New charged resonance $$Z_{c}^{-}(4100)$$ Z c - ( 4100 ) : the spectroscopic parameters and width

Abstract

The mass, coupling and width of the newly observed charged resonance Z − c (4100) are calculated by treating it as a scalar four-quark system with a diquarkantidiquark structure. The mass and coupling of the state Z − c (4100) are calculated using the QCD two-point sum rules. In these calculations we take into account contributions of the quark, gluon and mixed condensates up to dimension ten. The spectroscopic parameters of Z − c (4100) obtained by this way are employed to study its S-wave decays to η c (1S)π − , η c (2S)π − , D 0 D − , and J/ψρ − final states. To this end, we evaluate the strong coupling constants corresponding to the vertices Z c η c (1S)π − , Z c η c (2S)π − , Z c D 0 D − , and Z c J/ψρ − respectively. The couplings g Z c η c1 π , g Z c η c2 π , and g Z c D D are computed by means of the QCD three-point sum rule method, whereas g Z c J/ψρ is obtained from the QCD light-cone sum rule approach and soft-meson approximation. Our results for the mass m = (4080 ± 150) MeV and total width = (147 ± 19) MeV of the resonance Z − c (4100) are in excellent agreement with the existing LHCb data.

Newly observed exotic doubly charmed meson $T^{+}_{cc}$

“…Investigations demonstrate that these effects rescale the original coupling f and leave stable the mass m of the tetraquark [25,33]. Detailed analyses proved that two-meson contributions are small even for tetraquarks with width around a hundred MeV [25,33]. In the case under discussion, the width of the T + cc is less than one MeV, therefore two-meson effects can be safely neglected.…”

“…In the case of the tetraquarks they lead to modification in the quark propagator [32] 1 where Γ(p) is the finite width of the tetraquark generated by two-meson states. Investigations demonstrate that these effects rescale the original coupling f and leave stable the mass m of the tetraquark [25,33]. Detailed analyses proved that two-meson contributions are small even for tetraquarks with width around a hundred MeV [25,33].…”

Four-quark exotic mesons

“…[cu] diquark-antidiquark were computed in our paper [104]. There, we also explored decays of Z c and found its full width.…”

“…But hidden-charm η ′ c π − , J/ψρ − and open-charm D 0 D − and D * 0 D * − decays are also kinematically allowed S -wave channels of the resonance Z c . Below, we give detailed information about investigations of Z c based on our work [104].…”

Electromagnetic properties of doubly-heavy pentaquark states

“…Detailed investigations show that two-hadron scattering effects are small for multiquark hadrons (see Refs. [62][63][64][65][66][67][68][69][70][71][72]). Therefore, in the present study the zero-width single-pole approximation have been used.…”