Descrição: The problem of accounting for the degrees of freedom in passing from massive spin to massless helicity degrees of freedom and its inverse, the ``fattening'' of massless tensor fields to their massive $s=\left\vert h\right\vert $ counterparts, are solved using ``string-localized fields''. This approach allows to overcome the Weinberg-Witten impediment against the existence of massless $\left\vert h\right\vert \geq 2$ energy-momentum tensors, and to replace the van Dam-Veltman-Zakharov discontinuity concerning, e.g., very light gravitons, by a continuous limit $m\to0$.

Número: CBPF-NF-003/17