The processes $e^+e^-\rightarrow b\bar bW^\pm H^\mp$ and $e^+e^-\rightarrow b\bar bH^+H^-$ at the next linear collider in the minimal supersymmetric standard model

Abstract.

The complete matrix elements for $e^+e^-\rightarrow b\bar bW^\pm H^\mp$ and $e^+e^-\rightarrow b\bar bH^+H^-$ are computed at tree-level within the Minimal Supersymmetric Standard Model. Rates of interest to phenomenological analyses at the Next Linear Collider are given. In particular, we analyse: (i) $t\bar t$ pair production followed by the top decays into $b\bar bW^\pm H^\mp$ and $b\bar b H^+H^-$ final states; (ii) $H^+H^-$ signals in which $H^\pm\to h W^{\pm} \to b\bar b W^{\pm}$ and $H^\pm\to tb\to b\bar b W^\pm$. Top and Higgs finite width effects are included as well as all those due to the irreducible backgrounds.