The Overshadowed χ_c1(2p) Charmoniumlike Resonance

Unidad Teórica, Instituto de Física corpuscular (UV–CSIC), 46980 Paterna (Valencia), Spain

^* e-mail: roberto.bruschini@ific.uv.es

Published online: 22 December 2022

Abstract

A systematic analysis of J^PC = 1⁺⁺ charmoniumlike mesons with energies up to 4.0 GeV is carried out within the diabatic approach to QCD. The resulting spectrum contains only two bound states: the conventional 1p charmonium state and a D⁰ D̄^∗0 loosely bound state which may be naturally identified with X(3872). The rest of the spectrum consists in a continuum of D⁰ D̄^∗0 and D⁺D^∗− scattering states, whose analysis indicates the presence of a resonance near 3.96 GeV that may be assigned to a mostly conventional 2p charmonium state. It is shown that this χ_c1(2p) resonance is likely overshadowed in its expected main decay channels, D⁰ D̄^∗0 and D⁺D^∗−, by the threshold enhancements due to the loosely bound X(3872), which may justify its lack of detection to date. Alternative discovery channels are discussed.