Tetraquark Interpretation and Production Mechanism of the Belle $Y_b(10750)$-Resonance

Recently, the Belle Collaboration has updated the analysis of the cross sections for the processes $e^{+}{e}^{-}\to \mathrm{{\rm Y}}(nS){\pi }^{+}{\pi }^{-}$ ($n = 1,, 2,, 3$)inthe$e^+ e^-$ center-of-mass energy range from 10.52 to 11.02~GeV. A new structure, called $Y_b(10750)$, with the mass $M (Y_b) = (10752.7 \pm 5.9^{+0.7}{-1.1})$MeVandtheBreit-Wignerwidth$\Gamma (Y_b) = (35.5^{+17.6 +3.9}{-11.3 -3.3})$MeVwasobserved\mathrm{.}Weinterpret$Y_b (10750)$asacompact$J^{PC} = 1^{–}$ state with a dominant tetraquark component. The mass eigenstate $Y_b(10750)$ is treated as a linear combination of the diquark-antidiquark and $b\bar{b}$ components due to the mixing via gluonic exchanges shown recently to arise in the limit of large number of quark colors. The mixing angle between $Y_b$ and $\mathrm{{\rm Y}}(5S)$ can be estimated from the electronic width, recently determined to be $\Gamma_{ee} (Y_b) = (13.7 \pm 1.8)$eV\mathrm{.}Themixingprovidesaplausiblemechanismfor$Y_b (10750)$productioninhighenergycollisionsfromits$b \bar b$ component and we work out the Drell-Yan and prompt production cross sections for $p p \to Y_b (10750) \to \Upsilon (nS), \pi^+ \pi^-$ at the LHC. The resonant part of the dipion invariant mass spectrum in $Y_b(10750)\to \mathrm{{\rm Y}}(1S){\pi }^{+}{\pi }^{-}$ and the corresponding angular distribution of ${\pi }^{+}$-meson in the dipion rest frame are presented.