Phenomenological Study of J/ψ Photoproduction on Nucleon = 핵자에서의 J/ψ 광생성에 대한 현상론적 연구

다국어 초록 (Multilingual Abstract)

We present a unified description of J/ψ photoproduction on the nucleon from threshold to W = 300 GeV by combining a dynamical hadronic model with diffractive Pomeron exchange. The hadronic sector is built from a phenomenological charm–nucleon potential vcN(r), formulated in Yukawa form and folded with the J/ψ wave function ΦJ/ψ(cc̄) obtained in a constituent quark model (CQM), yielding an effective J/ψ–nucleon interaction VJ/ψN(r). The photoproduction amplitude is computed from a cc̄ loop that couples the γ→cc̄ vertex to ΦJ/ψ, without invoking vector–meson dominance. This approach is crucial for accurately describing the behavior near threshold. The parameters of vcN(r) are constrained such that the long–range part of VJ/ψN(r) reproduces the Yukawa tail seen in lattice QCD, and are fitted to Jefferson Lab (JLab) total and differential cross sections with explicit final–state interactions (FSI). The resulting dσ/dt agree well with GlueX and Hall C data, and the analysis indicates that FSI dominate in the near–threshold region, providing sensitivity to the J/ψ–N scattering amplitude. With the same CQM inputs, we also predict ηc(1S) and ψ(2S) photoproduction cross sections, offering benchmarks for future measurements at JLab and the EIC. We further extend the framework to include coupled–channel (rescattering) effects through intermediate D̄0Λ+c and D̄∗0Λ+c states, consistently incorporating s–, t–, and u– channel mechanisms. These open–charm channels generate cusp–like enhancements in the total cross section near their respective thresholds, W ≃ 4.2–4.3 GeV, and account for the observed structure in the data. At higher energies, Pomeron exchange governs the cross section, while near threshold the interplay of FSI and coupled–channel dynamics is essential for a quantitative description.

목차 (Table of Contents)

• 1 Introduction 1
• 2 Meson-Baryon Reaction 6
• 2.1 Lippmann–Schwinger Equation 7
• 2.2 Cross Section Observable 9
• 2.3 Matrix Element of the Potential 14
• 3 Pomeron Exchange Model 19
• 3.1 The Pomerons 19
• 3.2 Diffractive production of vector meson 23
• 3.3 Pomeron-exchange Amplitude 27
• 4 Dynamical Model 29
• 4.1 General Formalism 30
• 4.2 Final State Interaction 37
• 4.3 Result 39
• 4.3.1 1Y and 2Y comparison 40
• 4.3.2 LQCD constraints 43
• 4.3.3 Photo-production of ηc(1S) and ψ(2S) 50
• 5 Coupled Channel Model 53
• 5.1 General Formalism 54
• 5.1.1 D̄0Λ+c Intermediate State 57
• 5.1.2 D̄∗0Λ+c Intermediate State 60
• 5.2 Result 62
• 5.2.1 Comparison with data 63
• 5.2.2 Comparison with Dynamical Model 67
• 5.2.3 Open Charm Production 69
• 6 Conclusions 71
• Bibliography 73
• Appendices 78
• A Regge Phenomenology 79
• B Numerical Calculation Method 85
• C J/ψ→ e+e− Decay Width 89