We search, for the first time, for an exotic molecular state with quantum numbers $J^{ PC}=1^{ -+}$, called $X$, via the process $e^{ +}e^{ -} \to \gamma D^{ +}_{ s} D_{ s1}^{ -}(2536) +c.c.$ using data samples corresponding to a luminosity of $5.8~\mathrm{ fb^{ -1}}$ across center-of-mass energies from 4.612 to 4.951~GeV, collected with the BESIII detector operating at the BEPCII collider. No statistically significant signal is observed. The upper limits on the product of cross-section and branching fraction $\sigma({ e^{ +}e^{ -} \to \gamma X}) \times \mathcal{ B}(X \to D^{ +}_{ s} D_{ s1}^{ -}(2536) +c.c.)$ at 90\% confidence level are reported for each energy point, assuming the $X$ mass to be 4.503~GeV/$c^{ 2}$ and the width 25, 50, 75, and 100~MeV, respectively.
Categories: hep-ex