2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194720It was argued long ago that eta_b could be observed through the eta_b => Jpsi(=> mu+ mu-) Jpsi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta_b into two Jpsi is almost 3 orders of magnitude smaller than the one into the D bar D*. We study the effects of final-state interactions due to the D bar D* intermediate state on the Jpsi Jpsi final state. We find that the inclusion of this contribution may enhance the short-distance branching ratio up to about 2 orders of magnitude.4 pages, 3 figures. The estimate of the dispersive contribution was added. Typos corrected. To be published in Phys. Rev. DHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext