R. Molina

University of Valencia | UV · Theoretical physics

We have studied the Ω c → π + ( π 0 , η ) π Ξ * and Ω c → π + ( π 0 , η ) K ¯ Σ * decays, where the final π Ξ * or K ¯ Σ * comes from the decay of two resonances around the nominal Ξ ( 1820 ) , which are generated from the interaction of coupled channels made of a pseudoscalar and a baryon of the decuplet. The π Ξ * mass distributions obtained in t...

We address a general problem in the evaluation of triangle loops stemming from the consideration of the range of the interaction involved in some of the vertices, as well as the energy dependence of the width of some unstable particles in the loop. We find sizeable corrections from both effects. We apply that to a loop relevant to the D s + → π + π...

The N * ( 1535 ) can be dynamically generated in the chiral unitary approach with the coupled channels, K 0 Σ + , K + Σ 0 , K + Λ , and η p . In this work, we evaluate the correlation functions for every channel and face the inverse problem. Assuming the correlation functions to correspond to real measurements, we conduct a fit to the data within a...

We investigate the dependence of both light and heavy quark masses on the properties of low-lying charmed mesons within the framework of one-loop HHX PT. Determination of the low energy constants is accomplished through an analysis of lattice data obtained from various Lattice Quantum Chro-modynamics (LQCD) simulations. Model selection tools are em...

We investigate the D*K* and Dsρ* interaction in coupled channels within the hidden gauge formalism. A structure is developed around their thresholds, short of producing a bound state, which leads to a peak in the Ds⁺π¯ mass distribution in the B⁰ → D¯⁰ Ds⁺π¯ decay compatible with the experimental data. We conclude that the interaction between the D...

DOI:https://doi.org/10.1103/PhysRevD.106.099905

In this work we investigate the possibility of the formation of states from the dynamics involved in the $D^*D^*D^*$ system by considering that two $D^*$'s generate a $J^P=1^+$ bound state, with isospin 0, which has been predicted in an earlier theoretical work. We solve the Faddeev equations for this system within the fixed center approximation an...

We have studied the exotic doubly charmed D*D system providing a natural explanation for the peak recently observed by LHCb, in terms of D*+D⁰ and D*0D⁺ with isospin I = 0. The width has been evaluated accurately based on the decay widths of the D* states. The D⁰D⁰π⁺ decay mode of the bound state formed is studied in detail, showing a narrow peak b...

We study for the first time the pΣ⁻ → K⁻d and its time reversal reaction close to threshold and show that they are driven by a triangle mechanism, with the Λ(1405), a proton and a neutron as intermediate states, which develops a triangle singularity close to the K̅d threshold. As the main result, we find that the cross section, well within measurab...

We have chosen the B¯0→D⁎+D¯⁎0K− reaction in order to observe the I=0,JP=1+ (R1) partner state of the X0(2866) stemming from the D⁎K¯⁎ molecular picture. The reaction proceeds via external emission in the most favored Cabibbo decay mode and one observes the R1 state as a very strong peak versus the background in the D⁎+K− spectrum. The branching ra...

We propose two reactions, B¯0→K0D+K− and B¯0→K*0D*+K−, which have been already measured at Belle, to look into the JP=0+, X0(2866) state and a 1+ partner of molecular D*K¯* nature by looking at the D+K− and D*+K− invariant mass distributions, respectively. Very clear peaks over the background are predicted and the branching ratios for the productio...

We study the interaction of the doubly bottom systems BB, B*B, BsB, Bs*B, B*B*, B*Bs, B*Bs*, BsBs, BsBs*, Bs*Bs* by means of vector meson exchange with Lagrangians from an extension of the local hidden gauge approach. The full s-wave scattering matrix is obtained implementing unitarity in coupled channels by means of the Bethe-Salpeter equation. We...

We propose two reactions, $\bar{B}^0 \to K^0 D^{+} K^-$ and $\bar{B}^0 \to K^{*0} D^{*+} K^-$, already measured at Belle, to look into the $J^P=0^+$, $X_0(2866)$ state and a $1^+$ partner of molecular $D^*\bar{K}^*$ nature, by looking at the $D^+ K^-$ and $D^{*+} K^-$ invariant mass distributions, respectively. Very clear peaks over the background...

We have chosen the $\bar{B}^0 \to D^{*+} \bar{D}^{*0} K^-$ reaction in order to observe the $I=0, J^P=1^+$ ($R_1$) partner state of the $X_0(2866)$ stemming from the $D^*\bar{K}^*$ molecular picture. The reaction proceeds via external emission in the most favored Cabibbo decay mode and one observes the $R_1$ state as a very strong peak versus the b...

We extend the theoretical framework used to describe the Tcc state as a molecular state of D∗D and make predictions for the D∗D∗ and Ds∗D∗ systems, finding that they lead to bound states only in the JP=1+ channel. Using input needed to describe the Tcc state, basically one parameter to regularize the loops of the Bethe-Salpeter equation, we find bo...

We study the interaction of the doubly bottom systems $BB$, $B^* B$, $B_s B$, $B_s^* B$, $B^* B^*$, $B^* B_s$, $B^*B_s^*$, $B_s B_s$, $B_s B_s^*$, $B_s^* B_s^*$ by means of vector meson exchange with Lagrangians from an extension of the local hidden gauge approach. The full s-wave scattering matrix is obtained implementing unitarity in coupled chan...

We study the Ds*D¯* system in connection with the J/ψK* in coupled channels and observe that, within reasonable values of the cutoff used to regularize the loops, the system does not develop a bound state. However, the JP=2+ channel has enough attraction to create a strong cusp structure that shows up in the J/ψK+ invariant mass distribution in the...

We study the $D^{*}_s \bar D^*$ system in connection with the $J/\psi K^*$ in coupled channels and observe that, within reasonable values of the cut-off used to regularize the loops, the system does not develop a bound state. However, the $J^P = 2^+$ channel has enough attraction to create a strong cusp structure that shows up in the $J/\psi K^+$ i...

We extend the theoretical framework used of describe the $T_{cc}$ state as a molecular state of $D^* D$ and make predictions for the $D^*D^*$ and $D^*_s D^*$ systems, finding that they lead to bound states only in the $J^P=1^+$ channel. Using input needed to describe the $T_{cc}$ state, basically one parameter to regularize the loops of the Bethe-S...

We develop a model for the pp→π+d reaction based on the pp→Δ(1232)N transition followed by Δ(1232)→πN′ decay and posterior fusion of NN′ to give the deuteron. We show that the triangle diagram depicting this process develops a triangle singularity leading to a large cross section of this reaction compared to ordinary fusion reactions. The results o...

We study for the first time the $p\Sigma^-\to K^-d$ and $K^-d\to p\Sigma^-$ reactions close to threshold and show that they are driven by a triangle mechanism, with the $\Lambda(1405)$, a proton and a neutron as intermediate states, which develops a triangle singularity close to the $\bar{K}d$ threshold. We find that a mechanism involving virtual p...

We develop a model for the $pp \to \pi^+ d$ reaction based on the $pp \to \Delta(1232) N$ transition followed by $\Delta(1232) \to \pi N'$ decay and posterior fusion of $N N'$ to give the deuteron. We show that the triangle diagram depicting this process develops a triangle singularity leading to a large cross section of this reaction compared to o...

We study the e+e−→K+(Ds⁎−D0+Ds−D⁎0) reaction recently measured at BESIII, from where a new Zcs state has been reported. We study the interaction of D¯sD⁎ with the coupled channels J/ψK−, K⁎−ηc, Ds−D⁎0, Ds⁎−D0 by means of an extension to the charm sector of the local hidden gauge approach. We find that the Ds−D⁎0+Ds⁎−D0 combination couples to J/ψK−...

We study the $e^+ e^- \to K^+ ( D_s^{*-} D^0 + D_s^- D^{*0})$ reaction recently measured at BESIII, from where a new $Z_{cs}$ state has been reported. We study the interaction of $\bar D_s D^*$ with the coupled channels $J/\psi K^-$, $K^{*-} \eta_c$, $D_s^- D^{*0}$, $D_s^{*-} D^0$ by means of an extension to the charm sector of the local hidden gau...

A bstract Recent lattice data on ππ -scattering phase shifts in the vector-isovector channel, pseudoscalar meson masses and decay constants for strange-quark masses smaller or equal to the physical value allow us to study the strangeness dependence of these observables for the first time. We perform a global analysis on two kind of lattice trajecto...

Based on the picture that the \( f_0(1370), f_0(1710), f_2(1270), f'_2(1525), {\bar{K}}^{*0}_2(1430)\) resonances are dynamically generated from the vector-vector interaction, we study the decays \(J/\psi \rightarrow \phi (\omega ) f_0(1370) [f_0(1710)]\), \(J/\psi \rightarrow \phi (\omega ) f_2(1270) [f'_2(1525)]\), and \(J/\psi \rightarrow K^{*0}...

Recent lattice data on $\pi\pi$-scattering phase shifts in the vector-isovector channel, pseudoscalar meson masses and decay constants for strange-quark masses smaller or equal to the physical value allow us to study the strangeness dependence of these observables for the first time. We perform a global analysis on two kind of lattice trajectories...

We evaluate the contribution to the X(3872) width from a triangle mechanism in which the X decays into \(D^{*0}{\bar{D}}^0 -cc\), then the \(D^{*0} ({\bar{D}}^{*0})\) decays into \(D^0 \pi ^0\) (\({\bar{D}}^0 \pi ^0\)) and the \(D^0 {\bar{D}}^0\) fuse to produce \(\pi ^+ \pi ^-\). This mechanism produces an asymmetric peak from a triangle singulari...

We evaluate the contribution to the $X(3872)$ width from a triangle mechanism in which the $X$ decays into $D^{*0}\bar{D}^0 -cc$, then the $D^{*0} (\bar{D}^{*0})$ decays into $D^0 \pi^0$ ($\bar{D}^0 \pi^0$) and the $D^0 \bar{D}^0$ fuse to produce $\pi^+ \pi^-$. This mechanism produces a triangle singularity visible at a precise value of the $\pi^+...

In a recent paper [1], the BESIII Collaboration reported the so-called first observation of pure W-annihilation decays Ds+→a0+(980)π0 and Ds+→a00(980)π+. The measured absolute branching fractions are, however, puzzlingly larger than those of other measured pure W-annihilation decays by at least one order of magnitude. In addition, the relative phas...

From an analysis of recent ($I=J=1$)-$\pi\pi$-phase-shift and pseudoscalar-meson decay-constant lattice data on two distinct chiral trajectories, where either the sum of the up, down and strange quark masses, or the mass of the strange quark is kept fixed, we extract the light and strange quark mass dependence of the rho meson parameters, and make...

We study in detail the method proposed recently to study the vector–vector interaction using the $N/D$ method and dispersion relations, which concludes that, while, for $J=0$, one finds bound states, in the case of $J=2$, where the interaction is also attractive and much stronger, no bound state is found. In that work, approximations are done for $...

Based on the picture that the $ f_0(1370), f_0(1710), f_2(1270), f'_2(1525), \bar{K}^{*0}_2(1430)$ resonances are dynamically generated from the vector-vector interaction, we study the decays $J/\psi \to \phi (\omega) f_0(1370) [f_0(1710)]$, $J/\psi \to \phi (\omega) f_2(1270) [f'_2(1525)]$, and $J/\psi \to K^{*0} \bar{K}^{*0}_2(1430)$ and make pre...

In a recent paper~\cite{Ablikim:2019pit}, the BESIII collaboration reported the so-called first observation of pure $W$-annihilation decays $D^+_s \to a^+_0(980) \pi^0$ and $D_s^+ \to a^0_0(980)\pi^+$. The measured absolute branching fractions are, however, puzzlingly larger than those of other measured pure $W$-annihilation decays by at least one...

We study in detail the method proposed recently to study the vector-vector interaction using the $N/D$ method and dispersion relations, which concludes that, while for $J=0$, one finds bound states, in the case of $J=2$, where the interaction is also attractive and much stronger, no bound state is found. In that work, approximations are done for $N...

In this work we present the analysis of the energy spectrum from a recent two-flavor ($N_f=2$) lattice QCD calculation for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The lattice simulation was performed for two quark masses corresponding to a pion mass of 315 MeV and 227 MeV. The $\sigma$-meson parameters are extrac...

We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic phase-shifts for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The calculation is performed for two quark masses corresponding to a pion mass of $315\text{ MeV}$ and $227\text{ MeV}$. The $\sigma$-meson parameters are extracted using various param...

We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic phase-shifts for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The calculation is performed for two quark masses corresponding to a pion mass of $315\text{ MeV}$ and $227\text{ MeV}$. The $\sigma$-meson parameters are extracted using various param...

Several lattice QCD simulations of meson-meson scattering in p-wave and Isospin = 1 in Nf = 2 + 1 flavours have been carried out recently. Unitarized Chiral Perturbation Theory is used to perform extrapolations to the physical point. In contrast to previous findings on the analyses of Nf = 2 lattice data, where most of the data seems to be in agree...

Recent $N_f=2+1$ lattice data for meson-meson scattering in $p$-wave and isospin $I=1$ are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. Chiral extrapolations are performed that postdict phase shifts extracted from experiment quite well. In addition, the low-...

Recent $N_f=2+1$ lattice data for meson-meson scattering in $p$-wave and isospin $I=1$ are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. Chiral extrapolations are performed that postdict phase shifts extracted from experiment quite well. In addition, the low-...

Recently, the GWU lattice group has evaluated high-precision phase-shift data for ?? scattering in the I = 1, J = 1 channel. Unitary Chiral Perturbation Theory describes these data well around the resonance region and for different pion masses. Moreover, it allows to extrapolate to the physical point and estimate the effect of the missing KK? chann...

We go in detail around a recent work, where improvements to make the $\rho\rho$ scattering relativistically covariant are made. The paper has a remarkable conclusion that the $J=2$ state disappears with a potential which is much more attractive than for $J=0$, where a bound state is found. We trace this abnormal conclusion to the fact that an "on s...

We examine in detail a recent work (D.~G\"ulmez, U.-G.~Mei\ss ner and J.~A.~Oller, Eur. Phys. J. C 77:460 (2017)), where improvements to make $\rho\rho$ scattering relativistically covariant are made. The paper has the remarkable conclusion that the $J=2$ state disappears with a potential which is much more attractive than for $J=0$, where a bound...

Recently, the GWU lattice group has evaluated high-precision phase-shift data for $\pi\pi$ scattering in the $I = 1$, $J = 1$ channel. Unitary Chiral Perturbation Theory describes these data well around the resonance region and for different pion masses. Moreover, it allows to extrapolate to the physical point and estimate the effect of the missing...

Partial-wave analysis of meson and photon-induced reactions is needed to enable the comparison of many theoretical approaches to data. In both energy-dependent and independent parametrizations of partial waves, the selection of the model amplitude is crucial. Principles of the $S$-matrix are implemented to different degree in different approaches,...

DOI:https://doi.org/10.1103/PhysRevD.94.079901

The ρ(770) meson is the most extensively studied resonance in lattice QCD simulations in two (Nf=2) and three (Nf=2+1) flavor formulations. We analyze Nf=2 lattice scattering data using unitarized chiral perturbation theory, allowing not only for the extrapolation in mass but also in flavor, Nf=2→Nf=2+1. The flavor extrapolation requires informatio...

We develop a method to measure the amount of compositeness of a resonance, mostly made as a bound state of two hadrons, by simultaneously measuring the rate of production of the resonance and the mass distribution of the two hadrons close to threshold. By using different methods of analysis we conclude that the method allows one to extract the valu...

We have investigated the decays of B ¯ 0 → K ¯ * 0 R and B ¯ s 0 → ϕ R with R being the X(4160), Y(3940), Z(3930) and a predicted J = 1 resonances. By using a model in which these states are dynamically generated from the vector-vector interaction, most notably the D * D ¯ * and D s * D ¯ s * states, we predicted five ratios...

The Λ(1405) baryon is diffcult to detect in experiment, absent in many quark model calculations, and supposedly man-ifested through a two-pole structure. Its uncommon properties made it subject to numerous experimental and theoretical studies in recent years. Finite-volume Lattice-QCD eigenvalues for different quark masses were recently reported by...

The $\rho (770)$ meson is the most extensively studied resonance in lattice QCD simulations in two ($N_f=2$) and three ($N_f=2+1$) flavor formulations. We analyze $N_f=2$ lattice scattering data using unitarized Chiral Perturbation Theory, allowing not only for the extrapolation in mass but also in flavor, $N_f=2\to N_f=2+1$. The flavor extrapolati...

We perform a high-precision calculation of the phase shifts for $\pi$-$\pi$ scattering in the I = 1, J = 1 channel in the elastic region using elongated lattices with two mass-degenerate quark favors ($N_f = 2$). We extract the $\rho$ resonance parameters using a Breit-Wigner fit at two different quark masses, corresponding to $m_{\pi} = 226$MeV an...

We perform a high-precision calculation of the phase shifts for $\pi$-$\pi$ scattering in the I = 1, J = 1 channel in the elastic region using elongated lattices with two mass-degenerate quark favors ($N_f = 2$). We extract the $\rho$ resonance parameters using a Breit-Wigner fit at two different quark masses, corresponding to $m_{\pi} = 226$MeV an...

We develop a method to measure the amount of compositeness of a resonance, mostly made as a bound state of two hadrons, by simultaneously measuring the rate of production of the resonance and the mass distribution of the two hadrons close to threshold. By using different methods of analysis we conclude that the method allows one to extract the valu...

If the X(3872), Y(3940) and X(4160) are D*D¯+c.c., D*D¯* and DS*D¯S* molecules, respectively, there should be doubly charmed mesons (D(*)D(*)). In this talk we predict two states with JP = 1⁺ in the charm = 2 sector, one DD* state around 3850 MeV, other D*D* state with mass around 3970 MeV, and other two similar states in the (charm = 2; strangenes...

In this review we give a perspective of the theoretical work done recently on the interpretation of results from $B$, $D$, $\Lambda_b$, $\Lambda_c$ weak decays into final states that contain interacting hadrons, and how it is possible to obtain additional valuable information that is increasing our understanding of hadron interactions and the natur...

In this review we give a perspective of the theoretical work done recently on the interpretation of results from $B$, $D$, $\Lambda_b$, $\Lambda_c$ weak decays into final states that contain interacting hadrons, and how it is possible to obtain additional valuable information that is increasing our understanding of hadron interactions and the natur...

The $\Lambda(1405)$ baryon is difficult to detect in experiment, absent in many quark model calculations, and supposedly manifested through a two-pole structure. Its uncommon properties made it subject to numerous experimental and theoretical studies in recent years. Lattice-QCD eigenvalues for different quark masses were recently reported by the A...

We investigate the decay of ¯ B 0 → ¯ K * 0 R and ¯ B 0 s → φR with R being the X(4160), Y (3940), Z(3930) resonances. Under the assumption that these states are dynamically generated from the vector-vector interaction, as has been concluded from several theoretical studies, we use a reaction mechanism of quark production at the elementary level, f...

Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.

We obtain the width of the $\omega$ meson in dense nuclear matter by taking into account (i) the free decay of the $\omega$ into three pions, which is dominated by $\rho \pi$ mode, (ii) the processes induced by a vector-baryon interaction dominated by vector meson exchange, and (iii) the $\omega \to K \bar K$ mechanism in matter. The $\omega$ meson...

We develop a method to determine accurately the binding energy of the X(3872) from lattice data for the $D \bar D^*$ interaction. We show that, because of the small difference between the neutral and charged components of the X(3872), it is necessary to differentiate them in the energy levels of the lattice spectrum if one wishes to have a precise...

Several observed states close to the $D\bar{D}^*$ and $D^*_{(s)}\bar{D}^*_{(s)}$ thresholds, as the X(3872) and some XYZ particles can be described in terms of a two-meson molecule. Furthermore, doubly charmed states are also predicted. These new states are near the $D^*D^*$ and $D^*D^*_s$ thresholds, % Therefore, if the previous XYZ are molecules,...

In this talk we study dynamically generated resonances from two-vector mesons within the hidden gauge formalism in a coupled channel unitary approach. We focus on the sectors with charm and/or strangeness and double charm, being some of them flavor exotic. Concretely, by looking for poles in the complex plane, we get three poles in the T-matrix aro...

We evaluate the width of the \omega\ meson in nuclear matter. We consider the free decay mode of the \omega\ into three pions, which is dominated by \rho\pi\ decay, and replace the \rho\ and \pi\ propagators by their medium modified ones. We also take into account the quasielastic and inelastic processes induced by a vector-baryon interaction domin...

The properties of strange and charm mesons in nuclear matter and nuclei are reviewed. Different frameworks are presented and discussed paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the in-medium properties of these mesons are also addressed, in particular in connection with the future FAIR...

From a picture of the X(3872) where the resonance is a bound state of D̅ D*-c.c., we evaluate the decay width into the J/ψγ channel, which is sensitive to the internal structure of this state. For this purpose we evaluate the loops through which the X(3872) decays into its components, and the J/ψ and the photon are radiated from these components. W...

We study the vector - vector system including all the possible channels with quantum numbers charm = 0, strangeness = 0 around the energy region of 4000 MeV. New states with hidden charm around 4000MeV have been discovered by the B factories. They are intriguingly close to the {D^*}{bar D^*} and D_s^*bar D_s^* thresholds and do not have the propert...

The properties of strange ($K$, $\bar K$ and $\bar K^*$) and open-charm ($D$, $\bar D$ and $D^*$) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden ga...

After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results f...