Interpreting the X (5568)

Abstract

A variety of options for interpreting the DØ state, X(5568), are examined. We find that threshold, cusp, molecular, and tetraquark models are all unfavoured. Several experimental tests for unravelling the nature of the signal are suggested.

Four-quark structure of the Zc(3900) , Z(4430) , and Fabian1, Gutsche2, Ivanov3 et al. 2016Phys. Rev. D

“…Also the authors of Ref. [23] deduced a lower limit for the masses of a possible (bsud) tetraquark state: 6019 (6107) MeV. Complementary to Ref.…”

“…In Ref. [23] a few options for the interpretation of the X(5586) state have been checked. It was concluded that threshold, cusp, molecular, and tetraquark approaches for the explanation of the X(5586) state are all disfavored.…”

“…Complementary to Ref. [23] Ref. [24] presented an analysis based on general properties of QCD to analyze the X(5568) states.…”

Generating a resonance-like structure in the reaction $$B_c\rightarrow B_s \pi \pi $$ B c → B s π π

“…In fact, right after the observation by D0, the possible existence of this state was challenged on theoretical grounds; see Refs. [67][68][69]. The reason of its appearance in the D0 and absence in LHCb and CMS experiments is discussed in Ref.…”

Estimating decay rate of $$X^{{\pm }}(5568)\rightarrow B_s\pi ^{{\pm }}$$ X ± ( 5568 ) → B

“…The authors of Ref. [32] regard that neither a molecular state nor a tetraquark can explain the data, so they consider that B s π is produced in an electroweak decay where an extra hadron is also created, but evades detection.…”