New LHCb pentaquarks as hadrocharmonium states
Abstract
New LHCb Collaboration results on pentaquarks with hidden charm [1] are discussed. These results fit nicely in the hadrocharmonium pentaquark scenario [2,3]. In the new data the old LHCb pentaquark splits into two states and . We interpret these two almost degenerate hadrocharmonium states with and as a result of hyperfine splitting between hadrocharmonium states predicted in [2]. It arises due to QCD multipole interaction between color-singlet hadrocharmonium constituents. We improve the theoretical estimate of hyperfine splitting [2,3] that is compatible with the experimental data. The new state finds a natural explanation as a bound state of and a nucleon, with , and binding energy 42 MeV. As a bound state of a spin-zero meson and a nucleon, hadrocharmonium pentaquark does not experience hyperfine splitting. We find a series of hadrocharmonium states in the vicinity of the wide pentaquark that can explain its apparently large decay width. We compare the hadrocharmonium and molecular pentaquark scenarios and discuss their relative advantages and drawbacks.
Keywords
Cite
@article{arxiv.1904.11616,
title = {New LHCb pentaquarks as hadrocharmonium states},
author = {Michael I. Eides and Victor Yu. Petrov and Maxim V. Polyakov},
journal= {arXiv preprint arXiv:1904.11616},
year = {2020}
}
Comments
10 pages