Interpretation of Yb(10750) as a tetraquark and its production mechanism

Recently, the Belle Collaboration has updated the analysis of the cross sections for the processes e(+)e(-) -> Upsilon(nS) pi(+)pi(-) (n = 1, 2, 3) in the e(+)e(-) center-of-mass energy range from 10.52 to 11.02 GeV. A new structure, called here Y-b (10750), with the mass M(Y-b) = (10752.7 +/- 5.9(-1.1)(+0.7)) MeV and the Breit-Wigner width Gamma(Y-b) = (35.5(-11.3-3.3)(+17.6+3.9)) MeV was observed [I]. We interpret Y-b(10750) as a compact 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 (b) over bar 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 Upsilon(5S) can be estimated from the electronic width, recently determined to be Gamma(ee)(Y-b) = (13.7 +/- 1.8) eV. The mixing provides a plausible mechanism for Y-b (10750) production in high energy collisions from its b (b) over bar component and we work out the Drell-Yan and prompt production cross sections for pp -> Y-b (10750) -> Upsilon(nS) pi(+)pi(-) at the LHC. The resonant part of the dipion invariant mass spectrum in Y-b (10750) -> Upsilon(1S)pi(+)pi(-) and the corresponding angular distribution of pi(+)-meson in the dipion rest frame are presented as an example. (C) 2020 The Authors. Published by Elsevier B.V.