Delicate interplay between the [D.sup.0][D.sup.0], [ρ.sup.0] J/ψ, and ωJ/ψ channels in the X resonance

• Published in: The European physical journal. C, Particles and fields Vol. 71; no. 10
• Main Authors: Coito, Susana, Rupp, George, van Beveren, Eef
• Format: Journal Article
• Language: English
• Published: Springer 01.10.2011
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-011-1762-7

The nature of the X(3872) enhancement is analyzed in the framework of the Resonance-Spectrum Expansion, by studying it as a regular [J.sup.PC] = [1.sup.++] charmonium state, though strongly influenced and shifted by opencharm decay channels. The observed but Okubo-Zweig-Iizuka-forbidden [ρ.sup.0] J/ψ and ω J/ψ channels are coupled as well, but effectively smeared out by using complex [ρ.sup.0] and ω masses, in order to account for their physical widths, followed by a rigorous algebraic procedure to restore unitarity. A very delicate interplay between the [D.sup.0] [D.sup.*0], [ρ.sup.0] J/ψ, and ω J/ψ channels is observed. The data clearly suggest that the X(3872) is a very narrow axial-vector c[bar.c] resonance, with a pole at or slightly below the [D.sup.0] [D.sup.*0] threshold.