Nonplanar 4-Jets in Quarkonium Decays as a Probe for 3-Gluon Coupling

Abstract

We calculate the acoplanarity (à la Fox-Wolfram) distribution of 4 jets generated by orthoquarkonium decays: . The result shows that the deviation from planar event due to 4 jets is significantly large showing the importance of the effect of 3-gluon couplings in quantum chromodynamics. The average acoplanarity 〈D〉 is calculated to be 〈D〉 = (0.45 + 0.153Nf)αs/π with Nf the number of flavors of produced quarks and αs the QCD coupling strength. As a by-product we calculated the decay rate of the parapositronium into 4 photons which results in Γ4γ = (0.0139±0.0001)α7me with me the electron mass.