Analysis of X (5568) as Scalar Tetraquark State in Diquark-Antidiquark Model with QCD Sum Rules

Abstract

In this article, we take the X(5568) as the diquark-antidiquark type tetraquark state with the spin-parity J P = 0 + , construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum condensates of dimension-10, and study the mass and pole residue in details with the QCD sum rules. We obtain the value MX = (5.57 ± 0.12) GeV, which is consistent with the experimental data. The present prediction favors assigning the X(5568) to be the scalar tetraquark state.

Analysis of the scalar, axialvector, vector, tensor doubly charmed tetraquark states with QCD sum rules

“…The updated values of the effective heavy quark masses are M c = 1.82 GeV and M b = 5.17 GeV [43,44]. It is not necessary for the effective charm quark mass M c in the doubly charmed tetraquark states to have the same value as the one in the hidden-charm tetraquark states.…”

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

“…It has been proposed to be either a tetraquark state [3][4][5][6][7][8][9][10][11][12][13][14], a triangular singularity [15], or a molecular state [16]. Although these theoretical studies favor the existence of a state that can be identified as the X (5568), some other studies have yielded negative conclusions.…”

X,YandZStates

“…In some of these studies it was not possible to explain the reported properties of the X(5568) neither as a molecule nor as a tetraquark state [74][75][76][77][78][79]. However, in many other calculations it was possible to explain the reported properties [80][81][82][83][84][85][86][87].…”