Search for a strangeonium-like structure $Z_s$ decaying into $\phi \pi$ and a measurement of the cross section $e^+e^-\rightarrow\phi\pi\pi$

Abstract

Using a data sample of $e^+e^−$ collision data corresponding to an integrated luminosity of 108 pb −1 collected with the BESIII detector at a center-of-mass energy of 2.125 GeV, we study the process $e^+e^-\rightarrow \phi\pi\pi$ and search for a strangeonium-like structure $Z_s$ decaying into $\phi\pi$. No signal is observed in the $\phi\pi$ mass spectrum. Upper limits on the cross sections for $Z_s$ production at the 90% confidence level are determined. In addition, the cross sections of $e^+e^-\rightarrow\phi\pi^{+}\pi^{-}$ and $e^+e^-\rightarrow\phi\pi^{0}\pi^{0}$ at 2.125 GeV are measured to be (436.2±6.4±30.1) pb and (237.0±8.6±15.4) pb, respectively, where the first uncertainties are statistical and the second systematic.