Resonance X(5568) as an exotic axial-vector state

Abstract

The mass and meson-current coupling constant of the resonance X(5568), as well as the width of the decay X(5568) → B * s π are calculated by modeling the exotic X(5568) resonance as a diquarkantidiquark state X b = [su][bd] with quantum numbers J P = 1 + . The calculations are made employing QCD two-point sum rule method, where the quark, gluon and mixed vacuum condensates up to dimension eight are taken into account. The sum rule approach on the light-cone in its softmeson approximation is used to explore the vertex X b B * s π and extract the strong coupling gX b B * s π , which is a necessary ingredient to find the width of the X b → B * s π + decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.

Studying the Bound State of the BK¯ System in the Bethe-Salpeter Formalism

“…In Refs. [10][11][12][13][14][15][16][17][18], the authors based on QCD sum rules obtained the mass and/or decay width which are in agreement with the experimental data. In Refs.…”

Masses of open charm and bottom tetraquark states in a relativized quark model

“…The experimental efforts have immediately attracted great interests and many theoretical studies on the X(5568) with different interpretations. Considering the mass, production, strong decay, and decay constant, many investigations regard the X(5568) as a tetraquark state within the framework of QCD sum rule and simple quark model [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], which explantation is suggested by D0 Collaboration. The structures under B s π, BK and B * K molecular pictures, dynamically generated states, and hybridized tetraquarks are also proposed [21][22][23][24][25][26][27][28][29][30].…”

“…Before the observation of X(5568), there existed a few studies on open charm and bottom tetraquark states, which mainly concentrated on the tetraquark interpretation of D * s0 (2317) [29][30][31][32][33][34][35]. The evidence of X(5568) immediately attracted great interests and many extensive theoretical investigations under various interpretations, such as tetraquark [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54], molecule [55][56][57][58][59][60][61][62][63][64], and kinematic effects [65][66][67]. Other related topics are also wildly discussed [68][69][70][71][72][73][74][75][76]…”

Open charm and bottom tetraquarks in an extended relativized quark model

“…Before the observation of Xð5568Þ, there existed a few studies on open charm and bottom tetraquark states, which mainly concentrated on the tetraquark interpretation of D Ã s0 ð2317Þ [29][30][31][32][33][34][35]. The evidence of Xð5568Þ immediately attracted great interest and many extensive theoretical investigations under various interpretations, such as a tetraquark [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55], molecules [56][57][58][59][60][61][62][63][64][65], and kinematic effects [66][67][68]. Other related topics were also widely discussed [69][70][71][72][73][74][75][76]…”