Weak decays of heavy hadrons into dynamically generated resonances

In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron…

The Ξ(1620) and Ξ(1690) molecular states from S = −2 meson-baryon interaction up to next-to-leading order

We have studied the meson-baryon interaction in the neutral $S=-2$ sector using an extended Unitarized Chiral Perturbation Theory, which takes into account not only the leading Weinberg-Tomozawa term (as all the previous studies in $S=-2$ sector), but also the Born terms and next-to-leading order contribution. Based on the SU(3) symmetry of the chiral Lagrangian we took most of the model parameters from the BCN model \cite{Feijoo:2018den}, where these were fitted to a large amount of experimental data in the neutral $S=-1$ sector. We have shown that our approach is able to generate dynamically both $\Xi(1620)$ and $\Xi(1690)$ states in very reasonable agreement with the data, and can natura…

D0D0π+ mass distribution in the production of the Tcc exotic state

Traces of the hidden-charm S=−1 pentaquark in the Λb→J/ΨηΛ decay

The hidden charm pentaquark state Pc (4450), observed recently by the LHCb collaboration in the Λb →J/ψK − p decay, may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness S=−1 sector. In this work we argue that a hidden-charm strange pentaquark could also be seen in the decay of theΛb , but through the J/ψη Λ decay mode, by studying the invariant mass spectrum of J/ψ Λ pairs.In our model we assume a standard weak decay topology, then incorporate the hadronization process and final state interaction effects, and we find that the J/ψη Λ final state is populated with the strength similar to that of the J/ψK− p . We have stud…

Shedding light on the $ X(3930) $ and $ X(3960) $ states with the $B^- \to K^- J/\psi \omega $ reaction

We have studied the contribution of the state $X(3930)$, coming from the interaction of the $D \overline{D}$ and $D^{+}_s D^{-}_s$ channels, to the $B^- \to K^- J/\psi \omega $ decay. The purpose of this work is to offer a complementary tool to see if the $X(3930)$ state observed in the $D^+ D^-$ channel is the same or not as the $X(3960)$ resonance claimed by the LHCb collaboration from a peak in the $D^{+}_s D^{-}_s$ mass distribution around threshold. We present results for what we expect in the $J/\psi \omega $ mass distribution in the $B^- \to K^- J/\psi \omega $ decay and conclude that a clear signal should be seen around $3930\,\rm MeV$. At the same time, finding no extra resonance s…

Femtoscopic correlation function for the $T_{cc}(3875)^+$ state

We have conducted a study of the femtoscopic correlation functions for the $D^0D^{*+}$ and $D^+D^{*0}$ channels that build the $T_{cc}$ state. We develop a formalism that allows us to factorize the scattering amplitudes outside the integrals in the formulas, and the integrals involve the range of the strong interaction explicitly. For a source of size of 1 fm, we find values for the correlation functions of the $D^0 D^{*+}$ and $D^+D^{*0}$ channels at the origin around 30 and 2.5, respectively, and we see these observables converging to unity already for relative momenta of the order of 200 MeV. We conduct tests to see the relevance of the different contributions to the correlation function…

Molecular Ωcc , Ωbb , and Ωbc states

Λb→J/ψKΞdecay and the higher order chiral terms of the meson baryon interaction

We study the weak decay of the ${\mathrm{\ensuremath{\Lambda}}}_{b}$ into $J/\ensuremath{\psi}K\mathrm{\ensuremath{\Xi}}$ and $J/\ensuremath{\psi}\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ states, and relate these processes to the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}J/\ensuremath{\psi}\overline{K}N$ decay mode. The elementary weak transition at the quark level proceeds via the creation of a $J/\ensuremath{\psi}$ meson and an excited $sud$ system with $I=0$, which upon hadronization leads to $\overline{K}N$ or $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ pairs. These states undergo final-state interaction in coupled channels and produce a final meson-baryon p…

X(3960) seen in Ds+Ds− as the X(3930) state seen in D+D−