Determination of closed-flavour πJ/ψ and πϒ cross sections at low energies from dipion decays

Abstract

The scale of low energy cc and bb cross sections on light hadrons is of great importance to searches for the quark gluon plasma using the heavy-quarkonium suppression signature. Unfortunately, little is known about these near-threshold cross sections at present, and recent theoretical estimates span many orders of magnitude. Here we use experimental data on the four observed closed-flavor heavy quarkonium hadronic decays ψ ′ → ππJ/ψ, Υ ′ → ππΥ, Υ ′′ → ππΥ and Υ ′′ → ππΥ ′ , combined with simple models of the transition amplitudes, to estimate the pion scattering cross sections of cc and bb mesons near threshold. Specifically we consider the closed-flavor reactions πJ/ψ → πψ ′ , πΥ → πΥ ′ , πΥ → πΥ ′′ and πΥ ′ → πΥ ′′ and their time-reversed analogues. Our results may be useful in constraining theoretical models of the strong interactions of heavy quarkonia, and can be systematically improved through future detailed studies of dipion decays, notably ψ ′ → ππJ/ψ and Υ ′′ → ππΥ.

Charmonium production inpp¯annihilation: Estimating cross sections from decay widths

“…Note that in this approximation all the energy dependence in the cross section comes from the expression in square brackets. A similar approach has been used to estimate charmonium cross sections of relevance to QGP experiments [11].…”

“…f (β) (11) where β = β π β p , γ = γ π γ p and f (x) = tanh −1 (x)/x. The coupling σ CP is a linear combination of these ξ functions.…”

K*-charmonium dissociation cross sections and charmonium dissociation rates in hadronic matter

“…Up to now, attempts to constrain theoretical models about πJ/ψ → πψ ′ have been made in Refs. [38][39][40] from the experimental data on the hadronic decay ψ ′ → ππJ/ψ. We can not use the cross sections obtained in Refs.…”

“…We can not use the cross sections obtained in Refs. [38][39][40] for πJ/ψ → πψ ′ to constrain our charmonium dissociation cross sections since the reaction can not be studied in the quark-interchange mechanism. However, we can use the experimental data on elastic ππ scattering for I = 2 and elastic πK scattering for I = 3/2 to examine our cross sections for πJ/ψ, πχ c , and πψ ′ dissociation.…”