$D$ wave bottomonia production from $Z_b^{(\prime)}$ decay

Abstract

In the present work, we investigate the dipion transitions between Υ(5S ) and Υ J (1D) with J = 1, 2, 3. Our analysis indicates that the dominant sources of the anomalously large widths of Υ(5S ) → Υ J (1D)π + π − should be Z (′) b , i.e., the dipion transitions occur via the cascade decays Υ(5SWith the assumption that all the short ranged dynamics could be absorbed in a single cutoff with a model parameter α, the present estimations indicate that in a reasonable parameter range the measured branching ratios of Υ(5S ) → Υ J (1D)π + π − can be reproduced in magnitude, which further proves that the decays via Z (′) b dominate the dipion transitions of Υ(5S ) to Υ J (1D). Moreover, we also predict the ratios of the branching fractions of Z (′) b → Υ J (1D)π, which in our calculations are largely independent of the parameter α and could be tested by further experiments in Belle II.