Charmonium molecules?
In this talk we present some recent studies of multiquark components in the charmonium sector. We study the possible existence of compact four quark-states and meson-meson molecules in the charmonium spectroscopy.
hep-ph↗
arXiv subjects
T. Fernandez-Carames
Publications and source records attributed to T. Fernandez-Carames.
Charmonium spectroscopy above thresholds
We present a systematic and selfconsistent analysis of four-quark charmonium states and applied it to study compact four-quark systems and meson-meson molecules. Our results are robust and should serve to clarify the situation of charmonium spectroscopy above the threshold production of charmed mesons.
hep-ph↗
$ΛNN$ and $ΣNN$ systems at threshold: II. The effect of D waves
Using the two-body interactions obtained from a chiral constituent quark model we study all $ΛNN$ and $ΣNN$ states with I=0,1,2 and J=1/2,3/2 at threshold, taking into account all three-body configurations with S and D wave components. We constrain further the limits for the $ΛN$ spin-triplet scattering length a_{1/2,1}. Using the hypertriton binding energy we find a narrow interval for the possible values of the $ΛN$ spin-singlet scattering length a_{1/2,0}. We found that the $ΣNN$ system has a quasibound state in the (I,J) = (1,1/2) channel very near threshold with a width of about 2.1 MeV.
hep-ph↗
$ΛNN$ and $ΣNN$ systems at threshold
We calculate the hypertriton binding energy and the $Λd$ and $Σd$ scattering lengths using baryon-baryon interactions obtained from a chiral constituent quark model. We study consistently the $ΛNN$ and $ΣNN$ systems analyzing the effect of the $Σ\leftrightarrow Λ$ conversion. Our interactions correctly predict the hypertriton binding energy. The $(I,J)=(0,3/2)$ $ΛNN$ channel is also attractive and it might have a bound state. From the condition of nonexistence of a (0,3/2) $ΛNN$ bound state, an upper limit for the spin-triplet $ΛN$ scattering length is obtained. We also present results for the elastic and inelastic $ΣN$ and $ΛN$ cross sections. The consistent description of the $ΣN$ scattering cross sections imposes a lower limit for the corresponding spin-triplet scattering lengths. In the $ΣNN$ system the only attractive channels are $(I,J)=(1,1/2)$ and $(0,1/2)$, the $(1,1/2)$ state being the most attractive one.
hep-ph↗
Strange tribaryons
We use two-body potentials derived from a constituent quark cluster model to analyze the bound-state problem of the $ΣNN$ system. The observables of the two-body subsystems, $NN$ and $ΣN$, are well reproduced. We do not find $ΣNN$ bound states, but there are two attractive channels with a resonance close above the three-body threshold. These channels are the $(I,J)=(1,1/2)$ and $(0,1/2)$, their quantum numbers, widths and energy ordering consistent with the recently measured strange tribaryons from the $^{4}{\rm He}(K_{\rm stopped}^{-},N)$ reactions in the KEK PS E471 experiment.
hep-ph↗
Diquark-diquark correlations in the $^1S_0$ $ΛΛ$ potential
We derive a $ΛΛ$ potential from a chiral constituent quark model that has been successful in describing one, two and three nonstrange baryon systems. The resulting interaction at low energy is attractive at all distances due to the $σ$ exchange term. The attraction allows for a slightly bound state just below the $ΛΛ$ threshold. No short-range repulsive core is found. We extract the diquark-diquark contribution that turns out to be the most attractive and probable at small distances. At large distances the asymptotic behavior of the $ΛΛ$ interaction provides a prediction for the $σΛΛ$ coupling constant.
hep-ph↗