Flavour violating gluino three-body decays at LHC

We study the effect of squark generation mixing on gluino production and decays at LHC in the Minimal Supersymmetric Standard Model (MSSM) for the case that the gluino is lighter than all squarks and dominantly decays into three particles, g → q q χ0k, q anti q'χ±l. We assume mixing between the second and the third squark generations in the up-type and down-type squark sectors. We show that this mixing can lead to very large branching ratios of the quark-flavour violating gluino threebody decays despite the strong constraints on quark-flavour violation (QFV) from the experimental data on B mesons. We also show that the QFV gluino decay branching ratios are very sensitive not only to the generation mixing in the squark sector, but also to the parameters of the neutralino and chargino sectors. We show that the branching ratio of the QFV gluino decay g → c anti t(anti ct) anti χ01 can go up to ∼ 40%. Analogously, that of the QFV decay g → s anti b(anti sb)χ01 can reach ∼ 35%. We find that the rates of the resulting QFV signatures, such as pp→ tt anti c anti cEmisT, can be significant at LHC. This could have an important influence on the gluino searches at LHC. (orig.)