="false">)</mml:mo><mml:mo>×</mml:mo><mml:mi>S</mml:mi><mml:mi>U</mml:mi><mml:mo mathvariant="bold" stretchy="false">(</mml:mo><mml:mn>3</mml:mn><mml:mo mathvariant="bold" stretchy="false">)</mml:mo></mml:math> gauge-Higgs unification
Shuichiro Funatsu, Hisaki Hatanaka, Yutaka Hosotani, Yuta Orikasa, Naoki Yamatsu
Abstract
The Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix and flavor-changing neutral currents (FCNCs) in the quark sector are examined in the grand unified theory inspired $SO(5)\ifmmode\times\else\texttimes\fi{}U(1)\ifmmode\times\else\texttimes\fi{}SU(3)$ gauge-Higgs unification in which the 4D Higgs boson is identified with the Aharonov-Bohm phase in the fifth dimension. Gauge invariant brane interactions play an important role for the flavor mixing in the charged-current weak interactions. The CKM matrix is reproduced except that the up quark mass needs to be larger than the observed one. FCNCs are naturally suppressed as a consequence of the gauge invariance, with a factor of order ${10}^{\ensuremath{-}6}$. It is also shown that induced flavor-changing Yukawa couplings are extremely small.