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.

中文翻译：

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从实验电生产数据中提取近阈值J/ψ-介子光生产反应

摘要

使用 CLAS 合作（美国杰斐逊实验室）开发的方法从电产生的实验数据中提取核上准真实光产生的事件，应用于 J/ψ 介子的近阈值光产生反应是在本文中描述。分析了在 CLAS12 实验装置上获得的液氢靶电生产实验数据。从 ep → p'e ⁺ e ^– X 反应研究了 e ⁺ e ^–对的光产生，其中 e ⁺ e ^–轻子对是在矢量介子或虚光子衰变过程中形成的，p' 是反冲质子。完全排除最终状态 e ⁺的选择方法给出了 e ^– p'(e') 反应，其中轻子对 e ⁺ e ^–是在 J/ψ 介子衰变期间形成的，散射电子的运动学 e' 来自分析系统失去的动量。