Penguin-diagram-inducedB→KXφdecays in the standard model and in the two-Higgs-doublet model

We systematically analyze the gluonic penguin-diagram-induced charmless decays $B\to K_X\phi$ [$K_X$ denotes the meson state $s\overline{q}$ ($q=u or d$)], in the standard model and the two-Higgs-doublet model. These processes, being induced at the one-loop level, are of great importance in measuring the virtual top quark effect in the standard model, and also in searching for the nonstandard signals in the low energy region. It is shown that the QCD effect is also significant in these processes, as in the weak radiative processes $B\to X_s\gamma$. We also show that the charged Higgs contribution cannot provide sizable enhancements for the decays $B\to K_X\phi$, in contrast with the decays $B\to K_X\gamma$. It is also found that processes such as $B\to K_1\mathrm{}\left(1400\right)\mathrm{}\phi$ and $B\to K\left(1460\right)\mathrm{}\phi$ have large branching fractions among $B\to K_X\phi$ decays.