J/ψ mesons bound to nuclei

Full text: We discuss the experimental perspectives for the formation of a bound state of J/ψ to a nucleus. Since a J/ψ does not have quarks in common with the nuclear medium, its interactions with the medium necessarily involve the intervention of gluons - via the excitation of QCD van der Waals forces arising from the exchange of two or more gluons between color-singlet states [1], or the excitation of charmed hadronic intermediate states with light quarks created from the vacuum [2,3,4]. In the present communication we present results of explicit calculations [5] of energy levels for a range of nuclei using effective Lagrangians. Our results indicate that that J/ψ-nuclear bound states should produce a clear experimental signature provided that the J/ψ meson is produced in recoilless kinematics. [1] S.J. Brodsky, I.A. Schmidt, G.F. de Teramond, Phys. Rev. Lett. 64, 1011 (1990). [2] S.J. Brodsky, G.A. Miller, Phys. Lett. B 41, 125 (1997). [3] S.H. Lee, C.M. Ko, Phys. Rev. C 67, 038202 (2003). [4] G. Krein, A.W. Thomas, K. Tsushima, Phys. Lett. B 697, 136 (2011). [5] K. Tsushima, D.H. Lu, G. Krein, A. W. Thomas, Phys. Rev. C 83, 065208 (2011). (author)