  A modular representation for the semileptonic decays of baryons originating
from spin polarized and correlated baryon-antibaryon pairs is derived. The
complete spin information of the decaying baryon is propagated to the daughter
baryon via a real-valued matrix. It allows to obtain joint differential
distributions in sequential processes involving the semileptonic decay in a
straightforward way. The formalism is suitable for extraction of the
semileptonic formfactors in experiments where strange-baryon-antibaryon pairs
are produced in electron-positron annihilation or in charmonia decays. We give
examples such as the complete angular distributions in the $e^+e^-\to
\Lambda\bar\Lambda$ process, where $\Lambda\to pe^-\bar{\nu}_e$ and
$\bar\Lambda\to\bar{p}\pi^+$. The formalism can also be used to describe the
distributions in semileptonic decays of charm and bottom baryons. Using the
same principles, the modules to describe electromagnetic and neutral current
weak baryon decay processes involving a charged lepton-antilepton pair can be
obtained. As an example, we provide the decay matrix for the Dalitz transition
between two spin-1/2 baryons.
