Using the entire data sample of $980\mathrm{f}{\mathrm{b}}^{-1}$ integrated luminosity collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we present an amplitude analysis measuring the branching fractions of the Cabibbo-allowed, $W$-exchange resonant decay ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0\varphi (\to K^{+}{K}^{-})$ with a polarized $\varphi$ and the nonresonant decay via a direct process ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0{K}^{+}{K}^{-}$. We present these measurements, relative to the normalization mode ${\mathrm{\Xi }}^{-}{\pi }^{+}$, and find branching ratios $\frac{\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0\varphi (\to K^{+}{K}^{-}))}{(\mathcal{B}{\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})}=0.036\pm 0.004(\mathrm{stat}.)\pm 0.002(\mathrm{syst}.)$ and $\frac{\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0{K}^{+}{K}^{-})}{\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})}=0.039\pm 0.004(\mathrm{stat}.)\pm 0.002(\mathrm{syst}.)$, which suggest that only minor cusping peaks occur in the combinatorial background of ${\mathrm{\Omega }}^{*-}\to {\mathrm{\Xi }}^0{K}^{-}$ due to these ${\mathrm{\Xi }}_c^0$ decays.

• Received 11 December 2020
• Accepted 10 May 2021

DOI:https://doi.org/10.1103/PhysRevD.103.112002

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society