Abstract
We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to the exclusive processes gamma +gamma rightarrow {mathcal {Q}}+{mathcal {Q}}, with {mathcal {Q}}=J/psi , eta _c, Upsilon , or eta _b, in the framework of non-relativistic QCD (NRQCD) factorization formalism. The cross sections at the SuperKEKB electron–positron collider, as well as at the future colliders, like the circular electron positron collider (CEPC) and the international linear collider (ILC), are evaluated. Numerical result indicates that the processes for J/psi -pair production and eta _c-pair production are hopefully observable at the Belle II detector within the next decade.
Highlights
The J/ψ meson is thought of an ideal laboratory to investigate the perturbative and non-perturbative properties of quantum chromodynamics (QCD) since its discovery in 1974
In Ref. [8], the leading order (LO) calculation of exclusive J/ψ-pair production via photon–photon fusion was performed within the non-relativistic QCD (NRQCD) factorization framework, while the J/ψ-pair diffractive production was investigated in the pomeron exchange scheme [9,10,11,12]
While for ηc-pair production, after including the next-to-leading order (NLO) corrections, the total cross sections are enhanced by a factor of about 2, and the theoretical uncertainty is reduced
Summary
The J/ψ meson is thought of an ideal laboratory to investigate the perturbative and non-perturbative properties of quantum chromodynamics (QCD) since its discovery in 1974. The non-relativistic QCD (NRQCD) factorization formalism [1], which proposed by Bodwin, Braaten, and Lepage, provide a systematic framework for the theoretical study of quarkonium physics. In the NRQCD factorization formalism, the quarkonium production and decay rates can be factorized as process dependent, but perturbative calculable, short distance coefficients and universal long distance matrix elements (LDMEs). The relative importance between the LDMEs can be estimated by means of velocity scaling rules. In this way, the theoretical prediction takes the form of a double expansion in the strong coupling constant αs and the heavy quark relative velocity v. 2, we present the primary formulae employed in the calculation. 3, we elucidate some technical details for the analytical calculation.
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