English

Deciphering the recently discovered tetraquark candidates around 6.9 GeV

High Energy Physics - Phenomenology 2021-01-19 v3 High Energy Physics - Experiment High Energy Physics - Theory

Abstract

Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at around 7240 MeV, very near to the threshold of two doubly charmed Ξcc\Xi_{cc} baryons. We argue in this note that these exotic hadrons are genuine tetraquarks and not molecules of charmonia. It is conjectured that they are V-baryonium tetraquarks, namely, have an inner structure of a baryonic vertex with a cccc diquark attached to it, which is connected by a string to an anti-baryonic vertex with a cˉcˉ\bar c \bar c anti-diquark. We examine these states as the analogs of the states Ψ(4360)\Psi(4360) and Y(4630)Y(4630)/Ψ(4660)\Psi(4660) which are charmonium-like tetraquarks. One way to test these claims is by searching for a significant decay of the state at 7.2 GeV into ΞccΞcc\Xi_{cc}\overline\Xi_{cc}. Such a decay would be the analog of the decay of the state Y(4630)Y(4630) into to ΛcΛc\Lambda_c\overline\Lambda_c. We further argue that there should be trajectories of both orbital and radial excited states of the X(6900)X(6900). We predict their masses. It is possible that a few of these states have already been seen by LHCb.

Keywords

Cite

@article{arxiv.2008.01095,
  title  = {Deciphering the recently discovered tetraquark candidates around 6.9 GeV},
  author = {Jacob Sonnenschein and Dorin Weissman},
  journal= {arXiv preprint arXiv:2008.01095},
  year   = {2021}
}

Comments

v1: 22 pages, 4 figures v2: typos corrected, minor additions and references added. 22 pages, v3: references added. 22 pages