Z_{c,b}-like states from QCD Laplace sum rules at NLO

Abstract

We review our results on $Z_{c}$-like states[1] which we complete with the ones on $Z_{b}$-like states by using relativistic QCD Laplace Sum Rules (LSR) within stability criteria and including Factorized Next-to-Leading Order (FNLO) Perturbative (PT) corrections and Lowest Order (LO) QCD condensates up to $\langle G^3 \rangle$. We emphasize the importance of PT radiative corrections for heavy quark sum rules in order to justify the use of the running heavy quark mass in the analysis. Our estimates are compiled in Tables 3 and 4. From our results, the observed $Z_{cs}(3983)$ state are good candidate for being ${\mathcal T}_{cs}$ tetramole (superposition of nearly degenerated molecules and tetraquark states having the same quatum numbers $J^{PC}$ and with almost the same couplings to the currents). The $Z_{cs}$ bump around 4100 MeV can be interpreted as a combination of $D^{*}_{0}D_{s1}$ and $D^{*}_{s0}D_{1}$ molecules. The physical states $Z_{cs}(4000)$ and $Z_{cs}(4220)$ found by LHCb are too low to be considered as the first radial excitations of $Z_{cs}(3983)$. For the future $Z_{b}$, $Z_{bs}$ and $Z_{bss}$, we suggest to scan the region around $(10.3 \sim 10.9)$ GeV while the 1st radial excitations are about 2.4 GeV above the ground states.