One-Loop Analysis of FCNC Induced by Right-handed Down Squark Mixings

Abstract

If the underlying flavor symmetry is Abelian, quark mixings in $d_R$ sector are the most prominent. Such flavor violating effects can reveal itself through $\tilde d_R$ squark mixings if supersymmetry is realized in Nature. Quark-squark alignment is necessary to deal with $\Delta m_K$ and $\epsilon_K$ constraints, but interestingly, with $m_{\tilde q}$, $m_{\tilde g} \sim$ TeV, the $\tilde d_R$ mixing effects are comparable to $B_d$ and $B_s$ mixings in the Standard Model, while $D^0$ mixing is tantalizingly close to some hints from data. CP phases in these mixings would therefore be deviant, and $| V_{td}|$ and $\arg V_{ub}^*$ may be larger than allowed by unitarity constraints, which can be checked by the BaBar and Belle experiments. Mixing induced CP violation in $b\to s\gamma$ and $d\gamma$ transitions can be obtained, in particular, by sizable enhancement with an extra $\tan\beta$ factor from non-standard soft breaking terms. Heavy superparticles can escape present flavor changing neutral current (FCNC) bounds and direct searches at colliders, but reveal themselves in the B system.