Using $\overline{p}p$ and $e^{+}{e}^{-}$ annihilation data to refine bounds on the baryon-number-violating dinucleon decays $nn\to e^{+}{e}^{-}$ and $nn\to {\mu }^{+}{\mu }^{-}$

We use $\overline{p}p$ and $e^{+}{e}^{-}$ annihilation data to further strengthen lower bounds on the partial lifetimes for the baryon-number-violating dinucleon decays $nn\to e^{+}{e}^{-}$ and $nn\to {\mu }^{+}{\mu }^{-}$. These bounds are of interest since baryon number violation is expected to occur in nature and is predicted in many theories beyond the Standard Model.