Anomalous Higgs Yukawa couplings

Abstract

In the standard model, the Higgs boson $h$ couples to the quarks and charged\nleptons according to the well-known formula $(m_\\psi/v) h \\bar{\\psi}\\psi$,\nwhere $\\psi$ = quark (q) or lepton (l) and $v$ = 246 GeV is its vacuum\nexpectation value. Suppose $m_\\psi$ is of radiative origin instead, then the\neffective $h \\bar{\\psi}\\psi$ Yukawa coupling will not be exactly $m_\\psi/v$. We\nshow for the first time quantitatively how this may shift the observed\nbranching fraction of $h \\to \\bar{b}b$ and $h \\to \\tau^+ \\tau^-$ upward or\ndownward. Thus the precision measurements of Higgs decay to fermions at the\nLarge Hadron Collider, due to resume operation in 2015, could be the key to\npossible new physics.\n