Properties of heavy quarkonia andBcmesons in the relativistic quark model

Abstract

The mass spectra and electromagnetic decay rates of charmonium, bottomonium and B c mesons are comprehensively investigated in the relativistic quark model. The presence of only heavy quarks allows the expansion in powers of their velocities. All relativistic corrections of order v 2 /c 2 , including retardation effects and one-loop radiative corrections, are systematically taken into account in the computations of the mass spectra. The obtained wave functions are used for the calculation of radiative magnetic dipole (M1) and electric dipole (E1) transitions. It is found that relativistic effects play a substantial role. Their account and the proper choice of the Lorentz structure of the quark-antiquark interaction in a meson is crucial for bringing theoretical predictions in accord with experimental data. A detailed comparison of the calculated decay rates and branching fractions with available experimental data for radiative decays of charmonium and bottomonium is presented. The possibilities to observe the currently missing spin-singlet S and P states as well as D states in bottomonium are discussed. The results for B c masses and decays are compared with other quark model predictions.

The hidden-charm pentaquark and tetraquark states

“…The upper limit of B(X(3823) → χ c2 γ)/B(X(3823) → χ c1 γ) was measured to be < 0.41 by Belle [112], and < 0.42 by BESIII [118], consistent with the theoretical calculation for the 1 3 D 2 state in Refs. [844,116,845,846]. In addition, the partial decay width for ψ(1 3 D 2 ) → J/ψπ + π − obtained in these works was also in agreement with the observation by E705 [111].…”

“…They suggested this new resonance X(3823) as the 1 3 D 2 charmonium state with J PC = 2 −− . The mass and radiative decay behavior agree with the theoretical predictions for the 1 3 D 2 state [113,114,115,17,116,117]. Recently, the BESIII Collaboration confirmed the X(3823) resonance in the process of e + e − → π + π − X(3823) → π + π − γχ c1 at 6.2σ, with a mass (3821.7 ± 1.3 ± 0.7) MeV and width less than 16 MeV at the 90% C.L.…”

“…2.1.1.7, the X(3823) agrees with the theoretical predictions for the 1 3 D 2 state [113,114,115,17,116,117]. The 1 3 D 2 charmonium state with J PC = 2 −− is expected to be very narrow.…”

Hadronic loop contributions to J/ψ and ψ′ radiative decays into γLi1, Zhao2 2008Physics Letters B430161View full textAdd to dashboardCite

“…Relativistic quark model calculations show that a proper choice of the Lorentz structure of the quark-antiquark interaction in a meson is crucial for explaining the J/ψ → γη c data [27]. Systematic investigation of the M1 transitions in the framework of nonrelativistic effective field of QCD has been reported in Ref.…”

“…Theoretical studies of the heavy quarkonium M1 transitions with relativistic corrections are various in the literature [24,25,26,27,28,29,30,31]. Relativistic quark model calculations show that a proper choice of the Lorentz structure of the quark-antiquark interaction in a meson is crucial for explaining the J/ψ → γη c data [27].…”