Search for light tetraquark states in $\mathrm{{\rm Y}}(1S)$ and $\mathrm{{\rm Y}}(2S)$ decays

We search for the $J^{PC}=0^{--}$ and $1^{+-}$ light tetraquark states with masses up to 2.46~GeV/$c^2$ in $\mathrm{{\rm Y}}(1S)$ and $\mathrm{{\rm Y}}(2S)$ decays with data samples of $(102\pm 2)$ million and $(158\pm 4)$ million events, respectively, collected with the Belle detector. No significant signals are observed in any of the studied production modes, and 90% credibility level (C.L.) upper limits on their branching fractions in $\mathrm{{\rm Y}}(1S)$ and $\mathrm{{\rm Y}}(2S)$ decays are obtained. The inclusive branching fractions of the $\mathrm{{\rm Y}}(1S)$ and $\mathrm{{\rm Y}}(2S)$ decays into final states with $f_1(1285)$ are measured to be ${\cal B}(\Upsilon(1S)\to f_1(1285)+anything)=(46\pm28({\rm stat.})\pm13({\rm syst.}))\times 10^{-4}$and${\cal B}(\Upsilon(2S)\to f_1(1285)+anything)=(22\pm15({\rm stat.})\pm6.3({\rm syst.}))\times 10^{-4}$. The measured ${\chi }_{b2}\to J\mathrm{/}\psi +anything$ branching fraction is measured to be $(1.50\pm 0.34(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{.})\pm 0.22(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{.}))\times {10}^{-3}$, and 90% C.L. upper limits for the ${\chi }_{b0,b1}\to J\mathrm{/}\psi +anything$ branching fractions are found to be $2.3\times {10}^{-3}$ and $1.1\times {10}^{-3}$, respectively. For $\mathcal{B}({\chi }_{b1}\to \omega +anything)$, the branching fraction is measured to be $(4.9\pm1.3({\rm stat.})\pm0.6({\rm syst.}))\times 10^{-2}$\mathrm{.}$<3.68\times 10^{-2}$ at 90% C.L.). All results reported here are the first measurements for these modes.