O(α_sv~2) correction to J/ψ plus η_c production in e~+e~- annihilation at √s=10.6 GeV

Based on the nonrelativistic QCD factorization approach, O(α_sv2) corrections to J/ψ plus η_c production in m e⁺e^- annihilation at √s=10.6 ≥v are calculated in this work. The numerical results show that the correction at α_sv2 order is only about a few percent of the total theoretical result. This indicates that the perturbative expansions become convergent and that a higher order correction will be smaller. The uncertainties from the long-distance matrix elements, renormalization scale and the measurement in the experiment are also discussed. Our result is in agreement with the previous result by Jia.     

J/ψ inclusive production in χbJ（nP） decays

We study J/ψ inclusive production in the decays of P-wave bottomonium χbJ（1P,2P） for J=0,1,2. Within the framework of the non-relativistic QCD（NRQCD） factorization method we calculate the contri-butions coming from four relevant processes including one color-singlet process and three color-octet ones,which are b（3PJ,1） → c（3S1,8） ＋ c ＋,b（3S1,8） → c（3S1,1） ＋ g ＋ g,b（3S1,8） → c（3S1,1） ＋ c ＋ and b（3S1,8） → c（3S1,8） ＋g. Our calculation shows that the color-octet processes,especially the gluon fragmen-tation one,contribute the most in the decays of χb0 and χb1. However,the J/ψ production in the χb2 decay is dominated by the color-singlet process. Furthermore,the gluon fragmentation process gives a δ function in the energy fraction distribution of J/ψ,which can be considered to be another characteristic for its identification. From our estimation the branching ratio for these processes is about 10-4-10-5,which indicates that J/ψ inclusive production is detectable at B-factories. Studying these processes would help us to gain a deeper understanding of the color-octet mechanism.     

O(α_sv~2) correction to J/ψ plus η_c production in e~+e~- annihilation at s~(1/2)=10.6 GeV

Based on the nonrelativistic QCD factorization approach, O(αsv2) corrections to J/ψ plus ηc production in e+e-annihilation at √ s=10.6 GeV are calculated in this work. The numerical results show that the correction at αsv2order is only about a few percent of the total theoretical result. This indicates that the perturbative expansions become convergent and that a higher order correction will be smaller. The uncertainties from the long-distance matrix elements, renormalization scale and the measurement in the experiment are also discussed. Our result is in agreement with the previous result by Jia.