Possible ΛcΛ¯c molecular states and their productions in nucleon-antinucleon collision

Abstract

In this work, a study of possible molecular states from the ΛcΛ¯c interaction and their productions in nucleon-antinucleon collision is performed in a quasipotential Bethe-Salpeter equation approach. Two bound states with quantum numbers JPC=0−+ and 1−− are produced with almost the same binding energy from the ΛcΛ¯c interaction which is described by the light meson exchanges. However, the result does not support the assignment of experimentally observed Y(4630) as a ΛcΛ¯c molecular state because it is hard to obtain a peak near experimental mass of the Y(4630) which is far above the ΛcΛ¯c threshold. The possibility to search these states in nucleon-antinucleon collision is studied by including couplings to NN¯ and D(⁎)D¯(⁎) channels. The peaks can be found obviously near the ΛcΛ¯c threshold in the D⁎D¯⁎ channel at an order of amplitude of 10 μb. Too small width of state with 0−+ may lead to the difficulty to be observed in experiment. Based on the results in the current work, search for the ΛcΛ¯c molecular state with 1−− is suggested in process NN¯→D⁎D¯⁎, which is accessible at P¯ANDA.

Keywords

• Molecular state
• P¯ANDA
• ΛcΛ¯c interaction
• Nucleon-antinucleon collision
• Quasipotential Bethe-Saltpeter equation