Masses of tetraquarks with two heavy quarks in the relativistic quark model

Abstract

Masses of tetraquarks with two heavy quarks and open charm and bottom are calculated in the framework of the diquark-antidiquark picture in the relativistic quark model. All model parameters were regarded as fixed by previous considerations of various properties of mesons and baryons. The light quarks and diquarks are treated completely relativistically. The c quark is assumed to be heavy enough to make the diquark configurations dominating. The diquarks are considered not to be pointlike but to have an internal structure which is taken into account by the calculated diquark form factor entering the diquark-gluon interaction. It is found that all the (cc)(qq ′ ) tetraquarks have masses above the thresholds for decays into open charm mesons. Only the I(J P ) = 0(1 + ) state of (bb)(ūd) lies below the BB * threshold and is predicted to be narrow.

Exotic open-flavorbcq¯q¯,bChen1, Steele2, Zhu3 2014Phys. Rev. D92101030View full textAdd to dashboardCite

“…In the heavy quark sector, qQqQ-type hidden-flavor tetraquarks have been extensively studied to explain the underlying structures of the recently observed XY Z states in the relativistic quark model [8,9], QCD sum rules [10][11][12][13][14] and via bound diquark clusters [15][16][17][18]. The existence and stability of doubly charmed/bottomed QQqq tetraquark states have been also studied in the MIT bag model [19], chiral quark model [20,21], constituent quark model [22][23][24][25][26], relativistic quark model [27], chiral perturbation theory [28], QCD sum rules [29][30][31][32] and some other methods [33][34][35][36][37][38][39][40].…”

Exotic tetraquark states with the $$qq\bar{Q}\bar{Q}$$ q q Q ¯ Q ¯ configuration

“…One may consult Table V of Ref. [32] for more comparison. According to these two tables, most masses are below the upper limits of the present estimation (Scheme I) and are in the reasonable range.…”

“…1, there is also other work as regards qqQQ tetraquark states. Various approaches such as the non-relativistic quark model [24,25], the relativistic quark model [32], and the QCD sum rule [41] have been used to explore the spectra. For comparison, we briefly list the obtained results in the present model and those in other theoretical methods in Table 9.…”

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

“…Up to now, no experimental candidates for the doubly charmed tetraquark states ccqq or qq cc have been observed. There have been several works on the doubly heavy tetraquark states, such as potential quark models [17][18][19][20][21][22][23], QCD sum rules [24][25][26], heavy quark symmetry [27][28][29], lattice QCD [30][31][32], etc.…”