$α_sv^2$ corrections to $η_c$ and $χ_{cJ}$ production recoiled with a photon at $e^+e^-$ colliders

We consider the production of the $η_c$ and $χ_{cJ}$ states recoiled with a photon up to $\mathcal{O}(α_s v^2)$ at BESIII and B-factories within the frame of NRQCD factorization. With the corrections, we revisit the numerical calculations to the cross sections for the $η_c(nS)$ and the $χ_{cJ}(mP)$ states. We argue that the search for $XYZ$ states with even charge conjugation such as $X(3872)$, $X(3940)$, $X(4160)$, and $X(4350)$ recoiled with a photon at BESIII may help clarify the nature of these states. For completeness, the production of charmonium with even charge conjugation recoiled with a photon at B factories is also discussed.

No reviews yet.

No comments yet.