Abstract We investigate the relative yields of various like and unlike mass hadrons in ultra-relativistic heavy-ion collisions (URHIC). In the framework of thermal model, a strong evidence of strangeness imbalance is observed in the experiments at lower collision energies relative to non-strange particles, particularly pions. The study indicates that like mass particle ratios in the system at the chemical freeze-out in URHIC can be described effectively by considering baryons (antibaryons) as point like as well as finite size particles which imitates hard-core repulsive interactions leading to an excluded volume type effect. In this analysis, we employ the statistical hadron resonance gas model for both cases. A comparison between the two cases is provided. However, the importance of considering baryons (antibaryons) as finite size particles is revealed in the description of baryon to meson ratios. Best fits to particle ratios are obtained using χ 2-minimization procedure. For the case of finite-size baryons (antibaryons), we find that considering their hard-core radii allows us to fit the available antibaryon-to-baryon and baryon (antibaryon)-to-pion ratio experimental data simultaneously quite well with the same model parameter values. Moreover, our results align well with the proton radius puzzle observed in the muonic hydrogen measurement data. Furthermore, the study reveals two distinct chemical freeze-out stages in both cases, where the earlier one corresponds to baryonic (hyperonic) and antibaryonic (antihyperonic) states and a later one to mesonic degrees of freedom. A comparison of freeze-out lines obtained from both the cases is made along with the results of some earlier studies.

The heavy quark symmetries play a necessary role in understanding heavy hadron states. If the Pc(4440) and Pc(4457) states are indeed 〖D ̅^* Σ〗_c^ molecules, they can be classified as heavy quark spin symmetry partners. These acceptances pave the way to clarify spin states that are not determined experimentally. Despite detailed studies on the Pc(4440) and Pc(4457) states, their spin states remain undetermined. While the Breit-Wigner parameterization is the conventional method for obtaining resonance parameters, it is unsuitable for near-threshold resonances such as the Pc(4312), Pc(4440), and Pc(4457) due to its failure to account for the threshold effect. To rectify this limitation, the recently proposed alternative distribution called the Sill is employed to predict their spin states. The use of the Sill values for the Pc(4312), Pc(4440), and Pc(4457) may assist in determining the spin states of the Pc(4440) and Pc(4457).

Parametrization of cascading hadronic reactions is a central tool in hadron spectroscopy for modeling matrix elements and extracting parameters of hadronic states. Implementing the helicity formalism consistently presents challenges, particularly for particles with spin, due to the need to match spin states of final-state particles, an operation known as the Wigner rotation. This paper discusses these challenges in detail and offers solutions, including a practical method for implementation. Equipped with a general algorithm for computing Wigner rotations, we extend the studies to alternative amplitude formulations, the minus-phi and canonical conventions. Published by the American Physical Society 2025

Accessing a full picture of the internal structure of hadrons would be a key topic of hadron physics, with the main motivation to study the strong interaction binding the visible matter. Furthermore, the underlying structure of known exotic states remains an unresolved fundamental issue in hadron physics, which is currently being addressed by hadron physics community. It is well known that electromagnetic characteristics can serve as a distinguishing feature for states whose internal structures are complex and not yet fully understood. The aim of this study is to determine the magnetic moments of vector hidden-charm tetraquark states by making use of QCD light-cone sum rules. In order to achieve this objective, the states mentioned above are considered in terms of the diquark-antidiquark structure. Subsequently, a comprehensive examination is conducted, with four distinct interpolating currents being given particular consideration, as these have the potential to couple with the aforementioned states. It has been observed that there are considerable discrepancies between the magnetic moment results extracted employing different diquark-antidiquark structures. Such a prediction may be interpreted as the possibility of more than one tetraquark with the identical quantum numbers and similar quark constituents but with different magnetic moments. The numerical predictions yielded have led to the conclusion that the magnetic moments of the vector hidden-charm tetraquark states are capable of projecting the inner structure of these states, which may then be used to determine their quark-gluon structure and quantum numbers. In order to provide a comprehensive analysis, the individual quark contributions to the magnetic moments are also examined. As a byproduct, the quadrupole moments of these states are also extracted, and the obtained values differ from zero, which indicates that the charge distribution of these states is not spherical.

One of the hot topics in hadron physics is the study of the new exotic charmonium states and the determination of their internal structure. Another important topic is the study of the magnetic field produced in relativistic heavy-ion collisions and its effects on observables. In this note, we show that we can use ultra-peripheral collisions to address both topics. We compute the cross section for the production of the D⁺D⁻ molecular bound state in photon-photon collisions and also the cross section for π⁰ production in the target induced by the magnetic field of the projectile. Both cross sections are sizeable, and their measurement would be very useful to elucidate the above-mentioned questions.

The production of (multi-)strange hadrons is measured at midrapidity in proton-proton collisions at s = 13 TeV as a function of the local charged-particle multiplicity in the pseudorapidity interval |η| < 0.5 and of the very-forward energy measured by the ALICE Zero-Degree Calorimeters. The latter provides information on the effective energy, i.e. the energy available for particle production in the collision once subtracted from the centre-of-mass energy. The yields of KS0, Λ+Λ¯, and Ξ−+Ξ¯+ per charged-particle increase with the effective energy. In addition, this work exploits a multi-differential approach to decouple the roles of local multiplicity and effective energy in such an enhancement. The results presented in this article provide new insights into the interplay between global properties of the collision, such as the initial available energy in the event, and the locally produced final hadronic state, connected to the charged-particle multiplicity at midrapidity. Notably, a strong increase of strange baryon production with effective energy is observed for fixed charged-particle multiplicity at midrapidity. These results are discussed within the context of existing phenomenological models of hadronisation implemented in different tunes of the PYTHIA 8 event generator.

The SU(3) flavour symmetry for quarks and antiquarks has been demonstrated via the complexified octonion space, where the six complex octonion operators are essentially identical to the SL(3,C) group generators. It has been developed an extensive analysis of the quark flavour theory in the context of complex-octonion space by analyzing the connection between octonions and the SU(3) group. Therefore, it is argued that the extended theory of quark flavors, which preserves the property of non-commutativity, is the complexified variant of octonions. This theoretical model may be further extended to the SU(3) color symmetry, which is regarded as an exact symmetry. In this work, to gain a complete understanding of quark color theory in the framework of complex octonionic space, we have derived the relationship between octonions and the &amp;lt;i&amp;gt;SU(3)c&amp;lt;/i&amp;gt; color group. It has been studied that only eight possibilities of paired gluons are available to provide colorless states of hadrons in order to represent theoretically the octonion glueballs. With the help of Feynman diagrams, we examined the octonionic interaction of color quarks (such as quark-quark, quark anti-quark, and anti-quarks anti-quarks interactions). For the interactions, we have obtained the complex octonion algebraic form of the interaction term, propagator, vertex factor, and color factor. Most importantly, we have examined the conditions for valid and invalid interactions for the complex-octonion formalism.

The climate crisis and the degradation of the world's ecosystems require humanity to take immediate action. The international scientific community has a responsibility to limit the negative environmental impacts of basic research. The HECAP+ communities (High Energy Physics, Cosmology, Astroparticle Physics, and Hadron and Nuclear Physics) make use of common and similar experimental infrastructure, such as accelerators and observatories, and rely similarly on the processing of big data. Our communities therefore face similar challenges to improving the sustainability of our research. This document aims to reflect on the environmental impacts of our work practices and research infrastructure, to highlight best practice, to make recommendations for positive changes, and to identify the opportunities and challenges that such changes present for wider aspects of social responsibility.

In this work, we present an evaluation of subleading effects in the hadronic light-by-light contribution to the anomalous magnetic moment of the muon. Using a recently derived optimized basis, we first study the matching of axial-vector contributions to short-distance constraints at the level of the scalar basis functions, finding that also the tails of the pseudoscalar poles and tensor mesons play a role. We then develop a matching strategy that allows for a combined evaluation of axial-vector and short-distance constraints, supplemented by an estimate of tensor-meson contributions based on simplified assumptions for their transition form factors. Uncertainties are primarily propagated from the axial-vector transition form factors and the variation of the matching scale, but we also consider estimates of the low-energy effect of hadronic states not explicitly included. In total, we obtain aμHLbLsubleading = 33.2(7.2) × 10−11, which in combination with previously evaluated contributions in the dispersive approach leads to aμHLbLtotal = 101.9(7.9) × 10−11.

This Letter presents the first measurement of event-by-event fluctuations of the net number (difference between the particle and antiparticle multiplicities) of multistrange hadrons Ξ^{-} and Ξ[over ¯]^{+} and its correlation with the net-kaon number using the data collected by the ALICE Collaboration in pp, p-Pb, and Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV. The statistical hadronization model with a correlation over three units of rapidity between hadrons having the same and opposite strangeness content successfully describes the results. On the other hand, string-fragmentation models that mainly correlate strange hadrons with opposite strange quark content over a small rapidity range fail to describe the data.

I discuss the theoretical developments related to Strangeness in Quark Matter (SQM) leading up to the SQM2024 conference. These advances include mapping out the Quantum Chromodynamics phase diagram; puzzles that exist in hadron physics from light to heavy particles; and relativistic hydrodynamics with the inclusion of spin and magnetic fields.

The PUNCH4NFDI consortium, funded by the German Research Foundation for an initial period of five years, gathers various physics communities - particle, astro-, astroparticle, hadron and nuclear physics - from different institutions embedded in the National Research Data Infrastructure initiative. The goal of PUNCH4NFDI is the establishment of FAIR data management solutions for the participating communities. The federated compute and storage infrastructures made available to the consortium, Compute4PUNCH and Storage4PUNCH, comprise a variety of heterogeneous compute and storage systems. The compute resources are managed by an overlay batch system and COBalD/TARDIS meta-schedulers. The TARDIS resource manager is responsible for the provisioning of resources and their integration in the overlay batch system based on HTCondor, while the COBalD resource balancer optimises the resource utilization by matching the actual demand for a given type of resources. The access to the resources is standardised using a token-based authentication and authorization infrastructure. The refreshment of short-lived access tokens is automated using the HTCondor Credential Manager and the MyToken service. Login nodes define single entry points to the federation, while the use of containers and the CERN Virtual Machine File System ensures a scalable provisioning of virtualized software environments. The latest developments are presented, including the access tokens management and the integration of Compute4PUNCH as a compute backend of the REANA analysis platform.

Quantum gravity is an attempt to resolve incompatibilities between general relativity and quantum theory. Primordial field theory incorporates gravity and electrodynamics and has derived fermion mass gap, half integral spin, and fractional charges. This paper extends PFT to hadron physics with a “solenoidal flux”-based explanation of quark confinement differing significantly from Lattice QCD “color flux”-based construction. The theory is presented qualitatively and used to predict hadronic and nuclear properties. Electrodynamic-based analogies help yield numerical results far more intuitively than corresponding QCD results. The origins of QCD and PFT are discussed. A more quantitative description of hadron dynamics is in progress.

PANDA is the main hadron physics addressing experiment of the future FAIR (Facility for Antiproton and Ion Research) center at Darmstadt, Germany. Located at the HESR antiproton storage ring the PANDA detector is optimized for physics of the weak and strong interactions in the charm sector: Search for new and exotic states of matter, precise determination of quantum numbers, masses and widths of hadronic resonances and deeper insights in the structure of hadrons. The detector consists of a target spectrometer built around the interaction region of antiprotons carrying momenta of 1.5-15 GeV/c with a fixed hydrogen target and a forward spectrometer. Its design is based on compactness and cost saving while achieving high resolution, rate capability and physics selectivity. In the PANDA target spectrometer the electromagnetic calorimeter is composed of three subdetectors based on lead tungstate crystals operated at -25 degrees C. A barrel structure built from 11360 crystals will be closed in up- and downstream direction by two endcaps containing 524 and 3856 crystals, respectively. The upstream located forward endcap has been completed with vacuum photo tetrode read-out crystal submodules and was operated at two beam times in 2023 at the Juelich Cooler Synchrotron with a 2.5 GeV/c proton beam. Besides the detector setup, the cooling concept, and beam test results will be presented.

The Geant4 hadronic physics sub-library includes an extended set of models for highand low-energy hadronic interactions. We report on recent developments in the Geant4 nuclear de-excitation module, which is used by many Geant4 models to simulate the de-excitation of nuclear recoils produced in nuclear reactions. These processes significantly influence hadronic shower shape and energy deposition. We present the structure of the de-excitation module, and compare Geant4 predictions with thin-target experimental data, using different Geant4 hadronic physics models. These comparisons are performed for Geant4 version 11.3, which was publicly released in December 2024.

The production mechanism of (anti)nuclei in ultrarelativistic hadronic collisions is under debate in the scientific community. Two successful models used for the description of the experimental measurements are the statistical hadronization model and the coalescence approach. In the latter, multibaryon states are assumed to be formed by the coalescence of baryons that are close in phase-space at kinetic freeze-out. Given the collimated emission of nucleons in jets, the available phase-space is limited. As a result, the production of nuclear states through coalescence in jets is expected to be enhanced compared to production in underlying events. In this contribution, the results for the coalescence parameter B 2 , which quantifies the formation probability of deuterons by coalescence, measured in and out of jets with the ALICE detector at the Large Hadron Collider, are presented and discussed in the context of the coalescence model.

The first measurement of H Λ 3 and H ‾ Λ ‾ 3 differential production with respect to transverse momentum and centrality in Pb–Pb collisions at s NN = 5.02 TeV is presented. The H Λ 3 has been reconstructed via its two-charged-body decay channel, i.e., H Λ 3 → 3 He + π − . A Blast-Wave model fit of the p T -differential spectra of all nuclear species measured by the ALICE collaboration suggests that the H Λ 3 kinetic freeze-out surface is consistent with that of other nuclei. The ratio between the integrated yields of H Λ 3 and He 3 is compared to predictions from the statistical hadronisation model and the coalescence model, with the latter being favoured by the presented measurements.

The transverse-momentum-dependent distributions (TMDs), which are defined by gauge-invariant 3D parton correlators with staple-shaped lightlike Wilson lines, can be calculated from quark and gluon correlators fixed in the Coulomb gauge on a Euclidean lattice. These quantities can be expressed gauge invariantly as the correlators of Coulomb-gauge-dressed fields, which reduce to the standard TMD correlators under principal-value prescription in the infinite boost limit. In the framework of large-momentum effective theory, a quasi-TMD defined from such correlators in a large-momentum hadron state can be matched to the TMD via a factorization formula, whose exact form is derived using soft collinear effective theory and verified at one-loop order. Compared to the currently used gauge-invariant correlators, this new method can substantially improve statistical precision and simplify renormalization for the time-reversal-even TMDs, which will greatly enhance the predicative power of lattice QCD in the nonperturbative region. Published by the American Physical Society 2024

The phenomenology of hadronic states at high energy is well described in the framework of quantum chromodynamics. By the other hand, that is the description of the low-energy regime, e.g., mesoniclike states, requires the introduction of effective degrees of freedom, a condition resulting from confinement. As an alternative to lattice gauge calculations, and own to the similarities with other quantum many-body systems, we have adopted a nonperturbative scheme where quarks are treated as quasiparticles. These quasiquarks interact between them, allowing mesonlike states to be described as collective superposition of quasiquark pairs. The results of the calculations, performed in the context of the random phase approximation method, show that this scheme is a suitable one to describe meson states up to energies of the order of couple of GeV. Published by the American Physical Society 2024

During the 2015–2018 data-taking period, the Large Hadron Collider delivered proton-proton bunch crossings at a centre-of-mass energy of 13 TeV to the ATLAS experiment at a rate of roughly 30 MHz, where each bunch crossing contained an average of 34 independent inelastic proton-proton collisions. The ATLAS trigger system selected roughly 1 kHz of these bunch crossings to be recorded to disk. Offline algorithms then identify one of the recorded collisions as the collision of interest for subsequent data analysis, and the remaining collisions are referred to as pile-up.Pile-up collisions represent a trigger-unbiased dataset, which is evaluated to have an integrated luminosity of 1.33 pb−1 in 2015–2018. This is small compared with the normal trigger-based ATLAS dataset, but when combined with vertex-by-vertex jet reconstruction it provides up to 50 times more dijet events than the conventional single-jet-trigger-based approach, and does so without adding any additional cost or requirements on the trigger system, readout, or storage. The pile-up dataset is validated through comparisons with a special trigger-unbiased dataset recorded by ATLAS, and its utility is demonstrated by means of a measurement of the jet energy resolution in dijet events, where the statistical uncertainty is significantly reduced for jet transverse momenta below 65 GeV.