Observation of Doublecc¯Production ine+e−Annihilation at

Abstract

We report the observation of prompt J/psi via double cc; production from the e+e- continuum. In this process one cc; pair fragments into a J/psi meson while the remaining pair either produces a charmonium state or fragments into open charm. Both cases have been experimentally observed. We find cross sections of sigma[e+e- -->J/psieta(c)(gamma)]xB(eta(c)-->>or=4 charged)=(0.033(+0.007)(-0.006)+/-0.009) pb and sigma(e+e- -->J/psiD(*+)X)=(0.53(+0.19)(-0.15)+/-0.14) pb and infer sigma(e+e- -->J/psicc;)/sigma(e+e- -->J/psiX)=0.59(+0.15)(-0.13)+/-0.12. These results are obtained from a 46.2 fb(-1) data sample collected near the Upsilon(4S) resonance, with the Belle detector at the KEKB collider.

The leading twist light-cone distribution amplitudes for the S-wave and P-wave quarkonia and their applications in single quarkonium exclusive productions

“…Especially, the attempts in [23,24] open a way to connect the predictions of hard quarkonium exclusive productions within the collinear factorization directly to those made within the NRQCD factorization (for examples, the many theoretical calculations based on NRQCD factorizations [25][26][27][28][29][30][31][32][33][34][35][36][37][38], triggered by the recent experimental measurements of charmonium exclusive productions at B-factories [39][40][41]). In particular, in [42,43], the authors have shown that the collinear factorization indeed can reproduce the exact asymptotic behavior of NRQCD predictions at the leading logarithms (LL) and next-toleading order (NLO) of the strong coupling α s , respectively, for a certain class of the quarkonium exclusive productions, if one employs the leading twist LCDAs calculated in [24]; and the ERBL equations can be used to resum the large logarithms appearing the NRQCD factorization calculations for the exclusive quarkonium productions, while such resummation cannot be done within the NRQCD factorization.…”

“…We start with the heavy quark and anti-quark pair with the momenta 39) where the residual momenta q andq in the rest frame of heavy quark pair scale like q 0 =q 0 ∼ mv 2 , q = − q and | q| = | q| ∼ mv, where v ≪ 1. The total momentum of heavy quark pair…”

Recent results from BESIII

“…MeV/c 2 and Γ = 32.0±1.2(stat. )± with η c (2S) → K 0 S K ± π ∓ [34] and later on confirmed in the two-photon production of K 0 S K ± π m p [35,36] and in the double-charmonium production process e + e − → J/ψcc [37,38]. A controversial observation of the η c (2S) was made in the past with the crystal ball setup.…”

Hadronic production of heavy quarkonia at LHC

“…The possible reason is that the very use of potential model predictions and χ c2 decay width for charmonium production at high energies is rather questionable. From double charmonia production in exclusive electron-positron annihilation [25,26,27] we know, that with the increase of the interaction energy the width of the momentum distributions of heavy quarks in quarkonia also increases. In coordinate space it corresponds to the increase of the charmonium wave function and its derivative at the origin.…”