Analysis of the Possible DD¯s0*(2317) and D*D¯s1*(2460) Molecules with QCD Sum Rules*

Abstract

In this article, we assume that there exist the pseudoscalar D D ¯ s 0 * ( 2317 ) and D * D ¯ s 1 * ( 2460 ) molecular states Z1,2 and construct the color singlet-singlet molecule-type interpolating currents to study their masses with the QCD sum rules. In calculations, we consider the contributions of the vacuum condensates up to dimension-10 and use the formula μ = M X / Y / Z 2 − ( 2 M c ) 2 to determine the energy scales of the QCD spectral densities. The numerical results, M Z 1 = 4.61 − 0.08 + 0.11 GeV and M Z 2 = 4.60 − 0.06 + 0.07 GeV , which lie above the D D ¯ s 0 * ( 2317 ) and D * D ¯ s 1 * ( 2460 ) thresholds respectively, indicate that the D D ¯ s 0 * ( 2317 ) and D * D ¯ s 1 * ( 2460 ) are difficult to form bound state molecular states, the Z1,2 are probably resonance states.

Excited $K$ meson, $K_c(4180)$, with hidden charm as a $D\bar{D}K$ bound state

“…Different from the DDK bound state, these two exotic states are more likely to be discovered at the current facilities because of their hidden charm nature. It is interesting to note that a recent study in QCD sum rules does not find a DD * s0 (2317) bound state [55], consistent with the current picture that the K c (4180) state is a three-body molecule. As a result, we strongly encourage our experimental colleagues to search for it.…”

Study of $Λ_c$$Λ_c$ dibaryon and $Λ_c$$\barΛ_c$ baryonium states via QCD sum rules

“…The QCD sum rules is a successful method in studying the hadronic properties [13][14][15][16][17][18][19][20][21][22][23][24][25]. It could be used to calculate the masses of hadrons, decay constants, hadronic form-factors, coupling constants, etc [26,27].…”

“…It could be used to calculate the masses of hadrons, decay constants, hadronic form-factors, coupling constants, etc [26,27]. This method has been applied extensively to study the hidden-charm (bottom) tetraquark (molecular) states [13][14][15][16][17][18][19][20][21][22][23][28][29][30] and pentaquark (molecular) states [31,32]. In this paper, we construct four six-quark local interpolating currents to study both the Λ c Λ c dibaryon and Λ c Λc baryonium states with the J P = 0 + , 0 − , 1 + and 1 − , respectively.…”

Analysis of the hidden-charm tetraquark mass spectrum with the QCD sum rules

“…As we choose the local current operators, it is better to refer the corresponding tetraquark states as the3 c 3 c -type, 6 c6c -type, 1 c 1 c -type and 8 c 8 c -type tetraquark states, respectively. In carrying out the operator product expansion, we usually truncate the vacuum condensates up to dimension 6 [4,5,24,25,26], 8 [3,6,7,8,9,10,27,28,29,30,31,39], or 10 [11,12,13,14,15,16,17,18,19,20,21,22,23,32,33,34,35,36,37,40]. Although the convergence of the operator product expansion requires that the contributions of the vacuum condensates of dimension 10, which are of the highest dimension, play a tiny important role in the Borel windows, the highest vacuum condensates are companied with the factors 1 T 2 , 1 T 4 , 1 T 6 , or 1 T 8 , and play an important role in determining the Borel windows so as to extract the reliable tetraquark (molecule) masses, we should take them into account in a consistent way, where the T 2 is the Borel parameter.…”