Exclusive heavy-meson pair production at large recoil

Exclusive ${\rm{D\bar D}}$ meson pair production in peripheral ultrarelativistic heavy ion collisions

“…The resulting pseudoscalar-pseudoscalar (PP) production amplitude M γγ P P (λ, λ ′ ) can be written as [5] M γγ P P (λ, λ ′ ) = 2…”

“…3 we show the energy dependence of the elementary γγ → D + D − (D 0 D0 ) cross sections calculated according to the formalism used in Ref. [5] with the cut on meson transverse momenta. The cross section for D 0 D0 is larger than that for D + D − close to the threshold but falls faster with increasing W γγ .…”

“…FIG. 3: The energy dependence of the γγ → D + D − (black line) and γγ → D 0 D0 (dashed, red online) in the heavy-quark approximation [5]. In this calculations we have imposed an extra cut on the D-meson transverse momenta p t > 1 GeV.…”

“…Finally, the nuclear cross section can be expressed as the five-fold integral: N N = 5500 GeV) calculated with distribution amplitudes from [5] and [10].…”

“…Heavy quark meson pair production was studied theoretically only in Ref. [5] where formulas have been derived in the heavy quark approximation with Dirac delta-like distribution amplitudes. On the other hand both lattice QCD [6] and the CLEO collaboration [7] extracted the D-meson distribution amplitude which turned out to differ considerably from the delta-like distribution amplitude assumed in heavy quark approximation.…”