The octet and decuplet <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>S</mi><mi>U</mi><msub><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow><mi>f</mi></msub></mrow></math> baryons are studied with the Polyakov, Nambu, and Jona-Lasinio model, in a diquark-quark approach, via the resolution of the Bethe-Salpeter equation. This work includes estimations of their masses according to the temperature and the baryonic density, with or without the isospin symmetry. Several improvements of this modeling are proposed and tested: the treatment of the baryons' unstable regime, the inclusion of the diquark momentum dependence, the possibility to model baryons without the static approximation, the description of the octet baryons via scalar and axial flavor components, and the use of a Nambu and Jona-Lasinio diquark propagator instead of a structureless one. The effects of the color superconductivity on the nucleon mass are also investigated. Certain of the mentioned improvements can be applied simultaneously. The advantages and limitations of each of them are highlighted.

France

Eric Blanquier

Baryons in the Nambu–Jona-Lasinio models

We present a study of the single- and multistrange particle productions in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV using the PACIAE 4.0 model. The effects of color reconnection (CR), rope hadronization (RH), as well as partonic and hadronic rescatterings (PRS and HRS) on their productions are investigated. There are two kinds of CR considered: the multiparton-interactions-based CR (MPI-CR) and the quantum-chromodynamics-based CR (QCD-CR). The four mechanisms studied have little effect on kaon production. The QCD-CR scheme incorporating the junction topology gives an enhanced baryon production, but it is still not enough to describe the data of integrated yields of strange baryons. The combination of QCD-CR and the RH scheme together with flavor ropes (FR) and string shoving (SS) provides a good description for the data of strange baryon production. For the heavier <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ξ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math> baryons, an improved <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>QCD</mi><mtext>−</mtext><mi>CR</mi><mo>+</mo><mi>FR</mi></mrow></math> scheme with stronger tension is required, whereas the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>QCD</mi><mtext>−</mtext><mi>CR</mi><mo>+</mo><mi>FR</mi><mo>+</mo><mi>SS</mi></mrow></math> scheme adequately describes <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Λ</mi></math> production. PRS has a weak effect, but HRS exerts a promoting effect on the production of multistrange baryons (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ξ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math>).

China

Wei Lei

Qiang Wang

An-Ke Lei

Zhi-Lei She

Jia-Xin Gao

Dai-Mei Zhou

Yu-Liang Yan

Hua Zheng

Wen-Chao Zhang

Ben-Hao Sa

Strangeness production in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV in the PACIAE model

Motivated by the LHCb Collaboration's observation of the doubly charmed tetraquark state <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub><mrow><mo>(</mo><mn>3875</mn><mo>)</mo></mrow></mrow></math>, we systematically explore the potential existence of doubly charmed pentaquark states using the resonating group method within the quark delocalization color screening model framework. The effective potential of the two involved hadrons and the bound-state dynamics are included in the present work. Moreover, we have also calculated the scattering phase shifts of open channels with channel coupling, aiming to identify possible resonance states. Our estimations suggest that the existence of a bound state with quantum numbers <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>I</mi><mrow><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo></mrow><mo>=</mo><mfrac><mn>3</mn><mn>2</mn></mfrac><mrow><mo>(</mo><msup><mfrac><mn>5</mn><mn>2</mn></mfrac><mo>−</mo></msup><mo>)</mo></mrow></mrow></math> and a mass of approximately 4461.7 MeV. Furthermore, five resonance states are predicted through coupled-channels analysis, which are <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi mathvariant="normal">Ξ</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub><mi>ρ</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub><msup><mi>D</mi><mo>*</mo></msup></mrow></math> with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>I</mi><mrow><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo></mrow><mo>=</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mrow><mo>(</mo><msup><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>−</mo></msup><mo>)</mo></mrow></mrow><mo>,</mo><mo> </mo><mrow><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><msup><mi>D</mi><mo>*</mo></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msubsup><mi mathvariant="normal">Σ</mi><mrow><mi>c</mi></mrow><mo>*</mo></msubsup><msup><mi>D</mi><mo>*</mo></msup></mrow></math> with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>I</mi><mrow><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo></mrow><mo>=</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mrow><mo>(</mo><msup><mfrac><mn>3</mn><mn>2</mn></mfrac><mo>−</mo></msup><mo>)</mo></mrow></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub><msup><mi>D</mi><mo>*</mo></msup></mrow></math> with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>I</mi><mrow><mo>(</mo><msup><mi>J</mi><mi>P</mi></msup><mo>)</mo></mrow><mo>=</mo><mfrac><mn>3</mn><mn>2</mn></mfrac><mrow><mo>(</mo><msup><mfrac><mn>1</mn><mn>2</mn></mfrac><mo>−</mo></msup><mo>)</mo></mrow></mrow></math>, respectively. The existence of these predicted doubly charmed pentaquark states needs to be supported by experimental measurements and discoveries. We hope future experiments will provide evidence for these states.

Xuejie Liu

Yue Tan

Xiaoyun Chen

Dianyong Chen

Hongxia Huang

Jialun Ping

Investigation of the doubly charmed analog of the <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>P</mi><mi>c</mi></msub></math> states

We investigate dimuon production in the context of a first-order phase transition in QCD matter using a chiral fluid dynamics model. This approach incorporates nonequilibrium effects such as entropy production and reheating, which emerge during the dynamical evolution through a first-order phase transition. By comparing equilibrium and nonequilibrium scenarios across a range of beam energies (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>2.2</mn><mo>–</mo><mn>6.2</mn></mrow></math> GeV), we analyze the resulting invariant mass spectra. Our results reveal a substantial enhancement of dilepton yields in the nonequilibrium scenario, particularly pronounced at lower beam energies, where reheating leads to a prolonged lifetime of the fireball and increased emission. The enhancement persists even after normalizing to pion multiplicities, indicating sensitivity beyond effects of entropy production.

Malaysia

Mohamad Lukman Aidid Mohd Yusoff

Norhasliza Yusof

Hasan Abu Kassim

Germany

Jan Steinheimer

Marcus Bleicher

Thailand

Apiwit Kittiratpattana

Ayut Limphirat

Christoph Herold

Electromagnetic probes as signatures for a first-order QCD phase transition

Emission asymmetries between pions and kaons reflect the role of the hadronic phase in the cooling of a droplet of deconfined strongly interacting matter. This study compares results from two models at the same collision energy of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV to investigate how interactions in the hadronic phase affect particle emission. The first model, the integrated hydrokinetic model (iHKM), provides a complete description of all stages of the evolution; from the initial scattering and thermalization to the final hadronic state, while the second model, LQTH <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>LHYQUID</mi><mo>+</mo><mrow><mi>THERMINATOR</mi><mn>2</mn></mrow><mo>)</mo></mrow></math>, assumes a sudden conversion into hadrons, neglecting further interactions. To increase the sensitivity to hadronic interactions, the analysis was performed as a function of the pair transverse velocity for pairs with nearly equal velocity vectors. The obtained predictions are compared with previously measured ALICE data at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>2.76</mn></mrow></math> TeV as a function of the cube root of the average particle multiplicity density at midrapidity, showing that both radii and emission asymmetries scale with particle multiplicity, regardless of the collision energy. The iHKM reproduces the measured trends both qualitatively and quantitatively, whereas the LQTH model requires additional parameters—in particular, a time delay in the emission of kaons—to achieve quantitative agreement. The comparative analysis also indicates a possible nonmonotonic behavior of the asymmetry as a function of transverse velocity, and a constant scaling of the ratio between the emission asymmetry and femtoscopic radii with particle multiplicity. These results highlight the importance of including interactions in the hadronic stage for a complete description of the emission function.

Poland

P. Chakraborty

G. Kornakov

A. Kisiel

Ukraine

Yu. M. Sinyukov

V.M. Shapoval

India

S. Dash

Pion-kaon femtoscopy as a probe of the space-time emission anisotropies due to interactions at the hadronic stage of matter evolution in relativistic heavy-ion collisions

Vector meson photoproduction is an important probe of nuclear structure. Light vector mesons are most sensitive to <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>low</mi><mtext>−</mtext><mi>x</mi></mrow></math> structure, as long as they are not too light for perturbative QCD calculations. The <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>ρ</mi><mo>′</mo></msup></math> is of interest as an intermediate mass state (between the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ρ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math>) that is easier to detect than the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ϕ</mi></math>. Using HERA data on proton targets, we make projections for lead/gold targets in ultraperipheral collisions (UPCs) at the CERN Large Hadron Collider and the BNL Relativistic Heavy Ion Collider, and for <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>e</mi><mi>p</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>e</mi><mi>A</mi></mrow></math> collisions at a future electron-ion collider (EIC). We compare the UPC projections with ALICE data, and constrain the branching ratio divided by the square of the photon-<math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>ρ</mi><mo>′</mo></msup></math> coupling. The data prefer large couplings and small branching ratio, probably less than 25%. The photon-meson coupling predicted by generalized vector meson dominance does not fit the data. The HERA <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>e</mi><mi>p</mi></mrow></math> and ALICE UPC <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>e</mi><mi>Pb</mi></mrow></math> data exhibit very similar <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mn>4</mn><mi>π</mi></mrow></math> mass spectra, indicating that, if the system is composed of two resonances, the products of their photon couplings with their four-pion branching ratios are similar. The predicted rates are high for both UPCs and the EIC. The <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>ρ</mi><mo>′</mo></msup><mo>→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></mrow></math> decay can be observed at the EIC with high efficiency. In <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>e</mi><mi>p</mi></mrow></math> collisions at the highest energy, the forward B0 detector is needed to observe this channel down to the lowest achievable <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Bjorken</mi><mtext>−</mtext><mi>x</mi></mrow></math> values.

United States

Neha Devi

Janet Seger

Minjung Kim

Spencer R. Klein

Photoproduction and detection of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>ρ</mi><mo>′</mo></msup><mo>→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></mrow></math> decays in ultraperipheral collisions and at an electron-ion collider

It has been assumed that nuclear modification does not exist in the longitudinal-transverse structure-function ratio <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>R</mi><mi>N</mi></msub><mo>=</mo><msubsup><mi>F</mi><mi>L</mi><mi>N</mi></msubsup><mo>/</mo><mrow><mo>(</mo><mn>2</mn><mi>x</mi><msubsup><mi>F</mi><mn>1</mn><mi>N</mi></msubsup><mo>)</mo></mrow></mrow></math> in lepton deep inelastic scattering. This assumption is widely used in obtaining structure functions of the “nucleon” from nuclear data such as the deuteron ones. However, nuclear modifications do exist theoretically at least in medium- and large-<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x</mi></math> regions because nucleons in a nucleus move in any direction, which is not necessarily the longitudinal direction of the virtual-photon or weak-boson momentum in lepton scattering. Because of this transverse motion, the nucleon's transverse and longitudinal structure functions should mix with each other in nuclei with the mixture probability proportional to the nucleon's transverse momentum squared <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msubsup><mover accent="true"><mi>p</mi><mo>⃗</mo></mover><mi>T</mi><mrow><mspace width="0.16em"></mspace><mspace width="0.16em"></mspace><mn>2</mn></mrow></msubsup><mo>/</mo><msup><mi>Q</mi><mn>2</mn></msup></mrow></math>. In this work, numerical results are explicitly shown regarding such nuclear modifications in the deuteron. These nuclear modifications are important for determining precise structure functions of the nucleon. Furthermore, modifications of <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mi>N</mi></msub></math> should be investigated also at small <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x</mi></math> by the future electron-ion collider to find interesting gluon dynamics in nuclei. Hopefully, this nuclear effect of <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mi>N</mi></msub></math> could be found by future experimental measurements at lepton accelerator facilities.

Japan

S. Kumano

Existence of nuclear modifications of the nucleon longitudinal-transverse structure-function ratio

EPOS4 is based on a sophisticated (recently significantly improved) parallel-primary-scattering scenario followed by a hydrodynamic expansion, for all collision systems, from small ones such as proton-proton <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>p</mi><mi>p</mi><mo>)</mo></mrow></math> to large ones such as lead-lead (PbPb). Having already reported on identified particle spectra in recent publications (providing information about radial flow), I discuss here the multiplicity dependence of multiparticle cumulants and flow harmonics, to better understand collectivity in small systems. The model is not particularly tuned for flow results, but it is a “general purpose” approach, trying to accommodate various types of observables with the same model.

K. Werner

Flow in small systems in the EPOS4 approach for high-energy scattering

Hadronic resonances, with lifetimes of a few <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>fm</mi><mo>/</mo><mi>c</mi></mrow></math> are key tools for studying the hadronic phase in high-energy collisions. This work investigates resonance production in pp collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13.6</mn><mspace width="0.28em"></mspace><mi>TeV</mi></mrow></math> and in Pb-Pb collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.36</mn><mspace width="0.28em"></mspace><mi>TeV</mi></mrow></math> using the EPOS4 model. The EPOS4 model provides the capability of switching the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) ON or OFF, allowing the study of final-state hadronic interactions in the hadronic phase. Although this study is primarily focused on understanding the production of hadronic resonances, we also investigate the production of strange and nonstrange hadrons in relation to rescattering, regeneration, baryon-to-meson production, and strangeness enhancement, using transverse momentum (<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math>) spectra and particle ratios. Rescattering effects and strangeness enhancement play an important role in the low-<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math> region, where soft, nonperturbative processes dominate particle production. At intermediate <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math>, the baryon-to-meson yield ratios show an enhancement, and the strong mass-dependent radial flow observed for baryons in the most central Pb-Pb collisions reflects the interplay between hadronization dynamics and collective effects. The average <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math> scaled with the reduced hadron mass (i.e., the mass divided by the number of valence quarks) is examined, revealing a deviation from a linear trend for short-lived resonances, attributed to hadronic phase effects. By analyzing the yield ratios of short-lived resonances to stable hadrons in pp and Pb-Pb collisions, the time duration (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>τ</mi></math>) of the hadronic phase as a function of average charged multiplicity is estimated. The results show that <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>τ</mi></math> increases with increasing multiplicity and system size, also exhibiting a nonzero value for high-multiplicity pp collisions. It is found that the production of baryons such as nonstrange (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>p</mi></math>), strange (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Λ</mi></math>), and multistrange (<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ξ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math>) in the most central Pb-Pb collisions is influenced by competing processes of strangeness enhancement and baryon-antibaryon annihilation. Comparing these findings with measurements at energies available at the CERN Large Hadron Collider offers valuable insights into the underlying dynamics of the hadronic phase and their production dynamics.

Vikash Sumberia

Dukhishyam Mallick

Sanjeev Singh Sambyal

Nasir Mehdi Malik

Examining hadronic resonance dynamics at energies available at the CERN Large Hadron Collider: Insights from EPOS4

In this study we examine the impact of the initial stage and dynamical evolution on final-state observables in heavy-ion collisions. For this goal we develop a novel approach, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>EPOSir</mi><mo>+</mo><mi>PHSDe</mi></mrow></math>, which employs energy-conserving multiple parallel scattering approach, accommodating factorization and saturation (EPOS) initial conditions as the starting point for parton and hadron evolution within the parton-hadron-string dynamics (PHSD) microscopic transport approach. By examining the space-time evolution of matter in this model and comparing to EPOS (which starts with an <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>S</mi></mrow></math>-matrix approach for parallel scatterings for the initial conditions and uses a hydrodynamic evolution for the quark-gluon plasma stage with the UrQMD as afterburner) and PHSD (which starts with primary high-energy <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mi>N</mi></mrow></math> scattering realized via the LUND string model and continues with fully microscopic transport dynamics for strongly interacting partonic and hadronic matter), we identify the key differences in the final particle distributions among the three approaches. Our analysis focuses on rapidity, transverse momentum spectra, and flow harmonics <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>v</mi><mn>2</mn></msub></math> for <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Au</mi><mo>+</mo><mi>Au</mi></mrow></math> collisions at the invariant energy of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>200</mn></mrow></math> GeV. We find a dominant influence of dynamical evolution over the initial conditions on the final observables.

Mahbobeh Jafarpour

JINR

Vadym Voronyuk

Klaus Werner

Elena Bratkovskaya

Damien Vintache

Disentangling initial-state and evolution effects in heavy-ion collisions using EPOS and PHSD