2024/09/16 by А. М. Бадалян, Badalian, A. M.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2409.10761
openalex publication_date 2024/09/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The masses, the fine-structure splitting, and two-photon decay widths of the higher nP-charmonium states are calculated in the relativistic string model, reduced to the spinless Salpeter equation, where the static potential has no fitting parameters and the c-quark mass has the physical value. The resulting masses of hc(3P), χc1(3P), χc0(4P), χc0(5P), χc1(5P) are obtained in a good agreement with the experimental masses of the LHCb resonances: hc(4300), χc1(4274), X(4500), X(4700), X(4685). To test sensitivity of results to a chosen gluon-exchange (GE) potential, three types of Vge(r) are considered. In first case the non-screened GE potential with large vector coupling at asymptotic, α\rm V(\rm asym.)=0.635, and the c-quark mass mc=1.430 GeV are taken; in second case a screened Vge and mc=1.385 are investigated, and in third case the GE potential is totally suppressed, Vge=0, and mc=1.32 GeV. The agreement with experiment is reached only if the same (universal) flattened confining potential, introduced in the analysis of the radial Regge trajectories of light mesons, is used. The unobserved 6P,0+ resonance with the mass ≅ 4.81 GeV, near J/ψϕ(1680) threshold, is predicted. Our analysis shows that the screening of the GE potential is possible but weakly affects the physical results obtained. The calculated two-photon decay widths weakly differ in the three cases but may become an important factor, which distinguishes c c and four-quark states.