
Abreu, L. M., Albaladejo, M., Feijoo, A., Oset, E., & Nieves, J. (2023). Shedding light on the X(3930) and X(3960) states with the B> K J/psi omega reaction. Eur. Phys. J. C, 83(4), 309–11pp.
Abstract: We have studied the contribution of the state X(3930), coming from the interaction of the D ($) over bar and Ds(+) D ($) over bar (s) channels, to the B > 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 Ds(+) D s mass distribution around threshold. We present results for what we expect in the J/psi omega mass distribution in the B > K J/psi omega decay and conclude that a clear signal should be seen around 3930 MeV. At the same time, finding no extra resonance signal at 3960 MeV would be a clear indication that there is not a new state at 3960 MeV, supporting the hypothesis that the nearthreshold peaking structure peak in the Ds(+) Ds() mass distribution is only a manifestation of a resonance below threshold.



Accardi, A. et al, Albaladejo, M., Papavassiliou, J., & Passemar, E. (2024). Strong interaction physics at the luminosity frontier with 22 GeV electrons at Jefferson Lab. Eur. Phys. J. A, 60(9), 173–101pp.
Abstract: This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multiGeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in highluminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, HadronQuark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena.



Albaladejo, M. (2022). Tcc(+) coupled channel analysis and predictions. Phys. Lett. B, 829, 137052–13pp.
Abstract: A coupled channel analysis of the D*D+(0) and D*D0(+) system is performed to study the doubly charmed Tcc(+) state recently discovered by the LHCb collaboration. We use a simple model for the scattering amplitude and production mechanism that allows us to describe well the experimental spectrum, and obtain the Tcc(+) pole in the coupled channel Tmatrix. We find that this bound state has a large molecular component. The isospin (I = 0 or I = 1) of the state cannot be inferred from the (DD0)D0 pi(+) spectrum alone, although there is some experimental evidence that points to the I = 0 interpretation. Therefore, we use the same formalism to predict other DD pi spectra. In the case the Tcc(+) has I = 1, we also predict the location of the other two members (Tcc(+) and Tcc(0)) of the triplet. Finally, using HeavyQuark Spin Symmetry, we predict the location of possible heavier D*D* (I = 0 or I= 1) partners.



Albaladejo, M., Bibrzycki, L., Dawid, S. M., FernandezRamirez, C., GonzalezSolis, S., Hiller Blin, A. N., et al. (2022). Novel approaches in hadron spectroscopy. Prog. Part. Nucl. Phys., 127, 103981–75pp.
Abstract: 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 newgeneration 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.



Albaladejo, M., Daub, J. T., Hanhart, C., Kubis, B., & Moussallamd, B. (2017). How to employ (B)overbar(d)(0) > J/psi(pi eta, (K)overbarK) decays to extract information on pi eta scattering. J. High Energy Phys., 04(4), 010–28pp.
Abstract: We demonstrate that dispersion theory allows one to deduce crucial information on pi eta scattering from the finalstate interactions of the light mesons visible in the spectral distributions of the decays (B) over bar (0)(d) > J/psi(pi(0)eta, K+K, K0 (K) over bar (0)). Thus highquality measurements of these differential observables are highly desired. The corresponding rates are predicted to be of the same order of magnitude as those for (B) over bar (0)(d) > J/psi pi(+)pi() measured recently at LHCb, letting the corresponding measurement appear feasible.



Albaladejo, M., FernandezSoler, P., Guo, F. K., & Nieves, J. (2017). Twopole structure of the D0*(2400). Phys. Lett. B, 767, 465–469.
Abstract: The so far only known charmed nonstrange scalar meson is dubbed as D0(*)(2400) in the Review of Particle Physics. We show, within the framework of unitarized chiral perturbation theory, that there are in fact two (I = 1/2, J(P) = 0(+)) poles in the region of the D0(*)( 2400) in the coupledchannel D pi, D eta and Ds (K) over bar scattering amplitudes. With all the parameters previously fixed, we predict the energy levels for the coupledchannel system in a finite volume, and find that they agree remarkably well with recent lattice QCD calculations. This successful description of the lattice data is regarded as a strong evidence for the twopole structure of the D0(*)( 2400). With the physical quark masses, the poles are located at (2105(8)(+6) – i102(12)(+10)) MeV and (2451(26)(+36) – i134(8)(+7)) MeV, with the largest couplings to the D pi and Ds (K) over bar channels, respectively. Since the higher pole is close to the Ds (K) over bar threshold, we expect it to show up as a threshold enhancement in the Ds (K) over bar invariant mass distribution. This could be checked by highstatistic data in future experiments. We also show that the lower pole belongs to the same SU(3) multiplet as the Ds0(*)(2317) state. Predictions for partners in the bottom sector are also given.



Albaladejo, M., FernandezSoler, P., & Nieves, J. (2016). Z(c)(3900): confronting theory and lattice simulations. Eur. Phys. J. C, 76(10), 573–9pp.
Abstract: We consider a recent T matrix analysis by Albaladejo et al. (Phys Lett B 755: 337, 2016), which accounts for the J/psi pi and D*(D) over bar coupledchannels dynamics, and which successfully describes the experimental information concerning the recently discovered Z(c)(3900)(+/). Within such scheme, the data can be similarly well described in two different scenarios, where Z(c)(3900) is either a resonance or a virtual state. To shed light into the nature of this state, we apply this formalism in a finite box with the aim of comparing with recent Lattice QCD (LQCD) simulations. We see that the energy levels obtained for both scenarios agree well with those obtained in the singlevolume LQCD simulation reported in Prelovsek et al. (Phys Rev D 91: 014504, 2015), thus making it difficult to disentangle the two possibilities. We also study the volume dependence of the energy levels obtained with our formalism and suggest that LQCD simulations performed at several volumes could help in discerning the actual nature of the intriguing Z(c)(3900) state.



Albaladejo, M., FernandezSoler, P., Nieves, J., & Ortega, P. G. (2018). Contribution of constituent quark model c(s)overbar states to the dynamics of the D*s0 (2317) and Ds1(2460) resonances. Eur. Phys. J. C, 78(9), 722–22pp.
Abstract: The masses of the D*(s0) (2317) and Ds1(2460) resonances lie below the DK and D* K thresholds respectively, which contradicts the predictions of naive quark models and points out to nonnegligible effects of the D(*) K loops in the dynamics of the evenparity scalar (J(pi) = 0(+)) and axialvector (J(pi) = 1(+)) c (s) over bar systems. Recent lattice QCD studies, incorporating the effects of the D(*) K channels, analyzed these spinparity sectors and correctly described the D*(s0)(2317) – Ds1(2460) mass splitting. Motivated by such works, we study the structure of the D*(s0)(2317) and Ds1(2460) resonances in the framework of an effective field theory consistent with heavy quark spin symmetry, and that incorporates the interplay between D(*) K mesonmeson degrees of freedom and bare Pwave c (s) over bar states predicted by constituent quark models. We extend the scheme to finite volumes and fit the strength of the coupling between both types of degrees of freedom to the available lattice levels, which we successfully describe. We finally estimate the size of the D(*) K twomeson components in the D*(s0)(2317) and Ds1(2460) resonances, and we conclude that these states have a predominantly hadronicmolecular structure, and that it should not be tried to accommodate these mesons within c (s) over bar constituent quark model patterns.



Albaladejo, M., FernandezSoler, P., Nieves, J., & Ortega, P. G. (2017). Lowestlying evenparity (B)overbar(s) mesons: heavyquark spinflavor symmetry, chiral dynamics, and constituent quarkmodel bare masses. Eur. Phys. J. C, 77(3), 170–9pp.
Abstract: The discovery of the D*(s0)(2317) and Ds1(2460) resonances in the charmedstrange meson spectra revealed that formerly successful constituent quark models lose predictability in the vicinity of twomeson thresholds. The emergence of nonnegligible effects due to meson loops requires an explicit evaluation of the interplay between Q (q) over bar and (Q (q) over bar)(q (q) over bar) Fock components. In contrast to the c (s) over bar sector, there is no experimental evidence of J(P) = 0(+), 1(+) bottomstrange states yet. Motivated by recent lattice studies, in this work the heavyquark partners of the D*(s0)(2317) and Ds1(2460) states are analyzed within a heavy meson chiral unitary scheme. As a novelty, the coupling between the constituent quarkmodel Pwave (B) over bar (s) scalar and axial mesons and the (B) over bar (()*()) K channels is incorporated employing an effective interaction, consistent with heavyquark spin symmetry, constrained by the lattice energy levels.



Albaladejo, M., GonzàlezSolís, S., Bibrzycki, L., FernándezRamírez, C., Hammoud, N., Mathieu, V., et al. (2023). KhuriTreiman analysis of J/Psi > pi+ pipi0. Phys. Rev. D, 108(1), 014035–11pp.
Abstract: We study the decay J=& psi; & RARR; & pi; thorn & pi;& pi;0 within the framework of the KhuriTreiman equations. We find that the BESIII experimental dipion mass distribution in the & rho;o770 thorn region is well reproduced with a oncesubtracted Pwave amplitude. Furthermore, we show that Fwave contributions to the amplitude improve the description of the data in the & pi;& pi; mass region around 1.5 GeV. We also present predictions for the J=& psi; & RARR; & pi;0 & gamma;* transition form factor.

