Direct, Resonant Production of States with Positive Charge Conjugation in Electron-Positron Annihilation

¹ Institute of Physics, University of Silesia, PL-40007 Katowice, Poland
² Institutfür Theoretische Teilchenphysik, KarlsruheInstitute of Technology , D-76128 Karlsruhe, Germany

^* Work supported in part by the Polish National Science Centre, grant number DEC-2012/07/B/ST2/03867 and German Research Foundation DFG under Contract No. Collaborative Research Center CRC-1044.

Published online: 18 October 2019

Abstract

Recent theory results on direct production of resonances with positive charge conjugationin electron-positron annihilation are reviewed. The strong modeldependence is emphasized, with predictions varying between 0.03 eV and 0.43 eV for the charmonium state with J^PC = 1⁺⁺ and between0.16 eV and4.25 eV for the state with J^PC =2⁺⁺. For the state with J^PC = 0⁺⁺ the cross section is of O $\left({{\displaystyle m}}_e^2/{{\displaystyle M}}_x^2\right)$ and thus negligeable for all practical purpose. The importance of the relative phase of the production amplitude is emphasized.