Measurements of Normalized Differential Cross Sections of Inclusive $\eta $ Production in ${e}^{+}{e}^{-}$ Annihilation at Energy from 2.0000 to 3.6710 GeV

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, the cross section of the inclusive process ${e}^{+}{e}^{-}\to \eta +X$, normalized by the total cross section of ${e}^{+}{e}^{-}\to \text{hadrons}$, is measured at eight center-of-mass energy points from 2.0000 to 3.6710 GeV. These are the first measurements with momentum dependence in this energy region. Our measurement shows a significant discrepancy compared to the existing fragmentation functions. To address this discrepancy, a new QCD analysis is performed at the next-to-next-to-leading order with hadron mass corrections and higher twist effects, which can explain both the established high-energy data and our measurements reasonably well.