The gluonic decay of the b-quark and the η′-meson

Abstract

Abstract:The inclusive decay of B-mesons into η ′ + X is the consequence of the gluonic decay of the b-quark into an s-quark. As a result of the QCD anomaly this decay proceeds partly as the decay b → s + η ′ , similar to b → s + J/ψ. The hadronic recoiling system is found to have a relatively large mass. Analogously one expects a decay of the type b → s+σ.The branching ratios for these decays are large (of the order of 10 %). The results indicate that there is no room for an anomalously large chromomagnetic decay mode of the b-quark.Gluon jets are expected to exhibit an anomalously large tendency to fragment into η ′ -and σ-mesons.

Observation of High Momentumη′Production inBDecays

“…sg ‫ء‬ , g ‫ء‬ ! gh 0 from the h 0 QCD anomaly [6,[11][12][13][14]. The observed branching fraction is larger than what is expected from scenario I.…”

“…sg ‫ء‬ with g ‫ء‬ ! gh 0 from the QCD anomaly, which has the attractive feature that it accounts for the large mass of the h 0 relative to other members of its SU(3) multiplet, gives a threebody gsq mass spectrum that peaks above 2 GeV [6,[11][12][13][14] as shown in Fig. 2.…”

Constituent quarks and g 1

“…CLEO has measured the hard form-factors for the processes η → γγ * and η ′ → γγ * [83]. They have also observed strikingly large branching ratios for B decays into an η ′ and additional hadrons [84] 5 which may [85] be related to the axial anomaly. When combined with polarised deep inelastic scattering, these experiments on η and η ′ production and decay, provide complementary windows on the role of gluons in dynamical chiral symmetry breaking.…”

η′−g*−gtransition form factor with gluon content contribution tested

“…The large branching ratios of B → η ′ X s and B → η ′ K detected by CLEO [1,2] enhanced the importance of the QCD transition form factor F η ′ g * g ≡ H(q 2 1 , q 2 1 , m 2 η ′ ). The mechanisms using this transition form factor to explain these large decay rates are based on the b → sg * penguin transition followed by the decay g * → η ′ g [3][4][5][6][7][8] or on the transitions g * g * , g * g → η ′ [9,10]. The transition form factor F η ′ g * g being used are either extracted from the experimental data of ψ → η ′ γ [3,9,10], or based on phenomenological consideration [4,8], or calculated by assuming pseudoscalar coupling between η ′ and a quark pair [5].…”