Charmonium spectrum and electromagnetic transitions with higher multipole contributions

Abstract

The charmonium spectrum is calculated with two nonrelativistic quark models, the linear potential model and the screened potential model. Using the obtained wavefunctions, we evaluate the electromagnetic transitions of charmonium states up to 4S multiplet. The higher multipole contributions are included by a multipole expansion of the electromagnetic interactions. Our results are in reasonable agreement with the measurements. As conventional charmonium states, the radiative decay properties of the newly observed charmonium-like states, such as X(3823), X(3872), X(4140/4274), are discussed. The X(3823) as ψ 2 (1D), its radiative decay properties well agree with the observations. From the radiative decay properties of X(3872), one can not exclude it as a χ c1 (2P) dominant state. We also give discussions of possibly observing the missing charmonium states in radiative transitions, which might provide some useful references to look for them in forthcoming experiments. The higher multipole contributions to the electromagnetic transitions are analyzed as well. It is found that the higher contribution from the magnetic part could give notable corrections to some E1 dominant processes by interfering with the E1 amplitudes. Our predictions for the normalized magnetic quadrupole amplitudes M 2 of the χ c1,2 (1P) → J/ψγ processes are in good agreement with the recent CLEO measurements.

Triply charmed and bottom baryons in a constituent quark model

“…Recently, with this model we have studied the spectra of the charmonium, bottomonium, B c meson, Ω baryon, and fully-heavy tetraquark states. For there are no measurements of the triply heavy baryons which can be used to constrain the parameters potential model, the model parameters of this work are adopted with the determinations by fitting the charmonium and bottomonium spectra in our previous works [49][50][51]. The masses of the Ω ccc and Ω bbb baryon states predicted in present work reasonably agree with the results obtained with the Lattice QCD calculations [9,15].…”

“…In the above equations, the S i , S and L are the spin operator of the i-th quark, the total spin of the baryon and the total orbital angular momentum of the baryon, respectively; the parameter b, α i j , and α S O denote the strength of confinement potential, strong coupling, and spin-orbit potential, respectively. The seven parameters m c , m b , α cc , α bb , σ cc , σ bb , and b have been determined by fitting the charmonium and bottomonium spectra in our previous works [49][50][51]. In this work, we use the same value of parameter α S O as in Ref.…”

“…Consequently, the radiative decay processes of the excited Ω ccc or Ω bbb states may be crucial for establishing them if they are produced in experiments. In this work, radiative decays of the Ω ccc and Ω bbb states are calculated within a nonrelativistic constituent quark model developed in our previous study of the heavy quarkonia [49,52]. This model was also successfully extended to deal with the radiative decays of the B c meson states [53], Ω baryon states [54], singly baryon states [55][56][57], and doubly heavy baryon states [58,59].…”

Ω baryon spectrum and their decays in a constituent quark model

“…kinetic energy of the baryon system; r i j ≡ |r i − r j | is the distance between the i-th quark and j-th quark; zero point energy C 0 is a constant, and V i j (r i j ) stands for the effective potential between the i-th and j-th quark. In this work, we adopt a widely used potential form for V i j (r i j ) [26][27][28][29][30][31][32][33][34][35], i.e.…”

Excited bottom-charmed mesons in a nonrelativistic quark model

“…First, using the newly measured masses of B c (1S ) and B c (2S ) from the CMS Collaboration [5] and the 1S hyperfine splitting determined from the lattice QCD [36][37][38] as constrains, we calculate the B c mass spectrum up to the 6S multiplet with a nonrelativistic linear potential model. The slope parameter of the linear potential has been well determined in our previous study of the charmonium states [61]. To involve the spin-dependent corrections of the spatial wave functions, following the method adopted in Refs.…”