Can X(5568) be a tetraquark state?

Abstract

Very recently, the D0 collaboration has reported the observation of a narrow structure, X(5568), in the decay process X(5568) → B 0 s π ± using the 10.4fb −1 data of pp collision at √ s = 1.96 TeV. This structure is of great interest since it is the first hadronic state with four different valence quark flavors, b, s, u, d. In this work, we investigate tetraquarks with four different quark flavors. Based on the diquark-antidiquark scheme, we study the spectroscopy of the tetraquarks with one heavy bottom/charm quark and three light quarks. We find that the lowest-lying S-wave state, a tetraquark with the flavor [su][bd] and the spin-parity J P = 0 + , is about 150 MeV higher than the X(5568). Further detailed experimental and theoretical studies of the spectrum, production and decays of tetraquark states with four different flavors in the future are severely needed towards a better understanding its nature and the classification of hadron exotic states.

Interpretation of the newly observed Ωc0 resonances

“…2 are described in detail in Refs. [17,18,[22][23][24][25]. In order to give more information of the coupling constants, we extract the coupling constants from the baryon mass relations [17] (κ cs )3 = 2K(c, {u, s}) − K(c, {u, d}), (16)…”

Tetraquark states with open flavors

“…(s), (9) in which the subscript i runs from A to D, and Applying the Borel transform to the quark-gluon side, we have…”

“…[8], the authors constructed a series of tetraquark currents to calculate the corresponding mass in the framework of QCD sum rules, and their results support the X(5568) as a tetraquark state with quantum numbers J P = 0 + or 1 + . Wang and Zhu [9] employed the effective Hamiltonian approach to calculate the mass of the tetraquark state. The molecular picture of X b was carried out in Ref.…”

$$B_s\pi $$ B s π – $$B\bar{K}$$ B K ¯ interactions in finite volume and X(5568)

“…In Ref. [20], the lowest-lying tetraquark s-wave state was found to be 150 MeV higher than X (5568). On the experimental side, neither the LHCb nor the CMS Collaboration found a signal corresponding to X (5568) [21,22].…”