Spectrum of the fully-heavy tetraquark state QQQ¯′Q¯

Abstract

In this work, we systematically calculate the mass spectra of the S-wave fully heavy tetraquark states bbbb, cccc, and bbcc in two nonrelativistic quark models. A tetraquark state may be an admixture of a 6c −6c state and a3c − 3c one, where 6c −6c(3c − 3c) denotes the color configuration with a 6c (3c) diquark and a6c (3c) antidiquark. For the tetraquark states bbbb and cccc with J P C = 0 ++ , the 6c −6c state is lower than the3c − 3c one in both the two quark models, while the order of the bbcc states depend on models. The 6c −6c and3c − 3c mixing effects are induced by the hyperfine interactions between the diquark and antidiquark, while the contributions from the one-gluon-exchange (OGE) Coulomb or the linear confinement potentials vanish for the QQQ Q system. With the couple-channel effects, we obtain the similar mass spectra. The numerical results show that the ground QQQ Q (Q = b, c and Q = b, c) tetraquark states are located above the corresponding scattering states, which indicates that there may not exist a bound state in the scheme of the two quark models.

Masses of fully heavy tetraquarks $$QQ {\bar{Q}} {\bar{Q}}$$ in an extended relativized quark model

“…For the bbbb system, the masses are also above the relevant ϒϒ thresholds. These results for the ground states are consistent with nonrelativistic quark model calculations where the pairwise potentials are adopted properly [32][33][34][35]44].…”

“…[15][16][17][18][19][20][21][22][23][24][25][26], the lowest bbbb tetraquark state is estimated to be below the threshold of bottomonium meson pair, while in Refs. [27][28][29][30][31][32][33][34][35], all the bbbb tetraquark states are above the threshold. To further distinguish different model and reveal the underlying dynamics of fully heavy tetraquark states, more efforts are needed, especially from the experimental side.…”

Light vector and axial mesons effective couplings to constituent quarks

“…Although it is possible to constraint the phenomenological couplings usually suitable for the hadron and nuclear dynamical models, it is highly desirable to obtain a QCD-based derivation of the mechanism according to which the vector-mesons -baryons interactions emerge. There are considerable difficulties to obtain the complete QCD effective action by integrating out gluons exactly from QCD [25]. However it is already interesting to understand the emergence of hadron interactions from a restricted part of the QCD effective action.…”

Nonrelativistic model of tetraquarks and predictions for their masses from fits to charmed and bottom meson data

“…Furthermore, we will compare the masses of diquarks and tetraquarks calculated in this model with those presented in Refs. [27,33,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. In Tables VI, VII, and VIII, we display the different comparisons.…”