Let $H_{j} := (H_{j}, \| \cdot \|_{H_{j}} ), j=0,1$ be a Hilbert space, and set \begin{equation*} {\mathscr S}'(\mathbb{R}^{n}, H_0; H_1) := {\mathscr L}( {\mathscr S}(\mathbb{R}^{n}, H_0), H_1) \end{equation*} where ${\mathscr S}(\mathbb{R}^{n}, H_0)$ denotes the space of Schwartz functions $\phi \colon \mathbb{R}^{n} \to H_0$. (Bergh & Lofstrom's book: Interpolation Spaces, page 134)

Then clearly ${\mathscr S}(\mathbb{R}^{n}, {\mathscr L}(H_0,H_1)) \subset L^{p}(\mathbb{R}^{n}, {\mathscr L}(H_0,H_1)) \subset {\mathscr S}'(\mathbb{R}^{n}, H_0; H_1)$.

I wonder whether the Paley-Wiener-Schwartz theorem can be extended to this space of vector-valued tempered distributions. I imagine a statement like this one:

**Theorem:** An entire analytic fucntion $U \colon \mathbb{C}^{n} \to {\mathscr L}(H_0,H_1)$ is the Fourier-Laplace transform of a distribution $u \in {\mathscr E}'(\mathbb{R}^{n}, H_0; H_1)$ with support in the ball $B[0,R]$ if and only if for some positive constants $c$ and $N$ we have $\| U(\zeta) \|_{{\mathscr L}(H_0,H_1)} \leqslant c (1+|\zeta|)^{N}\exp(R |Im \, \zeta|)$, for every $\zeta \in \mathbb{C}^{n}$.

Here, ${\mathscr E}'(\mathbb{R}^{n}, H_0; H_1):={\mathscr L}( C^{\infty}(\mathbb{R}^{n}, H_0), H_1)$, unsurprisingly.

I could not do it because I do not know how convolutions can be defined in this context and be used to obtain density results that appear in the proof of Paley-Wiener-Schwartz theorem.

Is there some good reference for vector-valued distributions as defined above? Bergh & Lofstrom is too succinct and does not provide a reference for this subject, particularly.