$J/Ψ$ and $χ_{cJ}(J=0,1)$ production in electron-positron annihilation at $\sqrt{s}=10.6$ GeV in the framework of Bethe-Salpeter equation

Abstract

In present work we study the production of ground and excited charmonium pairs in e − e + → Ψ(nS) + χ cJ (nP ) for J = 0, 1 and n = 1, 2, through leading order (LO) tree-level diagrams ∼ O(α em α s ), which proceed through exchange of a virtual photon and an internal gluon line connecting two quark lines (in the triangle quark loop part of the diagram), in the framework of 4 × 4 Bethe-Salpeter equation, at center of mass energy, √ s = 10.6GeV. We have tried to show that the cross sections for this process calculated with use of the four leading order ∼ O(α em α s ) diagrams using BSE approach come close to experimental data, which might be mainly due to the consistent treatment of motion of quarks inside the hadrons in the BSE framework.