$B\to ϕπ$ and $B^0 \to ϕϕ$ in the Standard Model and new bounds on R parity violation

Abstract

We study the pure penguin decays $B \to ϕπ$ and $B^0 \to ϕϕ$. Using QCD factorization, we find ${\cal B}(B^\pm \toϕπ^{\pm} )=2.0^{+0.3}_{-0.1}\times 10^{-8}$. For the pure penguin annihilation process $B^0 \to ϕϕ$, analyzed here for the first time, ${\cal B}(B^0 \toϕϕ)=2.1^{+1.6}_{-0.3}\times 10^{-9}$. The smallness of these decays in the Standard Model makes them sensitive probes for new physics. From the upper limit of $B\to ϕπ$,we find constraints on R parity violating couplings, $| λ{''}_{i23}λ{''}_{i21}|<6\times10^{-5}$, $| λ'_{i23}λ'_{i21}|<4\times10^{-4}$ and $| λ'_{i32}λ'_{i12}|<4\times10^{-4}$ for $i=1,2,3$. Our new bounds on $|λ{''}_{i23}λ{''}_{i21}|$ are one order of magnitude stronger than before. Within the available upper bounds for $| λ{''}_{i23}λ{''}_{i21}|$, $|λ'_{i23}λ'_{i21}|$ and $|λ'_{i32}λ'_{i12}|$, we find that ${\cal B}(B\toϕϕ)$ could be enhanced to $10^{-8}\sim 10^{-7}$. Experimental searches for these decays are strongly urged.