The numerical radius Haagerup norm and Hilbert space square factorizations

We study a factorization of bounded linear maps from an operator space $A$ to its dual space $A^{\ast }$. It is shown that $T:A⟶A^{\ast }$ factors through a pair of a column Hilbert spaces ${\mathcal{H}}_c$ and its dual space if and only if $T$ is a bounded linear form on $A\otimes A$ by the canonical identification equipped with a numerical radius type Haagerup norm. As a consequence, we characterize a bounded linear map from a Banach space to its dual space, which factors through a pair of Hilbert spaces.