Two-γdecay widths of glueballs

Abstract

Using a nonrelativistic gluon bound-state model, we compute T( G -yy), where G is a pseudoscalar, tensor, or scalar digluon, starting from the amplitudes of the process y y -g *g * at threshold, the g *'s being massive constituent gluons. Those amplitudes are obtained, at lowest order in perturbative QCD, by deriving them from a QED calculation performed many years ago by Constantini, de Tollis, and Pistoni. The unknown parameter (the digluon wave function, or its first or second derivative, at the origin) is determined by using measured values of T(J/$-+Gy). Our predictions are compared, for various glueball candidates, with present experimental limits.

Glueballs in peripheral heavy-ion collisions

“…Partial widths for other states can also be found in Ref. [13]. We will compute the production rates only for η(1440) and f 2 (1720), and with the average values of Ref.…”

Glueball production in radiativeJ/ψ,Υdecays

“…We limit ourselves to summarize the main steps of our approach. The interested reader will find more details in Ref.s [10][11][12][13], where the same approach was formulated and applied to several hadronic production/decay processes at high energy scales.…”

“…To this end, we use an approach previously developed by some of us and already applied to several processes involving the production and/or decay of hadronic states (including qq mesons and two-gluon bound states) at high energies [10][11][12][13]. This approach is a generalization of the formalism developed, starting from the early 80's, in the framework of perturbative QCD for the study of exclusive hadronic processes at high transfer momentum [14].…”

“…[10], in the case of a nonrelativistic distribution amplitude for the two-gluon bound state. Here we extend and generalize the analysis to the case of a generic glueball distribution amplitude; we also present analytical and numerical results obtained using several different models for the glueball distribution amplitude.…”

Glueball production in high-energy collisions

“…In order to be able to treat the case of digluons with any value of L (in particular L =0, 1, or 21, we here use an extension of the nonrelativistic gluon bound-state model, previously applied to the computation of 2y decay widths of glueballs [4]. That extended model is exhibited in Sec.…”