The Extraction of the Near-Threshold J/ψ-Meson Photoproduction Reaction from Experimental Electroproduction Data

Abstract

The use of a method developed in the CLAS collaboration (Jefferson Lab, USA) to extract events of quasi-real photoproduction on nuclei from experimental data of electroproduction, as applied to the reaction of near-threshold photoproduction of the J/ψ-meson is described in this paper. Experimental data of electroproduction on a liquid hydrogen target, which was obtained on CLAS12 experimental setup, were analyzed. The photoproduction of e⁺e^– pairs were studied from ep → p'e⁺e^–X reaction, where e⁺e^– lepton pair is formed during the decay of the vector meson or virtual photon, p' is the recoil proton. The method of selection of fully exclusive of the final state e⁺e^–p'(e') reaction is given, where the lepton pair, e⁺e^– is formed during the decay of the J/ψ-meson, and the kinematics of the scattered electron, e', is derived from the analysis of the missing momentum of the system.