2009/03/31 by Bai-Qing Li, Kuang-Ta Chao · 1 citation
Physics and Astronomy · #hep-ex #hep-ph
paper · pdf · doi:10.1103/physrevd.79.094004
published as Phys.Rev.D79:094004,2009 · Total width of X(3872) reestimated, references added; 12 pages, 1 figure; published version in PRD
arxiv created 2009/05/07 · arxiv updated 2009/12/01
We incorporate the color-screening effect due to light quark pair creation into the heavy quark-antiquark potential, and investigate the effects of screened potential on the spectrum of higher charmonium. We calculate the masses, electromagnetic decays, and E1 transitions of charmonium states in the screened potential model, and propose possible assignments for the newly discovered charmonium or charmonium-like "X,Y,Z" states. We find the masses of higher charmonia with screened potential are considerably lower than those with unscreened potential. The χc2(2P) mass agrees well with that of the Z(3930), and the mass of ψ(4415) is compatible with ψ(5S) rather than ψ(4S). In particular, the discovered four Y states in the ISR process, i.e., Y(4008), Y(4260), Y(4320/4360), Y(4660) may be assigned as the ψ(3S), ψ(4S), ψ(3D), ψ(6S) states respectively. The X(3940) and X(4160) found in the double charmonium production in e+e- annihilation may be assigned as the ηc(3S) and χc0(3P) states. Based on the calculated E1 transition widths for χc1(2P)→ γJ/ψ and χc1(2P)→ γψ(2S) and other results, we argue that the X(3872) may be a χc1(2P) dominated charmonium state with some admixture of the D0D*0 component. Possible problems encountered in these assignments and comparisons with other interpretations for these X,Y,Z states are discussed in detail. We emphasize that more theoretical and experimental investigations are urgently needed to clarify these assignments and other interpretations.