https://doi.org/10.1140/epjc/s10052-021-09229-y
Regular Article - Theoretical Physics
Tetraquark state X(6900) and the interaction between diquark and antidiquark
1
School of Science, Tianjin University, 300072, Tianjin, China
2
Cold Spring Harbor Laboratory, 11724, Cold Spring Harbor, NY, USA
Received:
6
April
2021
Accepted:
10
May
2021
Published online:
17
May
2021
Recently LHCb declared a new structure X(6900) in the final state di-
which is popularly regarded as a cc-
tetraquark state. Within the Bethe–Salpeter (B–S) framework we study the possible cc- bound states and the interaction between diquark (cc) and antidiquark (). In this work cc () is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of cc- bound state are 
, 
and 
. Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for the diquark and antidiquark system. Then we deduce the B–S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of X(6900) when we assign appropriate values for parameter 
introduced in the interaction (kernel). We also briefly calculate the spectra of bb-
bound states. Future measurement of bb- state will help us to determine the exact form of effective interaction.
© The Author(s) 2021
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3
