arXiv subjects

M. Albaladejo

Publications and source records attributed to M. Albaladejo.

At least 19 recordsLinked to original sources

arXiv2025

Hadron Physics Opportunities at FAIR

This White Paper outlines a coordinated, decade-spanning programme of hadron and QCD studies anchored at the GSI/FAIR accelerator complex. Profiting from intense deuteron, proton and pion beams coupled with high-rate capable detectors and an international theory effort, the initiative addresses fundamental questions related to the strong interaction featuring confinement and dynamical mass generation. This includes our understanding of hadron-hadron interactions and the composition of hadrons through mapping the baryon and meson spectra, including exotic states, and quantifying hadron structure. This interdisciplinary research connects topics in the fields of nuclear, heavy-ion, and (nuclear) astro (particle) physics, linking, for example, terrestrial data to constraints on neutron star structure. A phased roadmap with SIS100 accelerator start-up and envisaged detector upgrades will yield precision cross sections, transition form factors, in-medium spectral functions, and validated theory inputs. Synergies with external programmes at international accelerator facilities worldwide are anticipated. The programme is expected to deliver decisive advances in our understanding of non-perturbative (strong) QCD and astrophysics, and high-rate detector and data-science technology.

hep-ex↗

arXiv2025

Spectroscopic and femtoscopic insights into vector-baryon interactions in the strangeness $-1$ sector

We revisit the strangeness $-1$ sector of the interaction between vector mesons of the $\rho-$nonet and $1/2^+$ ground state baryons ($VB$), within the unitary coupled-channel hidden gauge formalism. We adopt a renormalization scheme that induces a reasonable short-distance behavior of the two-hadron wave functions, which is the major limitation of femtoscopy techniques at this time. We perform an exhaustive spectroscopy study, implementing different improvements and considerations, and find compatibilities between the poles extracted from the present approach, and some of the states listed in the Review of Particle Physics. Finally, we predict several correlation functions (CFs) associated with various meson-baryon pairs in this sector, paying special attention to the distinctive and clear signatures produced by the dynamically generated states. To obtain realistic estimates for the CFs, we have calculated the production weights using the Thermal-FIST package. Such studies will shed light into the odd-parity $\Lambda^*$ and $\Sigma^*$ hadron spectra, up to 2 GeV, and will open the strategy to improve effective field theories by using low-energy constants fitted to femtoscopy data.

hep-ph↗

arXiv2025

$\phi \to 3\pi$ and $\phi\pi^{0}$ transition form factor from Khuri-Treiman equations

This work studies the $\phi \to 3\pi$ decay and the $\phi \to \pi^0 \gamma^\ast$ transition form factor, utilizing the Khuri-Treiman formalism to account for analyticity, crossing, and unitarity. Using once-subtracted dispersion relations, we perform a simultaneous fit to the $\phi \to 3\pi$ Dalitz plot distribution and the $\phi \to \pi^0 \gamma^\ast$ measurements from the KLOE collaboration, finding good agreement with these experimental data. These results reaffirm the applicability of the Khuri-Treiman approach in the analysis of three-body decays. An interesting result is that the subtraction constant appearing in the equations is similar to a sum rule expectation, in contrast to analogous studies of $\omega \to 3\pi$ decays and $\omega \to \pi^0 \gamma^\ast$, which shows significant deviations. Our results also provide a reasonable description of the trend of the transition form factor data from BaBar in the $e^{+}e^{-}\to\phi\pi^{0}$ scattering region. These intriguing theoretical differences between the decays of $\phi$ and $\omega$ could encourage further experimental measurements to assess the discrepancies and refine the theoretical predictions.

hep-ph↗

arXiv2025

Femtoscopy correlation functions and hadron-hadron scattering amplitudes in presence of Coulomb potential

This work addresses the incorporation of Coulomb interactions into femtoscopy correlation functions (CFs) used to probe hadron interactions. Combining strong contact potentials with Coulomb effects, the derived scattering amplitudes and wave functions are used to compute CFs, accounting for both interactions coherently. Next, we analyze the nature of the corrections due to the finite range of the strong interaction, closely linked to off-shell effects, and propose an approximate method to account for them. We show how these corrections turn out to be essential to accurately extract the strong hadron-hadron scattering amplitudes from CF data. We compare the obtained expressions for the CFs with those reported in previous theoretical frameworks. Also, using proton-proton systems as a case study, we obtain a good comparison of our results with previous realistic theoretical calculations and with accurate recent data from the ALICE experiment. The framework enables precise CF calculations without numerical solution of the Schr\"odinger equation, offering a practical tool for femtoscopy analyses involving charged hadrons. In addition, the scheme allows for an easy connection with scattering amplitudes obtained from Effective Field Theories.

hep-ph↗

arXiv2025

Description of femtoscopic correlations with realistic pion-kaon interactions: the $\kappa/K^*_0(700)$ case

In this work, we show how $\pi^+ K_S$ femtoscopic correlations, recently reported by ALICE collaboration in $ pp $ collisions, can be well described taking into account relativistic corrections and using realistic $ \pi K $ interactions. These are obtained from a dispersive analysis of scattering data, which provides an accurate and model-independent description of the $ \kappa/K^*_0(700) $ resonance pole. The chiral symmetry suppression of the $ \pi K $ interactions at low energies and the non-ordinary features of the $ \kappa/K^*_0(700) $ seem to suggest that the $ \pi^+ K_S $ source radius might be surprisingly smaller than for other hadronic processes when using the standard and simple Lednicky-Lyuboshits factorization approximation.

hep-ph↗

arXiv2024

Femtoscopy correlation functions and mass distributions from production experiments

We discuss the relation between the Koonin-Pratt femtoscopic correlation function (CF) and invariant mass distributions from production experiments. We show that the equivalence is total for a zero source-size and that a Gaussian finite-size source provides a form-factor for the virtual production of the particles. Motivated by this remarkable relationship, we study an alternative method to the Koonin-Pratt formula, which connects the evaluation of the CF directly with the production mechanisms. The differences arise mostly from the $T$-matrix quadratic terms and increase with the source size. We study the case of the $D^0 D^{\ast +}$ and $D^+ D^{\ast 0}$ correlation functions of interest to unravel the dynamics of the exotic $T_ {cc}(3875)^+$, and find that these differences become quite sizable already for 1 fm sources. We nevertheless conclude that the lack of coherence in high-multiplicity-event reactions and in the creation of the fire-ball source that emits the hadrons certainly make much more realistic the formalism based on the Koonin-Pratt equation. We finally derive an improved Lednicky-Lyuboshits (LL) approach, which implements a Lorentz ultraviolet regulator that corrects the pathological behaviour of the LL CF in the punctual source-size limit.

hep-ph↗

arXiv2024

Lowest-lying ${\frac{1}{2}}^-$ and ${\frac{3}{2}}^-$ $Λ_{Q}$ resonances: from the strange to the bottom sectors

We present a detailed study of the lowest-lying ${\frac{1}{2}}^-$ and ${\frac{3}{2}}^-$ $Λ_{Q}$ resonances both in the heavy quark (bottom and charm) and the strange sectors. We have paid special attention to the interplay between the constituent quark-model and chiral baryon-meson degrees of freedom, which are coupled using a unitarized scheme consistent with leading-order heavy quark symmetries. We show that the $Λ_b(5912)$ [$J^P=1/2^-$], $Λ_b(5920)$ [$J^P=3/2^-$] and the $Λ_c(2625)$ [$J^P=3/2^-$], and the $Λ(1520)$ [$J^P=3/2^-$] admitting larger breaking corrections, are heavy-quark spin-flavor siblings. They can be seen as dressed quark-model states with $Σ_{Q}^{(*)}π$ molecular components of the order of 30\%. The ${J^P=\frac{1}{2}}^-$ $Λ_c(2595)$ has, however, a higher molecular probability of at least $50$\%, and even values greater than 70\% can be easily accommodated. This is because it is located almost on top of the threshold of the $Σ_cπ$ pair, which largely influences its properties. Although the light degrees of freedom in this resonance would be coupled to spin-parity $1^-$ as in the $Λ_b(5912)$, $Λ_b(5920)$ and $Λ_c(2625)$, the $Λ_c(2595)$ should not be considered as a heavy-quark spin-flavor partner of the former ones. We also show that the $Λ(1405)$ chiral two-pole pattern does not have analogs in the $\frac{1}{2}^-$ charmed and bottomed sectors, because the $ND^{(*)}$ and $N\overline{B}{}^{(*)} $ channels do not play for heavy quarks the decisive role that the $N \overline{K}$ does in the strange sector, and the notable influence of the bare quark-model states for the charm and bottom resonances. Finally, we predict the existence of two $Λ_b(6070)$ and two $Λ_c(2765)$ heavy-quark spin and flavor sibling odd parity states.

hep-ph↗

arXiv2023

Dynamics in near-threshold $J/ψ$ photoproduction

The study of $J/ψ$ photoproduction at low energies has consequences for the understanding of multiple aspects of nonperturbative QCD, ranging from mechanical properties of the proton, to the binding inside nuclei, and the existence of hidden-charm pentaquarks. Factorization of the photon-$c \bar c$ and nucleon dynamics or Vector Meson Dominance are often invoked to justify these studies. Alternatively, open charm intermediate states have been proposed as the dominant mechanism underlying $J/ψ$ photoproduction. As the latter violates this factorization, it is important to estimate the relevance of such contributions. We analyse the latest differential and integrated photoproduction cross sections from the GlueX and $J/ψ$-007 experiments. We show that the data can be adequately described by a small number of partial waves, which we parameterize with generic models enforcing low-energy unitarity. The results suggest a nonnegligible contribution from open charm intermediate states. Furthermore, most of the models present an elastic scattering length incompatible with previous extractions based on Vector Meson Dominance, and thus call into question its applicability to heavy mesons. Our results indicate a wide array of physics possibilities that are compatible with present data and need to be disentangled.

hep-ph↗

arXiv2023

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

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 multi-GeV 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 high-luminosity 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, Hadron-Quark 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.

nucl-ex↗

arXiv2023

Inverse problem in femtoscopic correlation functions: The $T_{cc}(3875)^+$ state

We study here the inverse problem of starting from the femtoscopic correlation functions of related channels and analyze them with an efficient tool to extract the maximum information possible on the interaction of the components of these channels, and the existence of possible bound states tied to this interaction. The method is flexible enough to accommodate non-molecular components and the effect of missing channels relevant for the interaction. We apply the method to realistic correlation functions for the $D^{*+}D^0$ and $D^{*0}D^+$ channels derived consistently from the properties of the $T_{cc}(3875)^+$ and find that we can extract the existence of a bound state, its nature as a molecular state of the $D^{*+}D^0$ and $D^{*0}D^+$ channels, the probabilities of each channel, as well as scattering lengths and effective ranges for the channels, together with the size of the source function, all of them with a relatively good precision.

hep-ph↗

arXiv2023

Ambiguities in Partial Wave Analysis of Two Spinless Meson Photoproduction

We describe the formalism to analyze the mathematical ambiguities arising in partial-wave analysis of two spinless mesons produced with a linearly polarized photon beam. We show that partial waves are uniquely defined when all accessible observables are considered, for a wave set which includes $S$ and $D$ waves. The inclusion of higher partial waves does not affect our results, and we conclude that there are no mathematical ambiguities in partial-wave analysis of two mesons produced with a linearly polarized photon beam. We present Monte Carlo simulations to illustrate our results.

hep-ph↗

arXiv2023

Khuri-Treiman analysis of $J/ψ\toπ^{+}π^{-}π^{0}$

We study the decay $J/ψ\toπ^{+}π^{-}π^{0}$ within the framework of the Khuri-Treiman equations. We find that the BESIII experimental di-pion mass distribution in the $ρ(770)$-region is well reproduced with a once-subtracted $P$-wave amplitude. Furthermore, we show that $F$-wave contributions to the amplitude improve the description of the data in the $ππ$ mass region around 1.5 GeV. We also present predictions for the $J/ψ\toπ^{0}γ^{*}$ transition form factor.

hep-ph↗

arXiv2023

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 and find that it mostly provides information on the scattering length, since the presence of the source function in the correlation function introduces an effective cut in the loop integrals that makes them quite insensitive to the range of the interaction.

hep-ph↗

arXiv2023

Shedding light on the $ X(3930) $ and $ X(3960) $ states with the $B^- \to K^- J/ψω$ 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 $B^- \to K^- J/ψω$ 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 $J/ψω$ mass distribution in the $B^- \to K^- J/ψω$ decay and conclude that a clear signal should be seen around $3930\,\rm MeV$. At the same time, finding no extra resonance signal at $3960\,\rm MeV$ would be a clear indication that there is not a new state at $3960\,\rm MeV$, supporting the hypothesis that the near-threshold peaking structure peak in the $D^{+}_s D^{-}_s$ mass distribution is only a manifestation of a resonance below threshold.

hep-ph↗

arXiv2022

XYZ spectroscopy at electron-hadron facilities II: Semi-inclusive processes with pion exchange

Semi-inclusive processes are very promising to investigate $XYZ$ hadrons at the next generation of electron-hadron facilities, because they generally boast higher cross sections. We extend our formalism of exclusive photoproduction to semi-inclusive final states. The inclusive production cross sections for charged axial-vector $Z$ states from pion exchange are predicted. We isolate the contribution of $Δ$ resonances at small missing mass. Production near threshold is shown to be enhanced roughly by a factor of two compared to the exclusive reaction. We benchmark the model with data of semi-inclusive $b_1^\pm$ production.

hep-ph↗

arXiv2022

Compositeness of S-wave weakly-bound states from next-to-leading order Weinberg's relations

We discuss a model-independent estimator of the likelihood of the compositeness of a shallow S-wave bound or virtual state. The approach is based on an extension of Weinberg's relations in Phys. Rev. 137, B672 (1965) and it relies only on the proximity of the energy of the state to the two-hadron threshold to which it significantly couples. The scheme only makes use of the experimental scattering length and the effective range low energy parameters, and it is shown to be fully consistent for predominantly molecular hadrons. As explicit applications, we analyse the case of the deuteron, the $^1{\rm S}_0$ nucleon-nucleon virtual state and the exotic $D^{\ast}_{s0}(2317)^\pm$, and find strong support to the molecular interpretation in all cases. Results are less conclusive for the $D^{\ast}_{s0}(2317)^\pm$, since the binding energy of this state is significantly higher than that of the deuteron, and the approach employed here is at the limit of its applicability. We also qualitatively address the case of the recently discovered $T_{cc}^+$ state, within the isospin limit to avoid the complexity of the very close thresholds $D^0D^{\ast +}$ and $D^+D^{\ast 0}$, which could mask the ingredients of the approach proposed in this work.

hep-ph↗

arXiv2021

Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report

This report describes the physics case, the resulting detector requirements, and the evolving detector concepts for the experimental program at the Electron-Ion Collider (EIC). The EIC will be a powerful new high-luminosity facility in the United States with the capability to collide high-energy electron beams with high-energy proton and ion beams, providing access to those regions in the nucleon and nuclei where their structure is dominated by gluons. Moreover, polarized beams in the EIC will give unprecedented access to the spatial and spin structure of the proton, neutron, and light ions. The studies leading to this document were commissioned and organized by the EIC User Group with the objective of advancing the state and detail of the physics program and developing detector concepts that meet the emerging requirements in preparation for the realization of the EIC. The effort aims to provide the basis for further development of concepts for experimental equipment best suited for the science needs, including the importance of two complementary detectors and interaction regions. This report consists of three volumes. Volume I is an executive summary of our findings and developed concepts. In Volume II we describe studies of a wide range of physics measurements and the emerging requirements on detector acceptance and performance. Volume III discusses general-purpose detector concepts and the underlying technologies to meet the physics requirements. These considerations will form the basis for a world-class experimental program that aims to increase our understanding of the fundamental structure of all visible matter

physics.ins-det↗

arXiv2021

$T_{cc}^{+}$ coupled channel analysis and predictions

A coupled channel analysis of the $D^{\ast+}D^0$ and $D^{\ast0}D^+$ system is performed to study the doubly charmed $T_{cc}^+$ state recently discovered by the LHCb collaboration. We use a simple model for the scattering amplitude that allows us to describe well the experimental spectrum, and obtain the $T_{cc}^+$ pole in the coupled channel $T$-matrix. 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 $D^0 D^0 π^+$ spectrum alone. Therefore, we use the same formalism to predict other $DDπ$ spectra. In the case the $T_{cc}^+$ has $I=1$, we also predict the location of the other two members ($T_{cc}^{++}$ and $T_{cc}^0$) of the triplet. Finally, using Heavy-Quark Spin Symmetry, we predict the location of possible heavier $D^\ast D^\ast$ ($I=0$ or $I=1$) partners.

hep-ph↗