arXiv subjects

Miguel Albaladejo

Publications and source records attributed to Miguel Albaladejo.

At least 19 recordsLinked to original sources

arXiv2026

A femtoscopic tale of two $C$-parities: the $Z_c(3900)$ and the isovector partner of the $X(3872)$

Understanding the nature of the exotic $Z_c(3900)$ and $Z_{cs}(3985)$ states, and searching for the predicted isovector partner $W_{c1}$ of the $X(3872)$, remain central challenges in exotic-hadron spectroscopy. We investigate the femtoscopic correlation functions (CFs) of the $D^{(\ast)0}D_{(s)}^{(\ast)-}$ systems. Since these charm-meson--antimeson pairs are not $G$-parity eigenstates, their CFs contain contributions from both the $C$-odd and $C$-even sectors, providing direct access to the dynamics underlying the $Z_c$, $Z_{cs}$, and the predicted isovector exotic $W_{c1}$. Within a heavy-quark-spin-symmetric coupled-channel framework, we show that the $C$-even admixture enhances the low-momentum CFs by more than $2.5σ$ in the vicinity of their thresholds. Free from Coulomb distortions and accessible in high-multiplicity $pp$ collisions at the LHC, these channels offer the first direct femtoscopic probe of the isovector $C$-even sector and of the elusive $W_{c1}$ state.

hep-ph↗

arXiv2026

Coulomb Effects in Momentum-Space Femtoscopy: A Case Study of the $\bar{K}Ω$ System

We present a momentum-space framework for the consistent treatment of Coulomb interactions in femtoscopic correlation functions based on a modified Vincent--Phatak method that is more amenable to numerical implementation. The formalism provides a practical approach to incorporating Coulomb effects at the short distances relevant for femtoscopy within the Lippmann--Schwinger equation, while preserving a unified treatment of the strong interaction. As an application, we study the $S=-4$ pseudoscalar--baryon decuplet interaction in the $\bar{K}Ω$ system and present predictions for the singly and doubly negatively charged channels, $\bar{K}^0Ω^-$ and $K^-Ω^-$. As an additional validation of the formalism, we have also applied it to the well-studied $pp$ system. We further assess the limitations of the asymptotic wave-function approximation and quantify corrections accounting for the short-distance structure of the interaction potential. We introduce a phenomenological parameter that effectively absorbs contributions from both the finite source size and the off-shell structure of the interaction, the latter being one of the main obstacles to extracting detailed information on hadron--hadron interactions from femtoscopic measurements in a model-independent way.

hep-ph↗

arXiv2026

Signatures of the $Ω(2012)^{-}$ state in $Ξ^*\bar K$ Correlation Functions

We investigate the $Ω(2012)$ resonance in the strangeness $S=-3$ sector within a coupled-channel chiral unitary approach and present the first quantitative predictions for femtoscopic correlation functions directly sensitive to its dynamics. The $Ω(2012)$ is dynamically generated as a quasi-bound $Ξ^{\ast}\bar K$-$Ωη$ molecular state, with its coupling to the $Ξ\bar{K}$ channel driven by $d$-wave transitions. Model parameters are constrained by the measured mass, width, and the Belle determination of the branching fraction $\mathcal R^{Ξ\bar Kπ}_{Ξ\bar K}$, yielding $M_{Ω(2012)}=(2012.53\pm0.73)$ MeV and $Γ_{Ω(2012)}=(4.05\pm0.13)$ MeV. Within this framework, we compute the femtoscopic correlation functions of the $Ξ^{\ast0}K^-$, $Ξ^{\ast-}\bar K^0$, and $Ω^-η$ systems. The $Ξ^{\ast}\bar K$ correlation functions exhibit pronounced near-threshold structures that arise from the proximity of the $Ω(2012)$ pole, demonstrating an exceptional sensitivity to its position and coupled-channel composition. In particular, the $Ξ^{\ast0}K^-$ correlation function is identified as a clean and highly selective probe of the $Ω(2012)$ resonance. These results establish femtoscopic correlation measurements as powerful tools for extracting resonance properties beyond conventional invariant-mass analyses and provide concrete theoretical benchmarks for upcoming experimental studies aimed at elucidating the molecular nature of the $Ω(2012)$.

hep-ph↗

arXiv2025

Melting down a tetraquark: $D^{\ast}D^{(\ast)}$ interactions and $T_{cc}(3875)^+$ in a hot environment

We discuss the modification of the properties of the tetraquark-like $T_{cc}(3875)^+$ and its heavy quark spin partner, $T_{cc}(4016)^{*+}$ immersed in a hot bath of pions. We consider these exotic states as purely isoscalar $DD^\ast$ and $D^\ast D^\ast$ $S$-wave bound states, respectively. Finite temperature effects are incorporated through the $D$ and $D^\ast$ state-of-the-art thermal spectral functions calculated in [G. Montana et al., Phys. Rev. D, 102 (2020) 096020], using the imaginary-time formalism. We find important modifications of the $DD^\ast$ and $D^\ast D^\ast$ scattering amplitudes already for $T=80$ MeV, and show that the hot-bath lineshapes of these tetraquark-like states strongly depend on their Weinberg molecular content. We find that the thermal $T_{cc}(3875)^+$ and $T_{cc}(4016)^{*+}$ spectral functions change more rapidly with temperature for high molecular probabilities $P_0$. For large values of $P_0$, the widths significantly increase with temperature, leading to the melting of these exotic states for temperatures larger than 80 MeV. For small molecular components, the changes in the spectral functions of these states due to temperature become significantly less important. All these results show that any future experimental determination of the $D^{(\ast)}D^*$ scattering amplitudes at finite temperature will provide valuable insights into the molecular content of the $T_{cc}(3875)^+$ and $T_{cc}(4016)^{*+}$ exotics.

hep-ph↗

arXiv2025

Signatures of Odd-Parity $s$-wave $Ξ^*$ States in Femtoscopic Correlation Functions

We investigate the $Ξ^*$ resonances within the molecular picture, where these states are dynamically generated as poles in the unitarized scattering amplitudes arising from the coupled-channel interactions of $K^{*-} Λ$, $K^{*-} Σ^0$, $ρ^- Ξ^0$, $\overline{K}{}^{*0} Σ^-$, $ρ^0 Ξ^-$, $ωΞ^-$, and $ϕΞ^-$. The interaction kernel is derived from the local hidden gauge formalism, while the unitarization procedure employs a hybrid method that combines cutoff and dimensional regularizations in the evaluation of the loop function. From a detailed spectroscopic analysis, we identify two $S = -2$ baryon states whose properties are compatible with some of the $Ξ^*$ resonances listed in the Review of Particle Physics. To explore their possible experimental signatures, we compute the femtoscopic correlation functions for all the vector-baryon pairs considered in the present study, using realistic estimates of production weights and varying source sizes $R = 1, 1.1, 1.2, 1.3, 1.5$ fm.

hep-ph↗

arXiv2025

The role of chiral symmetry and the non-ordinary $κ/K^*_0(700)$ nature in $π^\pm K_S$ femtoscopic correlations

We show that the use of realistic $πK$ interactions, obtained from a dispersive analysis of scattering data, as well as relativistic corrections, are essential to describe recently observed $π^\pm K_S$ femtoscopic correlations. We demonstrate that the spontaneous chiral symmetry breaking dynamics and the non-ordinary features of the $κ/K^*_0(700)$ resonance, together with large cancellations between isospin channels, produce a large suppression of $π^\pm K_S$ femtoscopic correlations compared to widely used models. Within an improved version of the standard on-shell factorization formalism, we illustrate that compensating for this interaction suppression leads to source radii smaller than 1 fm, contrary to usual expectations, as well as larger correlation strengths. The relation between these two parameters cannot be accommodated within naive models describing the nature of the resonances. This may raise concerns about the applicability of popular but too simple approaches for systems with light mesons. However, the correlation-suppression effects we demonstrate here will be relevant in any formalism, and substantial corrections may be expected for other femtoscopic systems involving light mesons.

hep-ph↗

arXiv2025

Testing the nature of the $Σ^*(1430)$

We study the feasibility of having the $Σ^*(1430)$ state, predicted within the chiral unitary approach and recently reported by the Belle Collaboration, as corresponding to a state of non-molecular nature. Starting from this assumption, since the state is observed in the $πΛ$ channel, we allow the coupling to this state and relate the coupling to $\bar K N$ and $πΣ$ using $SU(3)$ symmetry arguments. We find that it is possible to have such a state with negligible coupling to the molecular components with a bare mass of the state very close to the physical mass of the $Σ^*(1430)$. Yet, this has consequences on other observables, since the width obtained is extremely small and incompatible with the Belle observations, and it leads to abnormally large values of the $\bar K N$ effective range. Conversely, such mismatches do not appear for large values of the bare mass of the state, but in this case we observe that the state develops large molecular components. While one can rule out a largely non-molecular nature for this state, its properties and detailed nature will need further experimental developments which one can anticipate will be coming in the near future.

hep-ph↗

arXiv2025

$P$-wave charmonium contribution to hidden-charm states from reanalysis of lattice QCD data

We reanalyze, considering the contribution of $P$-wave charmonia, lattice data for the $D \bar{D}$-$D_s\bar{D}_s$ coupled-channel of S. Prelovsek et al. [JHEP 06, 035 (2021)] and $D\bar{D}^*$ systems of S. Prelovsek et al. [Phys. Rev. Lett. 111, 192001 (2013)] with $m_π\simeq 280$ and $266$ MeV, and $L=24a/32a$ ($a\simeq 0.09$ fm) and $L=16a$ ($a\simeq0.1239(13)$ fm), respectively. The hidden-charm states with $J^{PC}=0^{++}$, $1^{++}$, and $2^{++}$ quantum numbers are then searched for. For $0^{++}$, the analysis reveals three poles in the $D\bar{D}$-$D_s\bar{D}_s$ coupled-channel amplitude, corresponding to three states. Two of these poles, located near the $D\bar{D}$ and $D_s\bar{D}_s$ thresholds, can be interpreted as mostly molecular states. A third pole above the $D_s\bar{D}_s$ threshold is originated from the $P$-wave $χ_{c0}(2P)$ charmonium state. The number of poles found in the $D\bar D$-$D_s \bar D_s$ system is the same as that found in the original lattice analysis though the position of the third pole changes sizeably. In the $1^{++}$ sector, we find two poles in the complex energy plane. The first one is related to the molecular $X(3872)$ state, with a compositeness exceeding $90\%$, while the second one, stemming from the $χ_{c1}(2P)$ charmonium, appears above the $D\bar{D}^*$ threshold and it likely corresponds to the recently discovered $χ_{c1}(4010)$ state. In the $2^{++}$ sector, we also report two poles and find that the dressed $χ_{c2}(2P)$ is lighter than the $D^*\bar{D}^*$ molecular state, with the dynamics of the latter closely related to that of the heavy-quark spin-symmetry partner of the $X(3872)$. Our exploratory study of the $1^{++}$ and $2^{++}$ sectors offers valuable insights into their dynamics, but given that the fits that we carry out are underconstrained, more lattice data are required to draw robust conclusions.

hep-ph↗

arXiv2025

Charge-conjugation asymmetry and molecular content: the $D_{s0}^\ast(2317)^\pm$ in matter

We analyze the modifications that a dense nuclear medium induces in the $D_{s0}^\ast(2317)^\pm$ and $D_{s1}(2460)^\pm$. In the vacuum, we consider them as isoscalar $D^{(*)}K$ and $\overline{D}{}^{(*)}\overline{K}$ $S$-wave bound states, which are dynamically generated from effective interactions that lead to different Weinberg compositeness scenarios. Matter effects are incorporated through the two-meson loop functions, taking into account the self energies that the $D^{(*)}$, $\overline{D}{}^{(*)}$, $K$, and $\overline{K}$ develop when embedded in a nuclear medium. Although particle-antiparticle [$D^{(\ast)}_{s0,s1}(2317,2460)^+$ versus $D^{(\ast)}_{s0,s1}(2317,2460)^-$] lineshapes are the same in vacuum, we find extremely different density patterns in matter. This charge-conjugation asymmetry mainly stems from the very different kaon and antikaon interaction with the nucleons of the dense medium. We show that the in-medium lineshapes found for these resonances strongly depend on their $D^{(*)}K$/$\overline{D}{}^{(*)}\overline{K}$ molecular content, and discuss how this novel feature can be used to better determine/constrain the inner structure of these exotic states.

hep-ph↗

arXiv2025

On the determination of the $D$ meson width in the nuclear medium with the transparency ratio

We have studied the feasibility of the experimental determination of the width of a $D$ meson in a nuclear medium by using the method of the nuclear transparency. The cross section for inclusive production of a $D^+$ in different nuclei is evaluated, taking care of the $D^+$ absorption in the nucleus, or equivalently, the survival probability of the $D^+$ in its way out of the nucleus from the point of production. We use present values of the in medium width of $D$ mesons and calculate ratios of the cross sections for different nuclei to the $^{12} \text{C} $ nucleus as reference. We find ratios of the order of $0.6$ for heavy nuclei, a large deviation from unity, which indicates that the method proposed is adequate to measure this relevant magnitude, so far only known theoretically.

nucl-th↗

arXiv2024

Study of possible $DND^*$ bound states

We start from a recently favored picture in which the $Λ_c(2940)$ and $Λ_c(2910)$ correspond mostly to $ND^*$ bound states with $J^P = 1/2^-,\, 3/2^-$ and then add a $D$ as a third particle, looking for the possible binding of the $DND^*$ three body system within the framework of the Fixed Center Approximation. We find that the system is bound with respect to the corresponding $Λ_c^* D$ threshold with a binding of about $60$ MeV and a width of about $90$ MeV. Alternatively we assume a cluster of $ND$ and a $D^*$ meson interacting with the cluster and we find similar results. The observation of these states of $J^P = 1/2^+,\, 3/2^+$ would provide new and valuable information concerning the $DN$ and $D^* N$ interaction, an issue of current debate.

hep-ph↗

arXiv2023

Properties of the $T_{cc}(3875)^+$ and the $T_{\bar c \bar c}(3875)^-$ states in nuclear matter

Since its first detection, the interesting properties of the $T_{cc}(3875)^+$ have made it to be one of the most prominent tetraquark-like states up to date. In this work we present a joint analysis of the $T_{cc}^+$ and its charge-conjugated partner in a dense nuclear medium. We start by considering both states as purely isoscalar $D^{\ast} D$ and $\overline{D}{}^{\ast} \overline{D}$ $S$-wave bound states, respectively. We use previous results for the in-medium $D$, $\overline{D}$, $D^\ast$ and $\overline{D}{}^\ast$ spectral functions to determine the modified two-meson amplitudes. We find important changes in the in-medium mass and width of both tetraquark-like resonances, which become more visible when increasing the nuclear density and molecular probabilities. The experimental confirmation of the found distinctive patterns will support the existence of molecular components in the $T_{cc}^+$ and $T_{\bar c\bar c}^-$ wave functions.

hep-ph↗

arXiv2023

Properties of the $T_{cc}(3875)^+$ and $T_{\bar c\bar c}(3875)^-$ (and their heavy-quark spin partners) in nuclear matter

We discuss the modification of the properties of the tetraquark-like $T_{cc}(3875)^+$ and $T_{\bar c\bar c}(3875)^-$ states in dense nuclear matter. We consider the $T_{cc}^+$ and $T_{\bar c\bar c}^-$ in vacuum as purely isoscalar $D^{\ast} D$ and $\overline{D}{}^{\ast} \overline{D}$ $S$-wave bound states, respectively, dynamically generated from a heavy-quark effective interaction between the charmed mesons. We compute the $D$, $\overline{D}$, $D^*$, and $\overline{D}{}^{*}$ spectral functions embedded in a nuclear medium and use them to determine the corresponding $T_{cc}^+$ and $T_{\bar c\bar c}^-$ self energies and spectral functions. We find important modifications of the $D^{\ast} D$ and $\overline{D}{}^{\ast} \overline{D}$ scattering amplitudes and of the pole position of these exotic states already for $ρ_0/2$, with $ρ_0$ the normal nuclear density. We also discuss the dependence of these results on the $D^{\ast} D$ ($\overline{D}{}^{\ast} \overline{D}$) molecular component in the $T_{cc}^+$ ($T_{\bar c\bar c}^-$ ) wave-function. Owing to the different nature of the $D^{(*)}N$ and $\overline{D}{}^{(*)}N$ interactions, we find characteristic changes of the in-medium properties of the $T_{cc}(3875)^+$ and $T_{\bar c\bar c}(3875)^-$, which become increasingly visible as the density increases. The experimental confirmation of the found distinctive density-pattern will give support to the molecular picture of these tetraquark-like states, since in the case they were colourless compact quark structures the density behaviour of their respective nuclear medium spectral functions would likely be similar. Finally, we perform similar analyses for the isoscalar $J^P=1^+$ heavy-quark spin symmetry partners of the $T_{cc}^+$ ($T_{cc}^{*+}$) and the $T_{\bar c\bar c}^-$ ($T_{\bar c\bar c}^{*-}$) by considering the $D^{*0}D^{*+}$ and $\overline{D}{}^{*0} D^{*-}$ scattering $T-$matrices.

hep-ph↗

arXiv2023

Femtoscopic signatures of the lightest S-wave scalar open-charm mesons

We predict femtoscopy correlation functions for $S$--wave $D_{(s)}ϕ$ pairs of lightest pseudoscalar open charm mesons and Goldstone bosons from next-to-leading order unitarized heavy-meson chiral perturbation theory amplitudes. The effect of the two-state structure around $2300\,\text{MeV}$ can be clearly seen in the $(S,I)=(0,1/2)$ $Dπ$, $Dη$, $D_s \overline{K}$ correlation functions, while in the scalar-strange $(1,0)$ sector, the $D^\ast_{s0}(2317)^{\pm}$ state lying below the $DK$ threshold produces a depletion of the correlation function near threshold. These exotic states owe their existence to the nonperturbative dynamics of Goldstone-boson scattering off $D_{(s)}$. The predicted correlation functions could be experimentally measured and will shed light into the hadron spectrum confirming that it should be viewed as more than a collection of quark model states.

hep-ph↗

arXiv2023

Understanding the $0^{++}$ and $2^{++}$ charmonium(-like) states near 3.9 GeV

We propose that the $X(3915)$ observed in the $J/ψ\,ω$ channel is the same state as the $χ_{c2}(3930)$, and the $X(3960)$, observed in the $D_s^+D_s^-$ channel, is an $S$-wave $D_s^+ D_s^-$ hadronic molecule. In addition, the $J^{PC}=0^{++}$ {component in the $B^+\to D^+D^-K^+$} assigned to the $X(3915)$ in the current {\it Review of Particle Physics} has the same origin as the $X(3960)$, which has a mass around 3.94~GeV. To check the proposal, the available data in the $D\bar D$ and $D_s^+ D_s^-$ channels from both $ B$ decays and $γγ$ fusion reaction are analyzed considering both the $D\bar D$-$D_s\bar D_s$-$D^*\bar D^*$-$D_s^*\bar D_s^*$ coupled channels with $0^{++}$ and a $2^{++}$ state introduced additionally. It is found that all the data in different processes can be simultaneously well reproduced, and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73, 3.94, 3.99 and 4.23~GeV, respectively. The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.

hep-ph↗

arXiv2022

Establishing the heavy quark spin and light flavor molecular multiplets of the $X(3872)$, $Z_c(3900)$ and $X(3960)$

Recently, the LHCb Collaboration reported a near-threshold enhancement, $X(3960)$, in the $D_s^+D_s^-$ invariant mass distribution. We show that the data can be well described by either a bound or a virtual state below the $D_s^+D_s^-$ threshold. The mass given by the pole position is $(3928\pm3)$ MeV. Using this mass and the existing information on the $X(3872)$ and $Z_c(3900)$ resonances, a complete spectrum of the $S$-wave hadronic molecules formed by a pair of ground state charmed and anticharmed mesons is established. Thus, pole positions of the partners of the $X(3872)$, $Z_c(3900)$ and the newly observed $D_s^+D_s^-$ state are predicted. Calculations have been carried out at the leading order of nonrelativistic effective field theory and considering both heavy quark spin and light flavor SU(3) symmetries, though conservative errors from the breaking of these symmetries are provided.

hep-ph↗

arXiv2022

Novel approaches in Hadron Spectroscopy

The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.

hep-ph↗

arXiv2022

A combined analysis of the $Z_c(3900)$ and the $Z_{cs}(3985)$ exotic states

We have performed a combined analysis of the BESIII data for both the $Z_c(3900)$ and $Z_{cs}(3985)$ structures, assuming that the latter is an SU(3) flavor partner of the former one. We have improved on the previous analysis of Albaladejo $et$ $al.$ [Phys. Lett. B 755, 337 (2016)] by computing the amplitude for the $D_1\bar{D}D^*$ triangle diagram considering both $D$ and $S$-wave $D_1D^*π$ couplings. We have also investigated effects from SU(3) light-flavor violations, which are found to be moderate and of the order of 20%. The successful reproduction of the BESIII spectra, in both the hidden-charm and hidden-charm strange sectors, strongly supports that the $Z_{cs}(3985)$ and $Z_c(3900)$ are SU(3) flavor partners placed in the same octet multiplet. The best results are obtained when an energy-dependent term in the diagonal $D^{(*)}\bar D_{(s)}^{(*)}$ interaction is included, leading to resonances (poles above the thresholds) to describe these exotic states. We have also made predictions for the isovector $Z_{c}^*$ and isodoublet $Z_{cs}^*$, $D^*\bar{D}^*$ and $D^*\bar{D}_{s}^*$ molecules, with $J^{PC}=1^{+-}$ and $J^{P}=1^{+}$, respectively. These states would be heavy-quark spin symmetry partners of the $Z_{c}$ and $Z_{cs}$. Besides the determination of the masses and widths of the $Z_c(3900)$ and $Z_{cs}(3985)$, we also predict those of the $Z_c^*$ and $Z_{cs}^*$ resonances.

hep-ph↗