   $t\bar{t}$ (SL)   $t\bar{t}$ (LL)   $Wb\bar{b}$   $Zb\bar{b}$   $t\bar{t}b\bar{b}$ (SL)   $t\bar{t}b\bar{b}$ (LL)   --------------- -------- ----------------- ----------------- ------------- ------------- ------------------------- -------------------------         