A Phenomenological Analysis of Gluon Mass Effects in Inclusive Radiative Decays of the J / ψ and Υ
نویسنده
چکیده
The shapes of the inclusive photon spectra in the processes J/ψ → γX and Υ → γX have been analysed using all available experimental data. Relativistic, higher order QCD and gluon mass corrections were taken into account in the fitted functions. Only on including the gluon mass corrections, were consistent and acceptable fits obtained. Values of 0.721 −0.29 GeV were found for the effective gluon masses (corresponding to born level diagrams) for the J/ψ and Υ respectively. The width ratios Γ(V → hadrons)/Γ(V → γ + hadrons) V = J/ψ, Υ were used to determine α s (1.5GeV) and α s (4.9GeV). Values consistent with the current world average α s were obtained only when gluon mass correction factors, calculated using the fitted values of the effective gluon mass, were applied. A gluon mass ≃ 1 GeV, as suggested with these results, is consistent with previous analytical theoretical calculations and independent phenomenological estimates, as well as with a recent, more accurate, lattice calculation of the gluon propagator in the infra-red region.
منابع مشابه
Dynamical gluon mass corrections in heavy quarkonia decays
Using the expression of the dynamical gluon mass obtained through the operator product expansion we discuss the relevance of gluon mass effects in the decays V → hadrons (V = J/ψ, Υ). Relativistic and radiative corrections are also introduced to calculate αs(mc) and αs(mb) comparing them with other values available in the literature. The effects of dynamical gluon masses are negligible for Υ de...
متن کاملThe Resummed Photon Spectrum in Radiative Upsilon Decays (And More)
In this talk I present the results of two calculations that make use of Non-Relativistic QCD and the newly developed Soft-Collinear Effective Theory. The first process considered is inclusive radiative Υ decay. The second process considered is the leading color-octet contribution to e+e− → J/ψ + X . Bound states of heavy quarks and antiquarks have been of great interest since the discovery of t...
متن کاملQuarkonium chromo - polarizability from the decays
It is pointed out that the diagonal amplitude of the E1 − E1 chromo-electric interaction with soft gluon fields (chromo-polarizability) can be measured directly for the J/ψ and Υ resonances in the decays J/ψ → ππℓ + ℓ − and Υ → ππℓ + ℓ − with soft pions. For the J/ψ this amplitude is often discussed in connection with the J/ψ interaction with nuclear matter, while for the Υ the chromo-polarizab...
متن کاملThe contribution of the J/ψ resonance to the radiative B decays
The radiative decays of the B mesons may have a significant contribution from the transition b → sJ/ψ followed by the J/ψ-photon conversion. The size of this contribution is re-analysed in the light of a phenomenological model for the weak bsJ/ψ vertex, and a modified J/ψ-photon interaction that is manifestly gauge invariant. Predictions for both inclusive and exclusive cases are obtained, but ...
متن کاملRadiative Decay of Υ into a
We study the radiative decay of Υ into a scalar glueball Υ → γGs using QCD factorization. We find that for this process the non-perturbative effects can be factorized into a matrix element defined in non-relativistic QCD which can be determined from leptonic decay of Υ, and into the gluon parton distribution amplitude, whose asymptotic form is known up to a normalization constant. Normalizing t...
متن کامل