Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation
Abstract
Assuming the dominance of the spin-spin interaction in a diquark, we point out that the mass difference in the beauty sector M(Z_b^prime) - M(Z_b) scales with quark masses as expected in QCD, with respect to the corresponding mass difference M(Z_c^prime) - M(Z_c). Notably, we show that the decays Upsilon(10890) --> Upsilon(nS) pi pi and Upsilon(10890) --> (h_b(1P), h_b(2P)) pi pi are compatible with heavy-quark spin conservation if the contributions of Z_b,Z_b^prime intermediate states are taken into account, Upsilon(10890) being either a Upsilon(5S) or the beauty analog of Y_c(4260). Belle results on these decays support the quark spin wave-function of the Z states as tetraquarks. We also consider the role of light quark spin non-conservaton in Z_b,Z_b^prime decays into B B^* and B^* B^*. Indications of possible signatures of the still missing X_b resonance are proposed.
Cite
@article{arxiv.1412.2049,
title = {Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation},
author = {A. Ali and L. Maiani and A. D. Polosa and V. Riquer},
journal= {arXiv preprint arXiv:1412.2049},
year = {2015}
}
Comments
5 pages, comments added, to appear in Phys Rev D