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

Abstract

Using a data sample of $4.48×10^8$ $\psi(3686)$ events collected with the BESIII detector, we present a first observation of $\psi(3686)\to p\bar{p}\phi$, and we measure its branching fraction to be [6.06±0.38(stat.)±0.48(syst.)]×10$^{−6}$. In contrast to the earlier discovery of a threshold enhancement in the $p\bar{p}$-mass spectrum of the channel $J/\psi\to\gamma p\bar p$, denoted as $X(p\bar{p})$, we do not find a similar enhancement in $\psi(3686)\to p\bar{p}\phi$. An upper limit of 1.82×10$^{−7}$ at the 90% confidence level on the branching fraction of $\psi(3686)\to X(p\bar{p})\phi\to p\bar{p}\phi$ is obtained.