What is the notation for bounding running time in worst case with concrete example resulting in that worst case running time
In words, such a bound is called a tight bound. In the specific case of Landau notation, $\Theta$ can be used to indicate a tight bound.
You have to be somewhat careful about your wording, though:


"The runtime of quicksort is in $O(n^2)$," is a correct statement (but somewhat imprecise).
"The runtime of quicksort is in $O(n^2)$, and this bound is tight," is correct and expresses, what you want to express.
"The worst-case runtime of quicksort is in $\Theta(n^2)$," is equivalent to the previous statement.
But "The runtime of quicksort is in $\Theta(n^2)$," is not correct, since this statement implies that quicksort takes quadratic time on every input.