Study of isospin eigenstates of the pentaquark molecular states with strangeness

Abstract

In the present work, we construct eight color singlet-singlet type five-quark currents with strangeness to study the pentaquark states of DΞ ′ , DΞ * c , D * Ξ ′ c and D * Ξ * c via the QCD sum rules. The considered states are isospin eigenstates with isospin quantum number I = 1 or I = 0. Numerical results show that the central value of the masses extracted from the Borel platforms with high isospin are slightly above the thresholds of the meson and baryon constituents and the low isospin ones are a few dozens of MeV below, what's more, the present study supports the assignment of Pcs(4459) as DΞ * c molecular state with the IJ P = 0( 3 2 ) − . Technically, besides the analyses of the uncertainties of the masses and pole residues, detailed discussion about the contribution of vacuum condensates proportional to the mass of s quark are conducted which may present a reference for the technical application of QCD sum rules in the future work.

Analysis of the fully-heavy pentaquark states via the QCD sum rules

“…In the present work, we extend our previous works on the pentaquark molecular states to investigate the DΞ c , DΛ c , Ds Ξ c , Ds Λ c , D * Ξ c , D * Λ c , D * s Ξ c and D * s Λ c molecular states with distinguished isospins in the framework of the QCD sum rules [24,27,28,29]. We carry out the operator product expansion up to the vacuum condensates of dimension 13 consistently, just like what we did previously, and determine the best energy scales of the spectral densities using the modified energy-scale formula by considering the light-flavor SU (3) mass-breaking effects, and try to obtain the lowest color-singlet-color-singlet type pentaquark states as one of the color-neutral clusters has the same quantum numbers as the lowest charmed baryons in the flavor anti-triplet, and make possible assignments of the P cs (4338) and P cs (4459).…”