Hadronic decays of excited heavy quarkonia

Abstract

We construct an effective Lagrangian for the hadronic decays of a heavy excited s-wave-spin-one quarkonium into its ground state. We show that reasonable fits to the measured invariant mass spectra in the J/ψ and Υ systems can be obtained working in the chiral limit. The mass dependence of the various terms in the Lagrangian is discussed on the basis of a quark model.

Study of dipion transitions amongΥ(3S),Υ(2S), andCronin-Hennessy1, Gao2, Hietala3 et al. 2007Phys. Rev. D

“…Neglecting the dependence on the parent and final state Upsilon polarizations (which apply only to the C term), we have only two degrees of freedom, the Dalitz variables q 2 M 2 and r 2 M 2 . In writing this amplitude, we have assumed the chiral limit, so that a fourth term, gM 2 , is taken to be zero [26,27].…”

Comment on the hadronic decay of excited heavy quarkonia

“…By using this Lagrangian, the authors of ref. [1] have obtained a good fit to the data, especially to ψ −→ J/ψππ, Υ(2S) −→ Υ(1S)ππ and Υ(3S) −→ Υ(1S)ππ. However, they do not present a correct partial wave analysis to the decay amplitudes.…”

“…An effective Lagrangian for these exclusive hadronic decays has been constructed in [1]. It is of as follows…”

On the structure of the ππ invariant mass spectra of the ϒ(4S)→ϒ(1S,2S)π+Guo1, Shen2, Chiang3 et al. 2007Physics Letters B12030View full textAdd to dashboardCite

“…In past years, much attention has been attracted to such a phenomenon [7,8,9,10,11,12,13]. Now, the reported π + π − invariant mass spectrum of the Υ(4S) → Υ(2S)π + π − decay also exhibits a distinguishable double peak structure, but in the Υ(4S) → Υ(1S)π + π − decay, the lower structure seems not evident [2,4,14].…”

“…Among low partial waves between two pions, only S-and D-waves can contribute to the decay amplitude. Because the contribution from the D-wave is suppressed by a factor of 2/45 due to the integration of the 2nd order Legendre polynomial, the squared decay amplitude can be approximated by the By incorporating appropriately the chiral expansion with the heavy quark expansion to the lowest order, the amplitude of the contact term in the heavy quarkonium π + π − transition can be written as [11,13,16]…”