We closely investigate NN potentials based upon the Delta-full version of chiral effective field theory. We find that recently constructed NN potentials of this kind, which (when applied together with three-nucleon forces) were presented as predictin
g accurate binding energies and radii for a range of nuclei from A=16 to A=132 and providing accurate equations of state for nuclear matter, yield a chi^2/datum of 60 for the reproduction of the pp data below 100 MeV laboratory energy. We compare this result with the first semi-quantitative $NN$ potential ever constructed in the history of mankind: the Hamada-Johnston potential of the year of 1962. It turns out that the chi^2 for the new Delta-full potentials is more than three times what was already achieved some 60 years ago. In fact, there has not been any known NN potential during the entire history of nuclear forces with a chi^2 as large as the ones of these recent Delta-full potentials of the Gothenburg-Oak Ridge group of the year of 2020. We perceive this historical fact as highly disturbing in view of the current trend for which the term precision has become the most frequently used label to characterize contemporary advances in microscopic nuclear structure physics. We are able to trace the very large chi^2 as well as the apparent success of the potentials in nuclear structure to unrealistic predictions for P-wave states, in which the Delta-full NNLO potentials are off by up to 40 times the NNLO truncation errors. In fact, we show that, the worse the description of the P-wave states, the better the predictions in nuclear structure. Misleading results of the above kind are unhelpful to the communitys efforts in microscopic nuclear structure, because they obscure a correct understanding of the nature of the remaining problems and, thus, hamper sincere attempts towards genuine solutions.
The two exotic $P_c^+(4380)$ and $P_c^+(4450)$ discovered in $2015$ by the LHCb Collaboration, together with the four resonances $X(4140)$, $X(4274)$, $X(4500)$ and $X(4700)$, reported in $2016$ by the same collaboration, are described in a constitue
nt quark model which has been able to explain the properties of charmonium states from the $J/psi$ to the $X(3872)$. Using this model we found a $bar DSigma_c^*$ bound state with $J^P=frac{3}{2}^-$ that may be identified with the $P_c^+(4380)$. In the $bar D^*Sigma_c$ channel we found three possible candidates for the $P_c^+(4450)$ with $J^P=frac{1}{2}^-$, $frac{3}{2}^-$ and $frac{3}{2}^+$ with almost degenerated energies. The $X(4140)$ resonance appears as a cusp in the $J/psiphi$ channel due to the near coincidence of the $D_{s}^{pm}D_{s}^{astpm}$ and $J/psiphi$ mass thresholds. The remaining three $X(4274)$, $X(4500)$ and $X(4700)$ resonances appear as conventional charmonium states with quantum numbers $3^{3}P_{1}$, $4^{3}P_{0}$ and $5^{3}P_{0}$, respectively; and whose masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds.
The recently discovered $P_c(4380)^+$ and $P_c(4450)^+$ states at LHCb have masses close to the $bar DSigma_c^*$ and $bar D^*Sigma_c$ thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze
these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The $P_c(4380)^+$ and $P_c(4450)^+$ are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the $bar DSigma_c^*$ and $bar D^*Sigma_c$ channels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the $bar DSigma_c$ and $bar D^* Sigma_c^*$ thresholds.
