Vector and scalar charmonium resonances with lattice QCD

• Published in: The journal of high energy physics 2015-09, Vol.2015 (9), p.1-24, Article 89
• Main Authors: Lang, C. B., Leskovec, Luka, Mohler, Daniel, Prelovsek, Sasa
• Format: Article
• Language: English
• Subjects: charmonium; Classical and Quantum Gravitation; decay width; Elementary Particles; Excitation; heavy quark physics; High energy physics; lattice QCD; Lattices; Mathematical analysis; Phase shift; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quantum chromodynamics; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Scalars; Scattering; Simulation; String Theory
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP09(2015)089

A bstract We perform an exploratory lattice QCD simulation of D D ¯ scattering, aimed at determining the masses as well as the decay widths of charmonium resonances above open charm threshold. Neglecting coupling to other channels, the resulting phase shift for D D ¯ scattering in p -wave yields the well-known vector resonance ψ (3770). For m π = 156 MeV, the extracted resonance mass and the decay width agree with experiment within large statistical uncertainty. The scalar charmonium resonances present a puzzle, since only the ground state χ c 0 (1 P ) is well understood, while there is no commonly accepted candidate for its first excitation. We simulate D D ¯ scattering in s -wave in order to shed light on this puzzle. The resulting phase shift supports the existence of a yet-unobserved narrow resonance with a mass slightly below 4 GeV. A scenario with this narrow resonance and a pole at χ c 0 (1 P ) agrees with the energy-dependence of our phase shift. Further lattice QCD simulations and experimental efforts are needed to resolve the puzzle of the excited scalar charmonia.