Common origin of the Belle-BESIII line-shape difference of ${\mathrm{\Lambda }}_c^{+}{\bar{\mathrm{\Lambda }}}_c^{-}$, $D_s{D}_{s1}$ and $D_s{D}_{s2}^{\ast }$ from $e^{+}{e}^{-}$ annihilation

The longstanding Belle–BESIII discrepancies in the $e^{+}{e}^{-}\to {\mathrm{\Lambda }}_c^{+}{\bar{\mathrm{\Lambda }}}_c^{-}$, $D_s{D}_{s1}(2536)$, and $D_s{D}_{s2}^{\ast }(2573)$ line shapes remain an unresolved puzzle, with enhancements observed by Belle that are absent or much weaker in the BESIII measurements. In this work, we propose a new mechanism based on the radiative production of higher charmonia to explain these differences. Such processes may contribute to Belle’s initial-state radiation samples, and the luminosity normalization increases their contribution to the extracted cross sections. With the vector contributions scaled by BESIII data, a pseudoscalar charmonium ${\eta }_c(6S)$ contribution can describe the baryonic enhancement, while an introduced ${\chi }_{c2}(5P)$ contribution can describe the enhancements in both meson channels. This mechanism offers a possible common explanation for these differences and, as a bonus, suggests a way to search for missing higher charmonia at Belle II.