Vol. 3 No. 3 (2022): Suplemento de la Revista Mexicana de Física. 19th International conference on hadron spectroscopy and structure in memoriam Simon Eidelman

The Conference was dedicated to Simon Eidelman (1948-2021). Simon was a beloved member of the hadron physics community and the International Advisory Committee of this conference. He encouraged and supported young researchers, and his scientific contributions to the field were numerous, important, and will have a lasting impact in future generations. He will be deeply missed.

One of the unresolved questions in Hadron Physics comes from the field of Baryon Spectroscopy. Here, the exact interaction between the quarks inside the nucleons is investigated via measurement of the excitation spectrum of the nucleons. Comparison to constituent quark models as well as lattice QCD calculations reveal substantial differences is the number of observed states and in the mass hierarchy of the first excitations. This proceeding will give a short recap about the current developments in the field of Light Baryon Spectroscopy.

Photoproduction experiments are a key tool in the investigation of the spectrum of hadronic states and the way gluons contribute to this spectrum. The GlueX experiment, located at Jefferson Lab, features a linearly polarized tagged photon beam and its detector system is optimized to measure a wide range of neutral and charged final states. GlueX offers unique capabilities to study the spectrum of hadrons and is dedicated to the search for hybrid mesons, states with gluonic degrees of freedom. This talk presents first results from our initial campaign of data taking which finished in 2018.

Lattice QCD already offers the possibility of extracting three-hadron scattering quantities from first principles. In the last few years, significant progress has been achieved in developing and applying the finite-volume three-body formalism. The formalism is now able to treat physically relevant systems of three mesons, including those with resonances, as well as three-body decays. In this talk, I will review the state of the art, and comment on recent applications to lattice QCD data for systems of three pions and kaons.

Recent high-quality data sets from various experiments grant new insights into the excitation spectrum of light mesons, which are composed of up, down, and strange quarks. In the non-strange light-meson sector, many recent experimental and theory efforts are focused on the search for so-called exotic states, which are states beyond the na¨ıve constituent quark-model. To this end, various potential decay modes of exotic states are studied at experiments such as GlueX or COMPASS. In addition, there is recent progress in the understanding of so-called non-resonant processes, which act as background in searches for light mesons, as well as in the prediction of light mesons from lattice QCD. While the non-strange light-meson spectrum is already mapped out rather well, many predicted strange mesons have not yet been observed experimentally or need further confirmation. Recent high-precision data from experiments such as LHCb and BESIII allow us to study strange mesons in heavy-meson decays. Alternatively, strange mesons are studied in diffractive scattering of high-energy kaon beams. The so far world’s largest data set on the diffractively produced K−π −π + final state was measured by the COMPASS experiment. A recent analysis of this data covers a large variety of strange mesons over a wide mass range in a single, self-consistent analysis

The BESIII experiment is using e+ e- annihilation in the tau-charm region to study various topics in hadron physics, from the spectroscopy of light and charmonium hadrons, studies on rare and symmetry violating decays to open-charm physics. An overview over a selection of recent BESIII contributions to the field of hadron physics is given, highlighted by the recent observation of a near threshold enhancement in the recoil mass of the K+ in the process e+ e- --> K+ (Ds- D*0 + Ds*- D0)  as a possible Zcs candidate.

We present a dispersion theoretical analysis on recent date from electron-proton scattering. This allows for a high-precision extraction of the electric and magnetic radius of the proton, $r_E = (0.839\pm 0.002{}^{+0.002}_{-0.003})$~fm and $r_M = (0.846\pm 0.001{}^{+0.001}_{-0.005})$~fm, where the first error refers to the statistical type estimated from the bootstrap method, and the second one refers to the systematic uncertainty related to the underlying spectral functions.

The muon g-2 anomaly showing about 4σ deviation between the Standard Model (SM) prediction and the experiment is one of the most promising signals for physics beyond the SM. Also the hadronic uncertainties are limiting the accuracy of the SM prediction. We present the role of recent results, obtained with CMD-3, SND, and KEDR detectors at e +e − colliders VEPP-2000 (0.15÷1 GeV/beam) and VEPP-4M (1÷5 GeV/beam) in Novosibirsk, Russia, in improving the evaluations of hadronic vacuum polarization.

One of the biggest challenges in contemporary physics is understanding the origin and dynamics of the internal structure of hadrons which, at a fundamental level, is described by quantum chromodynamics (QCD). Taking great prominence amongst hadrons are pions and kaons which, despite being the lightest hadrons in nature, their very existence is intimately connected to those mechanisms responsible for almost all of the mass of the visible matter. In this manuscript we discuss many aspects of the pion and kaon structure via light front wave functions and generalized parton distributions, and a collection of other distributions and structural properties that are inferred therefrom.

The recently approved NA66/AMBER experiment (Apparatus for Meson and Baryon Experimental Research) at the CERN Super Proton Synchrotron pursues a broad research program in quantum chromodynamics. It ranges in its first phase from a precision measurement of the proton radius with a 100 GeV muon beam to investigating the quark-gluon structure of mesons in Drell-Yan processes. In a second phase, radio-frequency separated kaon beams will allow to extend such investigations to the strangeness sector.

Simon Eidelman, our colleague and friend, well known physicist in the particle physics world, passed away on June 28, 2021. This reports is about his way in particle physics and his contribution to many areas and researches in our field of physics.

Using a variational approach we calculate the mass spectra of the bottom mesons in the framework of the phenomenological quark anti-quark potential. Decay constant and Leptonic decay widths of the bottom mesons are also calculated. The obtained results are compared with the available experimental data and other theoretical predictions.

The strangeonium state φ(2170) is studied and presented. The processes of e +e − → K+K−, e +e − → K0 SK0 L, e +e − → φK+K− /K+K−K+K−, e +e − → φη, e +e − → φη0 , e +e − → K+K−π 0π 0 and e +e − → ωη are investigated. And the cross sections are measured precisely in the center-of-mass (c.m.) energy region from 2.00 to 3.08 GeV. The parameters of φ(2170) have been extracted from the lineshapes where applicable

Recent results in meson spectroscopy with the CMS detector are presented. In particular, the first observation by the CMS Collaboration of two excited B + c states and the measurement of the B + c (2S) mass using proton-proton collisions at a center-of-mass energy of 13 TeV are reported.

According to lattice simulations and other theoretical approaches, the scalar glueball is the lightest state in the Yang-Mills sector of QCD. Since within this sector the scalar glueball is stable, the scattering between two glueballs is a well-defined process. Moreover, a glueball-glueball bound state, called glueballonium, might exist if the attraction turns out to be large enough. In this work, we concentrate on the formation of the glueballonium in the context of the dilaton potential. In particular, we investigate the parameter values for which such a glueballonium emerges.

Using the large C OMPASS data set on diffractive three pion production, we investigate the contradictory observations reported by previous experiments on the existence of a resonance signal in the spin-exotic wave with spin, parity and charge conjugation quantum numbers 1−+ . We identify a strong dependence of the result on the employed analysis model as the cause and derive a model tuned to minimize these effects. Additionally, we study the robustness of our analysis model using the approach of freed-isobar partial-wave analysis.

We have studied the dominant one-photon radiative transitions of the charmonium ground and orbitally excited states within an analytic confinement model. Along with two fixed basic model parameters (mc and the cutoff value λ), we introduced only one adjustable parameter common to charmonium states: ηc, J/ψ, χc0, χc1, hc and χc2 to parameterize the quark distribution inside the hadron. Our estimates are in good agreement with the latest data.

Motivated by the non-holographic phenomenology, where the mesonic constituent mass breaks linearity in Regge trajectories, we discuss how to implement nonlinear Regge trajectories by deforming the static (monoparametric) quadratic dilaton into a non-quadratic one. This deformation adds an extra parameter into the dilaton, which measures the constituent mass effect, accounting for nonlinearity in the hadronic trajectory. We applied this model to the description of the isovector multiplet spectrum. The set of isovector parameters defines a set of hadronic calibration curves for the dilaton slope and linearity deviation parameter, allowing us to extrapolate the model to other vector states, such as heavy-light mesons or vector non-qq¯ hadrons. In other words, this approach allows us to consider the hadronic inner structure by modifying the dilaton profile.

The precision of lattice QCD calculations has been steadily improving for some time and is now approaching, or has surpassed, the 1% level for multiple quantities. At this level QED effects, i.e. the fact that quarks carry electric as well as color charge, come into play. In this report we will summarise results from the first lattice QCD+QED computations of the properties of ground-state charmonium and bottomonium mesons by the HPQCD Collaboration.

In this contribution we present results of the calculations of several hadronic spectra within the holographic graviton soft-wall (GSW) model. In particular, we studied and compared with data for the ground state and excitations of: glueballs, scalar, vector, axial and pseudo-scalar mesons. The GSW model is found to be capable to describe these observable with only few parameters.

The COMPASS experiment at CERN collected a large sample of diffractively produced π −π −π + events. The data contain contributions from light-meson resonances with the quantum numbers of πJ - and aJ -like states. We performed a partial-wave analysis of this final state for proton and nuclear targets. We consistently observe a π-like signal with J P C = 0−+ in the f2(1270)πD wave. The signal appears to be incompatible with the established π(1800) resonance, which we observe in the decays into (ππ)SπS, f0(980)πS and f0(1500)πS waves.

The primary goal of the GlueX experiment at Jefferson Lab is to map the spectrum of light hybrid mesons. GlueX, which has a linearly polarized photon beam and a large acceptance for both charged and neutral particles, has access to both the neutral, γp → ηπ0 p, and charged, γp → ηπ−∆++, final states. These proceedings will discuss the amplitude analysis of ηπ channels at GlueX with a focus on the study of the production of the a2(1320) meson as function of Mandelstam t.

We discuss the πη(‘) production in the double Regge model. We also identify the dominant exchanges necessary to describe the πη(‘) system for energies above the resonance region. The model explains the forward-backward asymmetry observed in this reaction by associating it with the exotic P−wave, which in turn is related to the production of the putative π1 hybrid meson. We also discuss the π +π − production through two complementary mechanisms - direct resonance production (with subsequent π +π − decay) and the Deck mechanism. The interference of the Deck and direct production explains the di-pion mass distribution for invariant masses below 2 GeV. Model predictions are compatible with the qq¯ nature of the lightest P− and D−wave resonances, whereas they hint towards substantial molecular or tetraquark component of the f0(980).

Recent beauty baryon physics results from the CMS collaboration, obtained using the proton-proton collision data collected at √ s = 13 TeV, are discussed. Observation of the Λ 0 b → J/ψΛφ decay and measurement of its branching fraction, relative to the Λ 0 b → ψ(2S)Λ decay, is reported. The excited baryon states Λb(5912)0 , Λb(5920)0 , Λb(6146)0 , and Λb(6152)0 are confirmed and their masses are measured. Observation of a new excited beauty strange baryon, labeled as Ξb(6100)∗−, is presented.

Impressive progress achieved in the past decade in experimental studies of exclusive meson photoproduction off protons and global multichannel amplitude analyses has resulted in the discovery of several long-awaited new nucleon resonances, with a decisive impact from the results of KΛ and KΣ photoproduction measured with the CLAS detector at Jefferson Lab. Further extension of these efforts towards combined studies of exclusive meson photo- and electroproduction data off protons will be presented. A new excited state of the nucleon, the N 0 (1720)3/2 +, discovered from combined analyses of π +π −p photo- and electroproduction data, in addition to new resonances discovered in photo- and hadroproduction data, demonstrate the promising prospects of this new research avenue for the discovery of additional new resonances.

We investigate the Roper-like singly heavy baryons such as Λc(2765) and Ξc(2967) in a chiral model. Based on chiral symmetry of diquarks inside the baryons, we propose that the Roper-like baryons are mostly pentaquark states (Qqqqq¯ ) while the corresponding ground-state ones Λc(2286) and Ξc(2470) are three-quark states (Qqq). Besides, the mass spectrum of negative-parity Λc and Ξc which are heavy quark spin-singlet is predicted by the linear representation of chiral symmetry. We also derive a sum rule of the heavy baryon masses and an extended Goldberger-Treiman relation. In addition to them, we demonstrate the parity-partner structure of the Λc’s and Ξc’s by showing mass degeneracies of them at the chiral restoration point. We expect that the present investigation leads to a better understanding of the diquarks inside hadrons from the viewpoint of chiral symmetry.

The HADES experiment investigates the nuclear matter and the properties of baryonic resonances. As part of the FAIR Phase-0 program, HADES is being upgraded to enable a wide range of experiments, including investigating electromagnetic decays of hyperons produced in proton-induced reactions. Feasibility studies show that the newly installed forward detectors are crucial for hyperon reconstruction. The detector upgrade and feasibility studies in preparation for the upcoming beamtimes are presented.

Measurements of the cross sections are conducted for coherent photoproduction of the neutral pion and eta meson on the d, gamma deutron to pi0 eta deutron, at the incident energy in the range of the reaction threshold to 1.15 GeV. A rapidly increasing trend below 1 GeV is observed in the total cross section. The data are effectively reproduced by theoretical calculations incorporating the meson-deutron final-state interactions. However, the measured deutron angular distribution d sigma/d Omega_d in the center-of-mass frame (gamma d) is rather flat, and it differs significantly from the strong backward-peaking behavior expected in the kinematics of d formation after pi⁰ eta photoproduction on an initial bound nucleon. In addition, the d sigma/dM_{eta d} differential cross section exhibits a prominent enhancement near the eta d threshold, while d sigma/dM_{pi d} exhibits an enhancement near the known pi d resonance with I=1 and J^P=2⁺. From these observations, we have concluded that two reaction sequences occur; gamma d to pi⁰ D₀₁ to pi⁰ eta d and eta D₁₂ to pi⁰ eta d, where D_IJ denotes a state with a baryon number of 2, an isospin of I, and a spin of J. The enhancement corresponding to D₀₁ is expected to be a theoretically predicted eta NN bound state with I=0 and J^P=1^- or a virtual state of eta d. It is found that attraction between eta d is certainly very strong.

The reaction γp → pπ 0π 0 was analyzed using data of the CBELSA/TAPS experiment where linearly polarized photons impinged on a transversely polarized butanol target. Single and double polarization observables were extracted. Within the BnGa-PWA resonance parameters were determined. N∗ and ∆∗ resonances demonstrated systematic differences in their decay branching ratios via excited hadrons which hint at the internal structure of these states.

In this talk we show that the two-step sequential one pion production mechanism, np(I = 0) → π −pp, followed by the fusion reaction pp → π +d, can explain the narrow peak identified with a “d ∗ (2380)” dibaryon in the np → π +π −d reaction with π +π − in I = 0. We demonstrate that the second step pp → π +d is driven by a triangle singularity that determines the position of the peak of the reaction and the large strength of the cross section. The combined cross section of these two mechanisms produce a narrow peak with the position, width and strength compatible with the experimental observation within the approximations done. This novel interpretation of the peak without invoking a dibaryon explains why the peak is not observed in other reactions where it has been searched for.

We present a lattice calculation of the leading corrections to the masses of nucleons and ∆ resonances. These are obtained in QCD+QED at 1st order in the Isospin Breaking parameters αEM, the electromagnetic coupling, and ( ˆmd − mˆ u)/ΛQCD, coming from the mass difference between u and d quarks

The experimental information and theoretical predictions of d ∗ (2380) are briefly introduced. The salient features of the chiral SU(3) quark model are presented, and the results of d ∗(2380) from traditional calculation in this model are shown and discussed. The problems in such quark model calculations are pointed out, and a revised quark model investigation of d ∗(2380) is given. It is shown that the d ∗ (2380) has not yet been fully understood in quark model.

 The strange quark hadrons sit at an important crossroads between the light and heavy quark hadrons, but their spectrum is comparatively poorly known. The KLF experiment was recently approved to run in Hall D of Jefferson Lab, and will use an intense secondary beam of K_L mesons with the existing GlueX spectrometer to collect data several orders of magnitude larger than existing dataset. In this talk, I will discuss the expected physics reach of this experiment and the status of its preparations  

The Born-Oppenheimer approximation provides a description of heavy-quark mesons firmly based on quenched Lattice QCD. The diabatic framework extends this description through the incorporation of unquenched Lattice QCD data on string breaking. This allows for a unified description of conventional quarkonium, made of QQbar, and unconventional quarkoniumlike mesons, containing meson-meson components as well. A successful description of the charmoniumlike and bottomoniumlike spectra comes out.

BESIII experiment is the only electron positron experiment working in the $\tau$-charm energy region in the world now, and on which the largest sample about Charmonium states has been taken.   The Charmonium-like states, which are hadron states beyond the naive quark model are studied with this sample, in the Charmonium plus light hadron, light hadron only and leptonic final states.

If connecting properties of a multiquark hadron with those exhibited by its constituents, QCD sum rules inferred along the routes of traditional wisdom necessarily involve contributions not related at all to and thus not presenting information about multiquarks. Realizing this deficiency, we propose to increase, for the example of tetraquarks, the predictive power of the QCD sum-rule formalism by disposal of all of the unwanted contributions from the very beginning; this move is easily accomplished by subjecting the contributions to our perspicuous selection criterion.

After carefully examining Feynman diagrams corresponding to the $\bar D \Sigma_c$ hadronic molecular state, we propose a possible binding mechanism induced by shared light quarks. We systematically study its corresponding light-quark-exchange interaction using the method of QCD sum rules, and the obtained results suggest that there can be the $\bar D \Sigma_c$ covalent molecule of $I=1/2$. Our QCD sum rule analyses further indicate a model-independent hypothesis: the light-quark-exchange interaction is attractive when the shared light quarks are totally antisymmetric so that obey the Pauli principle.

A novel scenario is proposed for hidden charm pentaquark (Pc)-like structures in Λ 0 b → J/ψpK−. The scenario is based on kinematical singularities arising from double triangle mechanisms. Anomalous threshold cusps due to the singularities are, compared with ordinary P(∗) c D¯(∗) one-loop thresh-old cusp, significantly more singular. It is demonstrated that an interference among the double triangle mechanisms and other common mechanisms generates peaks very similar to the Pc(4312)+, Pc(4380)+, and Pc(4457)+ peak structures. While hadron molecules and compact pentaquarks have been common models to explain the Pc states, the present model is a completely different one. The present model includes only one pentaquark state Pc(4440)+. However, we find that the Pc(4440)+ width and strength are significantly smaller than those from the LHCb analysis. The P + c signals are searched for in J/ψ photoproduction but not found. A search was also made in Λ 0 b → J/ψpπ− data, finding only a possible P c(4440)+-like signal. The present model is consistent with the experimental situation

In order to understand the nature of the XYZ particles, theoretical predictions of the various XYZ decay modes are essential. In this work, we focus on the semi-inclusive decay of heavy quarkonium hybrids into traditional quarkonium in the Born-Oppenheimer EFT (BOEFT) framework. We find that our numerical results of the decay rates are different from the previous studies. We also develop a systematic framework in which the theoretical uncertainty can be systematically improved.

The a0(980) meson has been considered a tetraquark candidate for over 40 years, but its actual quark content remains in question. The ALICE Collaboration has carried out measurements of K0 SK ± interactions with pp collisions at √ s = 7 TeV and Pb-Pb collisions at √ sNN = 2.76 TeV to study the a0(980) using the method of two-particle femtoscopy. The a0(980) provides the final-state interaction between the kaons in the pair that is used in the femtoscopic analysis of these collisions. The measured femtoscopic source parameters are compared with source parameters extracted in identical-kaon measurements obtained in the same colliding systems. Using a simple geometric argument, our results are found to be compatible with the interpretation of the a0(980) having a tetraquark structure instead of that of a diquark.

We present a recent investigation on the production of P_cs (4459) in the K⁻ p → J/ψΛ reaction, using both the effective Lagrangian and Regge approaches. We assume six different spin and parity assignments, i.e., 1/2^± , 3/2^± and 5/2^± to the newly found P_cs. The total and differential cross sections for the K⁻ p → J/ψΛ reaction are calculated. We examine the dependence of the results on the different assignments of J^P for P_cs.

In this talk we discuss the formation of exotic hadrons with hidden charm arising from three-body interactions. To be more specific, in the strangeness sector, we predict the existence of a mesonic state, $K^*(4307)$, which is dynamically generated from the three-body interactions of the $KD\bar D^*$ system, has a mass around 4307 MeV and quantum numbers $I(J^P) = 1/2 (1^-)$. In the baryonic sector, we predict the existence of $N^*$ states, which are generated from the three-body interactions of the $ND\bar D^*$ system, with masses around 4400∼4600 MeV, widths of 2 ∼20 MeV and positive parity.

The LHCb di-J/ψ spectrum is studied within the framework of effective field theory with four coupled channels {J/ψJ/ψ, J/ψψ(2S), J/ψψ(3770), ψ(2S)ψ(2S)}, in order to unveil possible underlying fully-charmed tetraquark states. The partial-wave analysis is performed properly, and the unitarity of the scattering amplitudes is restored via Bethe-Salpeter equation under on-shell approximation. Four states are found in the energy region [6.2 GeV, 7.6 GeV]. For the partial wave with quantum numbers 0 ++, a bound state X(6200) and a narrow resonance X(7200) can be dynamically generated, while for the 2 ++ partial wave, two different resonant states, one named X(6900) with a narrow width and the other X(6680) with a broad width, can be found. Our results of the mass and width of X(6900) agree well with the experimental ones given by the LHCb collaboration. Furthermore, our findings shed first light on the determination of the J P C quantum numbers of these states

The X(3872) is one of the most puzzling resonances ever observed. First seen by the Belle Collaboration in 2003, it solicited the effort of a hundred of experimental physicists and dozens of theorists, who nowadays are trying yet to shed light on the nature of this peculiar resonant state. It was seen in several decay modes and different production mechanisms, and confirmed by several experiments, so it is well established, and recently is addressed as the the χc1 (3872). Here we report about a re-discovery of the X(3872) with early Belle II data, and discuss plans for future measurements once the full integrated planned luminosity will be achieved by Belle II.

We discuss our lattice QCD calculations of a number of tetraquark channels with at least one heavy quark where some phenomenological models, already fully constrained by fits to the ordinary meson and baryon spectrum, predict deep binding. We find no evidence of deeply-bound tetraquarks, except in previously established strong-interaction stable $I=0$, $J^P=1^+$, $ud\bar{b}\bar{b}$ and $I=1/2$, $J^P=1^+$ $\ell s\bar{b}\bar{b}$ (where $\ell=u/d$) channels, allowing us to rule out models predicting deep binding. Preliminary results from an updated analysis of doubly-bottom tetraquarks are also presented.

The LHCb collaboration reported recently a charm-strange pentaquark state Pcs(4459) found in the J/ψΛ invariant mass distribution. Using a coupled channel unitary approach combined with the local hidden gauge formalism, we investigate the D¯(∗)Ξ (∗,0) c interactions, together with the J/ψΛ and other coupled channels, with the constraints of the heavy quark spin symmetry. We dynamically reproduce the Pcs(4459) state in the coupled channel interactions, which is a degenerate state of D¯ ∗Ξc and analogous to the Pc(4450) state before. Furthermore, we make more predictions for future experiments.

We discuss the effect of relativistic kinematics on the binding energy of multiquark states. For a given potential, the use of relativistic kinematics lowers the energy by a larger amount for the threshold made of two mesons than for a tetraquark, so that its binding is weakened. Some other issues associated with exotic hadrons are also briefly discussed.

The first observation of the three J/ψ meson production in proton-proton collisions at a center-of-mass energy of 13 TeV in final states with three µ +µ − pairs is reported. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 133 fb−1 . The pp → J/ψ J/ψ J/ψ X process is observed with a significance in excess of five standard deviations. The fiducial cross section for this process is found to be σ(pp → J/ψ J/ψ J/ψ X) = 272+141 −104(stat)±17(syst) fb. The result is compared to theoretical expectations for the production of three J/ψ mesons in single (SPS), double- (DPS), and triple- (TPS) parton scattering processes. Under the most economical assumption of factorization of multiple hard scattering probabilities in terms of SPS cross sections, the measured final state is found to be dominated by DPS and TPS contributions. A value of the associated DPS effective cross section parameter of σeff,DPS = 2.7 +1.4 −1.0 (exp)+1.5 −1.0 (theo) mb, related to the transverse distribution of partons in the proton, is derived.

We have determined Rτ/P ≡ Γ(τ → P ντ [γ])/Γ(P → µνµ[γ]) (P = π, K). Whereas P decays are calculated by using Chiral Perturbation Theory (ChPT), τ decays have been studied with an effective approach where ChPT is enlarged by including the lightest resonances and following the high-energy behavior dictated by QCD. These ratios have allowed us to test the lepton universality and the CKM unitarity and also to search for bounds on non-standard interactions. Our results, δRτ/π = (0.18±0.57)% and δRτ/K = (0.97±0.58)%, are consistent with the previous theoretical determinations, but with much more robust assumptions, yielding a reliable uncertainty.

BESIII reports the first observation of the doubly Cabibbo-Suppressed decay D + → K+π +π −π 0 and the first evidence for D + → K+ω using an e +e − collision data sample corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of-mass energy of 3.773 GeV. The ratio of the branching fractions of D + → K+π +π −π 0 over D + → K−π +π +π 0 is significantly larger than other doubly CabibboSuppressed decays in the charm sector. The CP asymmetry in the separated charge-conjugate branching fractions for D + → K+π +π −π 0 is determined and no evidence of CP violation is found. An independent measurement of D + → K+π +π −π 0 with semileptonic tags is also reported.

Based on the data samples of (1310.6 ± 7.0) × 106 J/ψ events at the center-of-mass energy of √ s = 3.097 GeV and 2.93 fb−1 at √ s = 3.773 GeV, BESIII has searched for baryon number violation (BNV) and lepton number violation (LNV) processes in J/ψ, Σ −, and D decays, respectively. No signal events are observed, and the corresponding upper limits on the branching fraction are determined. The Λ-Λ¯ oscillation is also investigated in J/ψ decays, and the upper limits on the oscillation rate and oscillation parameter are extracted.

We discuss the exclusive production of axial-vector f1(1285) meson via the vector-vector fusion mechanism at energies relevant for the HADES and PANDA experiments at FAIR. Total and differential cross sections are given. The possibility of a measurement by HADES at √ s = 3.46 GeV is presented and discussed. The decay channel f1 → π +π −η(→ π +π −π 0 ) seems particularly promising for this purpose.

Hyperon is an ideal probe to study the QCD in the region of non-perturbative to perturbative. Using 1.31 × 109 J/ψ and 448.1 × 106 ψ(3686) events, the hyperon anti-hyperon pair production are well studied. The hyperon polarization and its decay parameter have been measured in high precision through their quantum entangle system. By comparing the decay parameters in hyperon and anti-hyperon decays, the CP conservation observables has been measured which is important to test the Standard Model and search for New Physics.

The recent results from Belle of the τ − → ντπ −e +e − analysis have incentivated us to make a reanalysis of a former work where the Structure Dependent parts are obtained using Resonance Chiral Theory. Here we rely on the same theory accounting for effects that explicitly break such symmetry. A motivation is the involved W πγ? vertex, utterly relevant in computing τ − → ντπ − radiative corrections.

The LHCb experiment is playing a crucial role in the study of rare and forbidden decays of charm hadrons, which are unique probes for hints of physics beyond the Standard Model. These proceedings present results of the search for semileptonic three-body decays of the form $D_{(s)}^+$ \rightarrow $h^\pm$ \ellp $\ell^{(')\mp}$, where $h^\pm$ is a charged pion or kaon and $\ell^{(')\mp}$ is an electron or a muon. Furthermore, studies of the four-body neutral meson charm decays $D^0 \rightarrow \pi^+ \pi^- \mu^+ \mu^-$ and $D^0 \rightarrow K^+ K^- \mu^+ \mu^-$ are discussed. Prospects for leptonic and semileptonic rare charm decays at LHCb in the future are presented in the end.

Recent results from the proton-proton collision data taken by the ATLAS experiment on the charmonium production and on the B_c⁺ meson production and decays are presented. The measurement of J/ψ meson and ψ(2S) meson differential cross sections is reported. New results on the B_c⁺ meson decays to J/ψ D_s^(*)  final states are included. Both studies are based on pp collision data collected at √s=13  TeV during the LHC Run 2, corresponding to an integrated luminosity of 139 fb^-1.  The measurement of the differential ratios of the B_c⁺and B⁺ mesons production cross sections at √s=8 TeV with an integrated luminosity of 20.3 fb^-1is also discussed.

We study the two-body decay of mesons using the covariant helicity formalism. We find that to explain the ratio of partials wave amplitudes (PWAs) of the decay, the Lagrangian must include derivative interactions in addition to contact interactions. We estimate the ratios of the coupling constants for the vector decays of the axial-vector, pseudovector and pseudotensor meson, and the tensor decays of the pseudotensor mesons by fitting the ratios of the PWAs to the available data and predict the ratios to some new decays.

Recent results of the SND experiment at the VEPP-2000 collider on e +e − annihilation to hadrons below 2 GeV are presented. In particular, we discuss measurements of the e +e − → π +π − and e +e − → nn¯ cross sections. The processes e +e − → π +π −π 0 , K+K−π 0 , ηπ0 γ and 2ηγ were under investigation as well. The preliminary results on the e +e − → ωπ0 → π +π −2π 0 cross section measurement are also presented.

The tree-level measurement of the CKM angle γ is one of the most important tests of CP violation in the Standard Model. Discrepancies between measurements in tree-level decays and decays with loops might provide evidence of physics beyond the Standard Model. Results of the recent analysis of B0 → D0K∗0, B0s →D±s K±π±π∓, B± → D h± and B− → D∗K− decays are presented in this paper. A newcombination of all LHCb measurements is also discussed. The achieved precision of the LHCb result, γ = (67 ± 4)◦, dominates the worldaverage.

For a general H_b→H_c τ ν_τ decay, we analyze the role of theτpolarization vector P^μ in the context of lepton flavor universality violation studies. We use a general phenomenological approach that includes several new physics terms and we make specific evaluations of P^μ fordifferent decays. We show that a P^μ component orthogonal to the plane determined by the final hadron and τ three-momenta is only possiblefor complex Wilson coefficients and it would be associated to a violation of the CP symmetry.

The direct production of the charmonium state χc1 in electron positron annihilation is searched by using e +e − collision data at four centerof-mass energies, 3.5080, 3.5097, 3.5104 and 3.5146 GeV collected with the BESIII detector at the BEPC-II collider. By combining the 4 data samples, the χc1 signal is observed with a significance of 5.1σ. An interference pattern between the signal process of e +e − → χc1 → γJ/ψ → γµ+µ − and the background process of e +e − → γISRJ/ψ → γISRµ +µ − is identified. This is the first observation of a C-even state produced directly in e +e − annihilation. At 68.3% confidence level, the electronic width of χc1 is determined to be Γee = (0.12+0.13 −0.08) eV.

Using e ⁺e ⁻ annihilation data corresponding to a total integrated luminosity of 6.32 fb−1 and 2.93 fb−1 collected at the center-of-mass energies 4.178-4.226 GeV and 3.773 GeV with the BESIII detector, we have performed amplitude analyses of the decays D + s → K⁻ K⁺ π⁺, D + s → K0 Sπ⁺π⁰ , D + s → K0 SK−π⁺π⁺, D + s → K+K−π⁺ π⁰ , D + s → ηπ⁺ π⁺ π⁻, and D⁺ → K0 SK⁺π⁰ . We present the results based on these amplitude analyses where rich structures have been observed. In addition, we also report observations of some new hadronic D + (s) decay modes D + s → K⁰ ρ(770)⁺, D + s → K^∗ (892)⁰π ⁺, D + s → K^∗ (892)⁺π⁰ , and D + (s) → a0(980)+ρ 0 and the determinations of their decay branching fractions which are 5.46±0.84_stat. ±0.44_syst. ×10⁻³ , 2.71±0.72_stat. ±0.30_syst. ×10⁻³ , 0.75±0.24_stat. ±0.06_syst. ×10⁻³ , and 0.21 ± 0.08_stat. ± 0.05_syst.%

We present an overview of four recent measurements of charm decays performed at the LHCb experiment. These include the first observation of the non-zero mass difference between neutral charm-meson eigenstates, the most precise measurements of ∆YKK and ∆Yππ, and timeintegrated ACP of eight two-body charm decays. The precision of the measurements is mainly limited by statistical uncertainty, so further improvement is expected with the upcoming LHC Run 3.

Measurements of CP asymmetries in charmless two-body B-meson decays can provide stringent tests of the Standard Model. In multibody decays, short and long-distance dynamics along with a sizeable effective weak phase in the interference between tree and penguin amplitudes can lead to a rich structure of CP violation as a function of the phase space. We present here the latest studies of CP violation in charmless b-hadron decays, in particular those with baryons in the initial and final states.

In this talk I review the findings of our recent works where we have studied the decay of N ∗ (1895) and the implications of such properties on the photoproduction of light hyperons. I discuss that meson-baryon interactions play an essential role in describing the nature of N ∗ (1895) and report the details of our investigation of its decays to different meson-baryon systems and to final states involving Λ(1405) and a proposed Σ(1400). We find that the width of N ∗ (1895) gets important contributions from the decay to light hyperon resonances. Such an information can be used to look for alternative processes to study N ∗ (1895) in experimental data.

Within the present work, the main points of the talk and paper shall be recapped, which are amongst others the foundations of Moravcsik’s Theorem, the definition of the polarization observables, the extraction of complete sets as well as the implication for experimentalists.

This work presents ideas for the determination of complete experiments using graphs, which are based on a recently published, modified form of Moravcsik’s theorem. The lucid representation of complete experiments in terms of graphs, which is at the heart of the theorem, leads to a fully automated procedure that can determine complete experiments for in principle any reaction, i.e. for any number of amplitudes N . For larger N (i.e. N ≥ 4), the sets determined according to Moravcsik’s theorem turn out to be slightly overcomplete. A new type of directional graph has been proposed recently, which can decrease the length of the complete sets of observables in some of these cases. The presented results are relevant for reactions with larger numbers of spin-amplitudes, which are at the center of interest in forthcoming measurements, such as single-meson electroproduction (N = 6), two-meson photoproduction (N = 8) or vector-meson photoproduction (N = 12).

The weak-binding relation is a useful tool to study the internal structure of hadrons from the observable quantities. We introduce the range correction in the weak-binding relation for the system having a sizable magnitude of the effective range, and show that the applicability of the weak-binding relation can be enlarged by the range correction. Thanks to the low-energy universality, the weak-binding relation can be used to study the structure of shallow bound states in any systems with different length scales. We apply the weak-binding relation to actual systems, including hadrons, hypernuclei, and atoms and show the importance of the range correction.

Particle scattering is a powerful tool to unveil the nature of various subatomic phenomena. The key quantity is the scattering amplitude whose analytic structure carries the information of the quantum states. In this work, we demonstrate our first step attempt to extract the pole configuration of inelastic scatterings using the deep learning method. Among various problems, motivated by the recent new hadron phenomena, we develop a curriculum learning method of deep neural network to analyze coupled channel scattering problems. We show how effectively the method works to extract the pole configuration associated with resonances in the πN scattering.

We perform a quantum calculation of the 1S charmonium mass by simulating the spinless Cornell Hamiltonian on a quantum processor using a variational method. Errors due to a global depolarizing noise channel are corrected with a zero-noise extrapolation method, resulting in good agreement with the known value. We also calculate the 2S mass of charmonium on a noiseless quantum simulator by orthogonalizing with respect to the ground state. This research demonstrates that near-term quantum devices are capable of simulating heavy quark bound states, which are currently under-represented in the literature.

A database is under construction to provide a complete collection of published basic properties of hypernuclei such as Λ binding energies, lifetimes, or excitation energies. From these values, averages with related errors are computed in a systematic way. For each property, the overall experimental situation is depicted in form of an ideogram showing the combined probability density function of the measurements. The database is accessible via a dynamic website at https://hypernuclei.kph.uni-mainz.de with an user interface offering customizable visualizations, selections, or unit conversions. The capabilities of the database are demonstrated for the puzzling and disputed data situation of the hypertriton.

In this work, we discuss a new phenomenological model suited to all SU(3) mesonic two-body final-state interactions up to energies around 2 GeV to replace the standard isobar model. We show that the new model provides a clear indication of the mechanism responsible for the sharp rise observed in the ππ phase around 1 GeV. The phenomenological amplitudes proposed here are suited to any number of resonances, incorporate chiral symmetry at low energies, include coupled channels, and respect unitarity.

In this talk we show our recent results on the decay widths of φ(2170) to final states formed by an anti-Kaon and a Kaonic resonance, in particular, K(1460), K1(1270) and K1(1400), considering a molecular description for φ(2170). Branching fraction ratios are obtained and compared with the recent results found by the BESIII collaboration, finding compatible results.

We report preliminary results from a study of hadronic transitions of the χbJ (nP) states of bottomonium at Belle. The P-wave states are reconstructed in transitions to the Υ(1S) with the emission of an ω meson. The transitions of the n = 2 triplet states provide a unique laboratory in which to study nonrelativistic quantum chromodynamics, as the kinematic threshold for production of an ω and Υ(1S) lies between the J = 0 and J = 1 states. A search for the χbJ (3P) states is also reported.

We present the results on the relativistic six-pion scattering amplitude at low energy, calculated at O(p 4 ) within the framework of the massive O(N) nonlinear sigma model extended to the next-to-leading order in the chiral counting. For N = 3, this approach corresponds to the two(- quark)-flavor Chiral Perturbation Theory. We also present the expressions for the pion mass, pion decay constant and the four-pion amplitude in the case of N (meson) flavors at O(p 4 ).

Hyperons provide a unique avenue to study the strong interaction. Due to their limited lifetime, the hyperon production in e +e − collisions is a new viable way to obtain information to understand the hyperon structure and internal dynamics, and even insight into the nature of the charmonium(-like) states. With the unique data sets obtained by the BESIII experiment, the recent results for the hyperon pair production in e +e − collisions are presented, such as observation of ψ(3686) → Ξ(1530)−Ξ(1530) ¯ +, determination of the Ω − spin, observation of the Ξ hyperon polarization, study of threshold effect in the sector of Ξ hyperon, search for Y (4230/4260) → Ξ −Ξ¯+ and so on.

SPD is an international Collaboration gathering around the Spin Physics Detector at the Nuclotron-based Ion Collider FAcility (NICA), presently under construction at the Joint Institute per Nuclear Research, in Dubna. The project is briefly presented with special focus to the opportunities opened by the collision of high luminosity polarized proton and deuteron beams with total energy up to $\sqrt{s}$=27 GeV. Examples of the foreseen research program are highlighted, in connection with the spin structure of light nuclei, the proton gluon content and the spin dependence of the nucleon-nucleon interaction. The unicity of NICA-SPD makes the future results complementary to the studies that have been or will be performed at other polarized hadron machines in different energy domains.

From a deformed AdS₅ space, we used the string/gauge duality to study the deep inelastic scattering for unpolarized fermions with spin 1/2, considering the large Bjorken x parameter regime. Here, we also took into account an anomalous dimension of an operator which represents fermions at the boundary. From this analysis, we compute the corresponding structure functions, which are dependent on $x$ and on the photon virtuality q. The results achieved are in agreement with the experimental data.

Single quarks moving in the vacuum of confining gauge theories are stopped by a drag force. The holographic description relates the confining scale in the bulk geometry with a range of physical values for the drag force in the vacuum. The vacuum drag force acting on the isolated quark directly manifests quark confinement since it prevents the quark from walking freely in the vacuum. However, analytical expressions for the drag force as a function of the quark velocity were lacking. In the present work, we propose that the vacuum drag force is given by the regularized zero-temperature limit of the corresponding thermal drag force. Within this approach, we obtain the desired analytic expressions in two different holographic models: the quadratic dilaton and the D-instanton. In both cases, we find well-behaved functions belonging to their physical range of values.

Several possible experimental channels have been proposed in the past to access the chiral-odd transversity distribution functions h1. Among these, the measurements of target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive Deep Inelastic Scattering (SIDIS) gave clear evidence that transversity is measurable and sizable in the valence region. A third, independent channel is the measurement of the polarization of Λ hyperons produced in SIDIS off transversely polarized nucleons, where the transverse polarization of the struck quark might be transferred to the final-state hyperon. The COMPASS Collaboration at CERN has measured the transversityinduced polarization of Λ and Λ¯ hyperons produced in SIDIS off transversely polarized protons, found compatible with zero. The results are shown here and discussed in the context of different models and approximations

This work discusses the electromagnetic (EM) pion form factor ($\pi FF$) in a deformed AdS geometry. We consider the conformal dimension of the hadron bulk field defined by the scaling dimension of the $q\,\bar{q}$ operator instead of the twist. We also compute the pion EM radius and compare it with the experimental data, finding a relative error of $2\,\%$.

Inspired by the Direct and Indirect maximal center gauge methods which identify vortices in lattice calculations, and by using connection formalism, we show that under some appropriate gauge transformations, vortices and chains appear in the continuum limit of QCD vacuum.

The kaonic deuterium 2p→1s transition X-ray measurement, a fundamental information needed for a deeper understanding of the Quantum ChromoDynamics (QCD) in the strangeness sector, is still missing. The SIDDHARTA-2 collaboration is now ready to achieve this unprecedented result thanks to the dedicated experimental apparatus that will allow to obtain the values of the kaonic deuterium K-transitions with a precision comparable to the most precise kaonic hydrogen measurement to-date performed by SIDDHARTA in 2009. Both the kaonic hydrogen and kaonic deuterium X-ray spectroscopy measurements of the de-excitation towards the fundamental level are a direct probe on KN interaction at threshold, as opposed to the scattering experiments which need an extrapolation to zero energy. Combining these results through the Deser-Truemann like formula, the isospin-dependent kaon-nucleon scattering lengths can be obtained in a model-independent way. The SIDDHARTA-2 setup is presently installed at the DAΦNE (Double Annular Φ Factory for Nice Experiments) collider of Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali di Frascati and it is ready to perform the challening kaonic deuterium measurement. This
paper provides an overview on the SIDDHARTA-2 experimental apparatus and a preliminary result of the kaonic helium run, preparatory for the SIDDHARTA-2 data taking campaign, is also presented.

We study good, bad and not-even-bad diquarks on the lattice in a gauge-invariant formalism in full QCD. We establish their spectral masses with short extrapolations to the physical point, observing agreement with phenomenological expectations. We find that only the good diquark has attractive quark-quark spatial correlations, with spherical shape and size of about 0.6 fm. Our results provide quantitative support for modelling the low-lying baryon spectrum using good light diquark effective degrees of freedom.

We report recent results of Nucleon Electromagnetic Form Factors at the BESIII experiment. The BESIII detector is installed at the BEPCII electron-positron collider in Beijing (PRC) with a center-of-mass energy range between between 2.0 and 4.9 GeV. The Nucleon Electromagnetic Form Factors has been measured in BESIII both via direct e+e− annihilation and initial-state-radiation technique.

The properties of quarkonia are discussed in the framework of the nonrelativistic potential approach based on the instanton-induced interactions from the instanton vacuum.  we have obtained the spectrum of charmonia and discuss the results. We also examine the instanton effects on the color-octet heavy-quark potential.

Focusing on hadron scattering at large partonic momentum fractions x, we compare nonperturbative QCD predictions for the asymptotic behavior of DIS structure functions and parton distribution functions (PDFs) to the x and Q dependence of phenomenological PDFs. In the CT18 NNLO global QCD analysis, higher-order radiative contributions and functional mimicry of PDF parametrizations result in about one unit of uncertainty in the effective powers of (1 − x) falloff of nucleon PDFs. Similar uncertainties are present in the case of the pion PDF, an object of growing interest in phenomenology.

The spectrum of glueballs with quantum numbers J^PC = 0^±+, 2^±+, 3^±+, 4^±+ is calculated in quenched quantum chromodynamics (QCD) from bound state equations. The input is taken from a parameter-free calculation of two- and three-point functions. Our results agree well with lattice results where available and contain also some additional states. For the scalar glueball, we present first results for the effects of additional diagrams which turn out to be strongly suppressed.

We study the influence of non-valence quark-pair contributions in weak transition form factors of heavy-light mesons. Form factors are first calculated for spacelike momentum transfers in a reference frame where such contributions are suppressed. Analytic continuation to the timelike region and a comparison with the direct decay calculation, done with pure valence degrees of freedom, provides an estimate of the role that quark-pair contributions may play. We use the point form of relativistic quantum mechanics, which is particularly useful when treating heavy-light systems.

Heavy-flavour production is an active and highly interesting field of research. Since charm and beauty quarks are predominantly produced in the hard scattering process of colliding nuclei, they serve as unique probes to study the quark-gluon plasma in \PbPb{} collisions. In addition, recent investigations of hadronisation mechanisms have revealed interesting and unexpected features when comparing measurements in \ee{} and in hadronic collisions as in \pp{}, \pPb{} and \PbPb{}. This article summarises the latest results of charm production measured by the ALICE Collaboration. For the first time, \Scnullpp{} and \Onull{} were measured in hadronic collisions and production measurements of the \Lc{} and \Xcnull{} are now included in the computation of the charm production cross section.

In the present work, we describe a model for the pion based on an analytic expression for the Bethe-Salpeter (BSA) amplitude, combined with some ingredients from Lattice QCD calculations. The running quark mass function M(_p²), used here, reproduces well the results of Lattice QCD calculations. The analytical form of the running quark mass function contains a single time-like pole, which implies in time-like poles of the dressed quark propagator. Such a form allows to build the weight functions, G_i(γ, z), for the Nakanishi integral representation of each scalar function, χ_i(k, p), appearing in the decomposition of the Bethe-Salpeter amplitude in terms of Dirac operators. Such scalar amplitudes can also be used to obtain the pion valence light-front wave function.

A classical model of a stable particle of finite size is studied. The model parameters can be chosen such that the described particle has the mass and radius of a proton. Using the energy-momentum tensor (EMT), we show how the presence of long-range forces alters some notions taken for granted in short-range systems. We focus our attention on the D-term form factor. The important conclusion is that a more careful definition of the D-term may be required when long-range forces are present.

We demonstrate that the ’t Hooft equation and the light-front holographic Schrodinger equation are complementary to each other in governing ¨ the longitudinal and the transverse dynamics of color confinement in mesons (quark-antiquark) and baryons (quark-diquark). Together, they describe remarkably well the spectroscopic data for the light-light, heavy-light and heavy-heavy hadrons. In all hadrons, the transverse dynamics of confinement is controlled by the universal emerging hadronic scale of the light-front holography, κ ∼ 0.5 GeV, which, in heavy-heavy hadrons, coincides with the ’t Hooft coupling that governs the longitudinal confinement. This reflects the restoration of the rotational symmetry in the non-relativistic limit.

We present preliminary results on the longitudinal and transverse form factors of the quark-gluon vertex as functions of the incoming and outgoing quark momenta and an angle θ = 2π/3 between them. The expressions for these form factors were previously derived from Slavnov-Taylor identities, gauge covariance and multiplicative renormalizability that firmly constrain the fermion-boson vertex.

We discuss the production mechanism of fully charm tetraquark, observed last year by the LHCb at M = 6.9 GeV in the J/ψJ/ψ channel. Both single parton scattering (SPS) and double parton scattering (DPS) mechanisms are considered. We calculate the distribution in the invariant mass of the four-quark system, M4c, for SPS and DPS production of ccc¯c¯ in the kt-factorization approach. We present transverse momentum distribution in pt,4c for ccc¯ c¯ system in a mass window around tetraquark mass. The calculation of the SPS g ∗ g ∗ → T4c(6900) fusion mechanism is performed in the kT -factorization approach assuming different spin scenarios (0 + and 0 −).

The proton has been studied in a fully dynamical three-body model on the light-front. The model is based on the concept of a strongly interacting diquark, either bound or virtual, which is generated from a zero-range interaction between the two active quarks. The obtained results for the Dirac electromagnetic form factor and also the density in the Ioffe-time space are shown and discussed. Additionally, we present results for the parton distribution function of the proton.

The light-quark mass dependence of the nucleon axial isovector charge (g_A) has been analysed up to NNLO, O(p⁴), in relativistic chiral perturbation theory using extended-on-mass-shell renormalization, without and with explicit Delta(1232) degrees of freedom. In the Delta-less case at this order, the g_A(M_pi)  dependence of lattice QCD simulations cannot be reproduced using low energy constants extracted from pion-nucleon phenomenology. A good description of these LQCD data is only accomplished in the theory with Delta. From this fit we obtain g_A(M_pi^phys)=1.260(12) close to the experimental results and d₁₆= -0.88(88) GeV^-2 in agreement with pi N-> pi pi N. The sizeable errors are of theoretical origin, reflecting the difference between O(p³) and O(p⁴) at large M_pi.

In this contribution we present the main results of the investigation about double parton scattering (DPS) in quasi-real photon proton interactions. We show the first evaluation of the DPS cross-section at leading-order for the four-jet photo-production observed at HERA. To this aim the $\gamma-p$ effective cross section has been computed for the first time. One of the main outcomes of this analysis is that the DPS contribution is not negligible and potentially measurable. Furthermore, possible future data could be used to get new information on the transverse proton structure not accessible in other processes.

We explain a gluon transversity, transverse-momentum-dependent parton distribution functions (TMDs), and parton distribution functions (PDFs) for spin-1 hadrons. The gluon transversity exists in hadrons with spin more than or equal to one, and it does not exist in the spin-1/2 nucleons. Since there is no direct contribution from the nucleons, it is an appropriate quantity to probe an exotic component in the spin-1 deuteron beyond a simple bound system of the nucleons. We show how the gluon transversity can be measured at hadron accelerator facilities by the Drell-Yan process in addition to lepton-accelerator experiments. Next, possible TMDs are explained for the spin-1 hadrons at the twists 3 and 4 in addition to twist-2 ones by considering tensor polarizations. We found that 30 TMDs exist in the tensor-polarized spin-1 hadron at the twists 3 and 4 in addition to 10 TMDs at the twist 2. There are 3 collinear PDFs at the twists 3 and 4. We also indicate that the corresponding TMD fragmentation functions exist at the twists 3 and 4. Due to the time-reversal invariance in the collinear PDFs, there are new sum rules on the time-reversal odd TMDs. In addition, we obtained a useful twist-2 relation, a sum rule, and relations with multiparton distribution functions by using the operator product expansion and the equation of motion for quarks. These findings are valuable for experimental investigations on polarized deuteron structure functions in 2020's and 2030's at world accelerator facilities.

In this talk, we present an extension to the matching procedure proposed by Brodsky and de Teramond to obtain the two-body wave functions in the light-front formalism for holographic models. We consider different static dilaton fields and AdS-like geometric deformations.

Describing hadronic structure is one of the most intriguing problems in physics. In this respect, generalized parton distributions (GPDs) constitute an outstanding tool, allowing to draw “three dimensional pictures” of hadron’s inside. Starting from contemporary models for pion’s GPDs fulfilling all constraints imposed by QCD, we compute Compton form factors of pions subjected to deeply virtual Compton scattering. We show CFF’s behaviour to be gluon-dominated at EIC’s kinematics. Finally we evaluate lepton-beam-spin asymmetries in the Sullivan process, demonstrating the existence of such and thus triggering optimism about the possibility of probing pion’s 3D structure at electron-ion colliders.

We discuss the coupled dynamics of the ghost dressing function and the ghost-gluon vertex through the Schwinger-Dyson equations that they satisfy. In order to close the system of equations, we combine recent lattice data for the gluon propagator and an approximate STI-derived Ansatz for the general kinematics three-gluon vertex. The numerical solution of the resulting coupled system exhibits excellent agreement to lattice data, for both the ghost dressing function and the ghost-gluon vertex, and allows the determination of the coupling constant. Next, in the soft gluon limit the full three-gluon vertex appearing in the ghost-gluon equation reduces to a special projection that is tightly constrained by lattice simulations. Specializing the ghost-gluon Schwinger-Dyson equation to this limit provides a nontrivial consistency check on the approximations employed for the three-gluon interaction and shows that the latter has an important quantitative effect on the ghost-gluon vertex. Finally, our results stress the importance of eliminating artifacts when confronting lattice data with continuum predictions.

For hadron collisions, transverse-momentum-dependent parton distribution functions (TMD PDFs) are important quantities to connect the- oretic calculations and experimental cross sections. And recently, basis light-front quantization (BLFQ) has become a powerful tool to investigate the structures of the bound state. We present the first calculations within the BLFQ framework for the leading twist quark TMDs under a trivial assumption of the gauge link. We compare our calculations with previous calculations via the PDF limit and evolve our results of the unpolarized TMDs.

The collinear factorization theorem, combined with finite-order calculations in perturbative QCD, provides a powerful framework to obtain predictions for many collider observables. However, for observables which involve multiple energy scales, transverse degrees of freedom cannot be neglected, and finite-order perturbative calculations have to be combined with resummed calculations to all orders in the QCD running coupling in order to obtain reliable theoretical predictions, capable of describing experimental measurements. This is traditionally done either by analytic resummation methods or by parton shower (PS) Monte Carlo (MC) methods. In this talk we present the Parton Branching (PB) MC method to obtain QCD collider predictions based on Transverse Momentum Dependent (TMD) factorization. The PB provides evolution equations for TMD Parton Distribution Functions (PDFs) which, upon fitting TMD PDFs to experimental data, can be used in TMD MC event generators. We present the basic concepts of the method and illustrate its applications to collider measurements focusing on Drell-Yan (DY) lepton-pair production in different kinematic ranges, from fixed-target to LHC energies. We discuss the latest developments of the method concentrating especially on the matching of next-to-leading-order (NLO) TMD evolution with MC-at-NLO calculations of NLO matrix elements.

We present our recent calculation of the gravitational form factors (GFFs) of proton using the light-front quark-diquark model constructed by the soft-wall AdS/QCD. We extract the four quark GFFs by calculating the matrix elements of the symmetric energy momentum tensor. Using the D-term we calculate the pressure and shear distributions of quarks inside the proton in the impact parameter space. The GFFs, A(Q²) and B(Q²) are found to be consistent with the lattice QCD, while the qualitative behavior of the D-term form factor is in agreement with the extracted data from the deeply virtual Compton scattering (DVCS) experiments at JLab, the lattice QCD, and the predictions of different phenomenological models.

Momentum and spatial distributions of quarks and gluons inside hadrons are typically encoded in the so-called generalized parton distributions (GPDs). GPDs are multi-dimensional quantities that are very challenging to extract, both experimentally and within lattice QCD. We present the first lattice results on the x-dependence of isovector unpolarized, helicity and transversity GPDs of the proton, obtained from lattice QCD using an ensemble of Nf = 2 + 1 + 1 maximally twisted mass fermions, with pion mass Mπ = 260 MeV and lattice spacing a ' 0.093 fm. Our calculations use the quasi-distribution formalism and the final distributions are presented in the MS scheme at a renormalization scale of 2 GeV.

We calculate the binding energy and structure of the positronium system in a light-front nonperturbative approach. The input interaction is from Quantum Electrodynamics first principles and one dynamical photon is explicitly included in the basis. We obtain the low-lying mass spectrum, which is found to be consistent with that from nonrelativistic quantum mechanics. Various excitation modes of the low-lying states can be identified from the associated wave functions. The photon distribution in the longitudinal direction is calculated for the low-lying positronium states.

The extraction of elastic form factors for mesons in the context of the contact interaction model is revisited in this manuscript. The dressed masses of quarks and mesons are determined through the gap and Bethe-Salpeter equations. The generic elastic scattering process $M\gamma \to M$ is studied for the meson $M$ formed of two differently flavored quarks. The charge radii of scalar, pseudoscalar, vector and axial-vector mesons are also extracted by virtue of explicit calculation of the meson elastic form factors.

We describe an algebraic approach to address aspects of the structure of pseudo-scalar mesons through their corresponding generalized parton distributions, from which parton distribution functions and electromagnetic form factors can be derived. A direct relation between such distributions and the so-called parton distribution amplitudes can be established since the generalized parton distributions are obtained from the overlap of light-front wave functions.

We present exploratory studies of the proton content via unpolarized and polarized transverse-momentum-dependent gluon distributions in the proton at leading twist. We make use of an enhanced spectator-model approach to encode in our densities both small- and moderate-$x$ effects. These studies are relevant to the investigation of the inner structure of hadrons via tomographic analyses at new-generation colliding machines.

Inclusive as well as exclusive emissions in forward and central directions of rapidity are widely recognized as excellent channels to access the proton structure at small x. In this regime, to describe nucleons structure, it is necessary to use kT -unintegrated distributions. In particular, at large transverse momenta, the x-evolution of the so-called unintegrated gluon distribution is driven by the Balitsky-Fadin-Kuraev-Lipatov equation, within the framework of the high-energy factorization (HEF). Recent analyses on the diffractive electroproduction of ρ mesons have corroborated the underlying assumption that the small-size dipole scattering mechanism is at work, thus validating the use of the HEF formalism. Nonetheless, a significant sensitivity of polarized cross sections to intermediate values of the meson transverse momenta, where, in the case of inclusive emissions, a description at the hand of the transverse momentum dependent (TMD) factorization starts to be the most appropriate framework, has been observed. In this work, we will review the formal description of the UGD within the BFKL approach and present some UGD models that have been proposed, then we will describe the state of the art of some recent phenomenological analyses.

We obtain the light-front wave functions (LFWFs) of the nucleon in the leading Fock sector representation using basis light-front quantization (BLFQ) approach. We adopt a light-front effective Hamiltonian, which includes a three-dimensional confining potential and a one-gluon exchange interaction with fixed coupling, and solve for it mass eigenstates. We then employ the LFWFs to compute the axial form factor and the transverse charge and magnetization densities for the nucleon. The axial form factor is found to be consistent with the experimental data. The charge and magnetization densities agree qualitatively with the phenomenological fits.

The three-gluon vertex is a fundamental ingredient of the intricate QCD dynamics, being inextricably connected to key nonperturbative phenomena, such as the emergence of a mass scale in the gauge sector of the theory. In this presentation, we review the main theoretical properties of the three-gluon vertex in the Landau gauge, obtained from the fruitful synergy between functional methods and lattice simulations. We pay particular attention to the manifestation and origin of the infrared suppression of its main form factors and the associated zero crossing. In addition, we discuss certain characteristic phenomenological applications that require this special vertex as input.

 

The wide-angle photo- and electroproduction of pions is investigated within the handbag mechanism in which the γ (∗)N → πN0 amplitudes factorize into subprocess amplitudes,γ (∗) q → πq0 , and form factors representing 1/x-moments of generalized parton distributions (GPDs). The subprocess is calculated to twist-3 accuracy taking into account both the 2- and 3-body Fock components of the pion. The cross-sections are compared to experiment and spin-effects are discussed.

In this talk, we present the analysis of a deeply virtual Compton scattering process off 4 He. This study is done within the impulse approximation approach including state-of-the-art models for the nucleonic and nuclear ingredients. A glimpse on the comparison between our results and the experimental data coming form Jefferson Lab is also given. The last part of this work is devoted to the description of the new Monte Carlo event generator based on the models presented in the main part of the talk. First results from the simulations performed at the kinematic conditions foreseen at the Electron Ion Collider are discussed demonstrating that there is a wide enough kinematical range to reach the tomography of 4 He and understand other possible aspects of the elusive nuclear parton dynamics.

A formula to calculate the quantum fluctuations of energy in small subsystems of a hot and relativistic gas is derived. We find an increase in fluctuations for subsystems of small sizes, but we agrees with the energy fluctuations in the canonical ensemble if the size is large enough. Not only one can use our expression to find the limit of the concepts of energy density or fluid element in connection to relativistic heavy-ion collisions, but also in other areas of physics where one studies matter with high temperature and velocity.

Studies of jet fragmentation in heavy-ion collisions can provide information about the mechanism of jet quenching inside the hot and dense QCD matter created in these collisions. These proceedings present results from measurements of charged particle yields within and around the jets in dijet, gamma+jet and Z+jet systems measured in $5.02$~TeV Pb+Pb and $pp$ collisions using the ATLAS detector at the LHC.

The main goal of the ALICE experiment is to study the physics of strongly interacting matter, focusing on the properties of the quark-gluon plasma (QGP). The relative production of strange hadrons with respect to non-strange hadrons in heavy-ion collisions was historically considered as one of the signatures of QGP formation. However, the latest results in proton-proton (pp) and proton-lead (p-Pb) collisions have revealed an increasing trend in the yield ratio of strange hadrons to pions with the charged-particle multiplicity in the event, showing a smooth evolution across different collision systems and energies.

We present the new studies which are performed with the aim of better understanding the production mechanisms for strange particles and hence the strangeness enhancement phenomenon in small collision systems. In one of the recent studies, the very forward energy transported by beam remnants (spectators) and detected by the Zero Degree Calorimeters (ZDC) is used to classify events. The contribution of the effective energy and the particle multiplicity on strangeness production is studied using a multi-differential approach in order to disentangle initial and final state effects. In the second study, the origin of strangeness enhancement with multiplicity in pp has been further investigated by separating the contribution of soft and hard processes, such as jets, to strange hadron production. Techniques involving full jet reconstruction or two-particle correlations have been exploited. The results indicate that the increased relative strangeness production emerges from the growth of the underlying event, being disconnected from initial state properties, and suggest that soft (out-of-jets) processes are the dominant contribution to strange hadron production.

In this proceedings contribution I review recent progress concerning the suppression of bottomonium production in the quark-gluon plasma.  Making use of open quantum system methods applied to potential non-relativistic quantum chromodynamics one can show that the dynamics of heavy-quarkonium bound states satisfying the scale hierarchy 1/a₀ » πT ∼ m_D  » E obey a Lindblad equation whose solution provides the quantum evolution of the heavy-quarkonium reduced density matrix.  To solve the resulting Lindblad equation we use a quantum trajectories algorithm which allows one to include all possible angular momentum states of the quark-antiquark probe in a scalable manner.  We solve the Lindblad equation using a tuned 3+1D dissipative hydrodynamics code for the background temperature evolution.  We then consider a large number of Monte-Carlo sampled bottomonium trajectories embedded in this background.  This allows us to extract the centrality- and p_T-dependence of the nuclear suppression factor R_AA[Υ] and elliptic flow v₂[Υ].  We find good agreement between our model predictions and available √ s_NN = 5.02 TeV = 5.02 TeV Pb-Pb collision experimental data from the ALICE, ATLAS, and CMS collaborations.

We review recent work on thermal resonances and their connection with chiral symmetry and U(1)_A restoration within the QCD phase diagram. In particular, the ƒ₀ (500) and K∗ 0 (700) states generated from ππ and πK scattering within Unitarized Chiral Perturbation Theory (ChPT) at finite temperature allow one to describe scalar susceptibilities, which combined with Ward Identities yield interesting conclusions regarding the interplay between chiral and U(1)_A restoration, key to understand the nature of the transition.

In the last decade, heavy-ion based experiments (HypHI, STAR and ALICEi ) announced surprisingly short lifetime for 3 ΛH mesonic weak decay (MWD), which is difficult to interpret given the fact that 3 ΛH is a very loosely bound system. It will be very interesting to study this issue with a different experimental approach. We propose a direct measurement for 3 ΛH hypernucleus MWD lifetime with ∼10% precision as J-PARC E73 experiment; 4 ΛH hypernucleus lifetime will also be measured as a feasibility test for our experimental approach. In this proceeding, we will introduce the experimental method and the current status of E73 experiment.

In this contribution, we summarize our recent studies on the chiral invariant mass and the chiral condensates in neutron star matter. We construct a unified equations of state assuming the crossover phase transition from hadronic matter described by a parity doublet model to quark matter by an Nambu--Jona-Lasinio type quark model. We first show that the chiral invariant mass is constrained to be $600\,\mbox{MeV}\, \lesssim\, m_0 \,\lesssim \, 900\,\mbox{MeV}$ from recent observations of neutron stars. We then determine the density dependence of the chiral condensate in the crossover description, and show that the chiral condensates are actually smoothly connected from the hadronic matter where the change is driven by the positive chiral scalar charge in a nucleon, to the quark matter where the change is by the modification of the quark Dirac sea, reflecting the hadron-quark crossover. 

A machine learning model has been developed to search events of production and decay of a hypertriton in nuclear emulsion data, which is used for measuring the binding energy of the hypertriton at the best precision. The developed model employs an established technique for object detection and is trained with surrogate images generated by Monte Carlo simulations and image transfer techniques. The first hypertriton event has already been detected with the developed method only with 10⁻⁴ of the total emulsion data. It implies that a sufficient number of hypertriton events will soon be detected for the precise measurement of the hypertriton binding energy.

The non-equilibrium properties of a quark-gluon plasma (QGP) have been a topic of intensive research. In this contribution, we explore the nature of heavy quarkonia immersed in a QGP with bulk viscosity.  We incorporate the bulk viscous effect through the deformation of the distribution functions of thermal quarks and gluons, with which the color dielectric permittivity can be computed.  We use the color dielectric permittivity to compute the heavy quark potential inside a bulk viscous plasma, and solve the Schr\"odinger equation using the potential to obtain the physical properties such as binding energies and decay widths. We discuss the effect of the bulk viscous correction on the quarkonium properties and the melting temperatures.

The correlation functions of pΞ − and ΛΛ pairs from high-energy pp collisions are investigated in the coupled-channel formalism. The NΞΛΛ coupled-channel potentials obtained in the lattice QCD calculation at almost physical quark masses are employed. The pΞ − correlation function shows the large enhancement from the pure Coulomb case, while the ΛΛ correlation function shows the moderate enhancement from the pure quantum statistics case. This agreement indicates that both the NΞ and ΛΛ interactions are moderately attractive without having quasibound or bound state.

The hierarchy of scales of heavy quarks and their bound states in a quark gluon plasma makes the system ideally suited for the use of effective field theories and the formalism of open quantum systems.  We utilize these tools to perform a first principles treatment of these heavy particles in medium and analyze the regimes in which the dynamics take the form of a Langevin equation in which the medium and the heavy particle interact via random "kicks" altering the particle's momentum.

We study the confinement/deconfinement phase diagram within a five-dimensional fully anisotropic holographic model supported by Einsteindilaton-three-Maxwell action. One of the Maxwell fields provides the chemical potential, the second Maxwell field represents real spacial anisotropy of the QGP produced in heavy-ion collisions and the third Maxwell field is related to an external magnetic field. Influence of the so-called primary anisotropy due to the non-centrality of the heavy-ion collision and secondary anisotropy originating from the external magnetic field on the phase diagram is considered. Based on recent work [1,2].

Quarkonium suppression in relativistic heavy ion collisions has been studied experimentally for decades to probe the properties of the quark-gluon plasma. For this purpose, complete theoretical understanding of the time evolution of quarkonium inside the quark-gluon plasma is needed but challenging. Here I review recent progress in applying the open quantum system framework to describe the real-time dynamics of quarkonium, with a focus on the chromoelectric field correlators of the plasma that control the dynamics.

In recent years, a momentum-independent symmetry preserving vector-vector contact interaction has been used to provide exploratory studies in QCD. It helps calculate different static and dynamic observables of all mesons and baryons. In this work, we revisit how the quark gap equation is affected by changing the number of quark colors and/or flavors, or by placing quarks in a thermal bath in the presence of an external magnetic field. In particular, we describe how the phenomenon of magnetic catalysis and its inverse can be studied.

We present Λ separation energies for light hypernuclei based on chiral hyperon-nucleon interactions up to next-to-leading order. In the first part, we consider several sources of uncertainties with a focus on using different realizations of chiral hyperon-nucleon interactions to estimate three-baryon forces that enter at next-to-next-to leading order. We also demonstrate that the similarity renormalization group evolution of the hyperon-nucleon interactions induces a strong variation of the separation energies. The energies are however strongly correlated which allows one to define a preferred similarity renormalization group parameter for which hypernuclear binding energies can be predicted reliably. With these insights, we present in the second part three examples of recent applications of chiral interactions to hypernuclei. In the first application, we study the predictions for A = 4 and A = 7 hypernuclei based on the version of the hyperonnucleon interaction that yields a large hypertriton binding energy as suggested by the recent experiment of the STAR collaboration. The first predictions for A = 4 − 6 strangeness S = −2 hypernuclei are discussed in the second application. Finally, in the third application, we use the charge-symmetry breaking of A = 4 Λ separation energies to constrain the Λ-neutron interaction.