Dergi makalesi Açık Erişim

Study of the ${f}_{0}\left(980\right)$ and ${f}_{0}\left(500\right)$ Scalar Mesons through the Decay ${D}_{s}^{+}\to {\pi }^{+}{\pi }^{-}{e}^{+}{\nu }_{e}$

2024    CERN İşbirliği

Using ${e}^{+}{e}^{-}$ collision data corresponding to an integrated luminosity of $7.33\text{}\text{}{\mathrm{fb}}^{-1}$ recorded by the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV, we present an analysis of the decay ${D}_{s}^{+}\to {\pi }^{+}{\pi }^{-}{e}^{+}{\nu }_{e}$, where the ${D}_{s}^{+}$ is produced via the process ${e}^{+}{e}^{-}\to {D}_{s}^{*±}{D}_{s}^{\mp }$. We observe the ${f}_{0}\left(980\right)$ in the ${\pi }^{+}{\pi }^{-}$ system and the branching fraction of the decay ${D}_{s}^{+}\to {f}_{0}\left(980\right){e}^{+}{\nu }_{e}$ with ${f}_{0}\left(980\right)\to {\pi }^{+}{\pi }^{-}$ measured to be $\left(1.72±0.1{3}_{\mathrm{stat}}±0.1{0}_{\mathrm{syst}}\right)×{10}^{-3}$, where the uncertainties are statistical and systematic, respectively. The dynamics of the ${D}_{s}^{+}\to {f}_{0}\left(980\right){e}^{+}{\nu }_{e}$ decay are studied with the simple pole parametrization of the hadronic form factor and the Flatté formula describing the ${f}_{0}\left(980\right)$ in the differential decay rate, and the product of the form factor ${f}_{+}^{{f}_{0}}\left(0\right)$ and the $c\to s$ Cabibbo-Kobayashi-Maskawa matrix element $|{V}_{cs}|$ is determined for the first time to be ${f}_{+}^{{f}_{0}}\left(0\right)|{V}_{cs}|=0.504±0.01{7}_{\mathrm{stat}}±0.03{5}_{\mathrm{syst}}$. Furthermore, the decay ${D}_{s}^{+}\to {f}_{0}\left(500\right){e}^{+}{\nu }_{e}$ is searched for the first time but no signal is found. The upper limit on the branching fraction of ${D}_{s}^{+}\to {f}_{0}\left(500\right){e}^{+}{\nu }_{e}$, ${f}_{0}\left(500\right)\to {\pi }^{+}{\pi }^{-}$ decay is set to be $3.3×{10}^{-4}$ at 90% confidence level.