Exclusive processes of charmonium production and charmonium wave functions

Abstract

Results obtained by studying the properties of the leading-twist wave functions for the S-and P -wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes of charmonium production were performed within the models in question.

Associated Charmonium-Bottomonium Production in a Single Boson e+e− Annihilation

“…As shown in Figure 4 the EW contribution exceeds the QCD contribution starting with some energy both for the J/ψ η b -pair production and the Υ η c -pair production in total agreement with (20).…”

“…It is worth noting here the intrigue related to the observation of J/ψ η c pair in the e + e − annihilation: the theoretical predictions [1] underestimated the real yield measured at BELLE and BaBar [2,3] by the order of magnitude. This stimulated numerous studies [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], as a result of which a fair agreement with the data has been achieved. The previous year gave researchers a new sensation: the LHCb Collaboration observed the structure in the J/ψ J/ψ spectrum at large statistics [22].…”

“…Another problem that is outside the scope of this study is the relativistic effects caused by the use of relativistic or relativized wave functions. It is known that accounting for such effects can crucially change the predictions, especially for the charmonium-pair production in the e + e − annihilation, where accounting for the relativistic effects decreases the virtuality of the intermediate gluon, and therefore essentially increases the cross section value (see for example [9][10][11][12][13][14][15][16][17][18][19][20][21]). Another example of the influence of the relativistic effects on the paired quarkonium production could be found in [29][30][31][32].…”

New approach to the resummation of logarithms in Higgs-boson decays to a vector quarkonium plus a photon

“…These higher x moments are related to corrections to the LCDA of higher order in v 2 (see Refs. [16][17][18] and Appendix C) and to higher x moments of the corrections to the LCDA of order α s and higher. It is not clear that the functional form of the LCDA accounts adequately for these corrections.…”

“…In order α 0 s , the x moments of the LCDA [Eq. (C3)] have the following relationships to the NRQCD LDMEs [16][17][18]:…”