Observation of $psi(3686)to pbar{p}phi$

Using a data sample of $4.48times10^{8}$ $psip$ events collected with the BESIII detector, we present a first observation of $psi(3686)to pbar{p}phi$, and we measure its branching fraction to be $[6.06pm0.38 ($stat.$) pm 0.48 ($syst.$)]times10^{-6}$. In contrast to the earlier discovery of a threshold enhancement in the $pbar{p}$-mass spectrum of the channel $J/psitogamma pbar p$, denoted as $X(pbar{p})$, we do not find a similar enhancement in $psi(3686)to pbar{p}phi$. An upper limit of $1.82times10^{-7}$ at the $90%$ confidence level on the branching fraction of $psi(3686)to X(pbar{p})phito pbar{p}phi$ is obtained.