Search

The study of heavy-flavour mesons and baryons in hadronic collisions provides unique access to the properties of heavy-quark hadronisation in the presence of large partonic densities, where new mechanisms of hadron formation beyond in-vacuum fragmentation can emerge. Performing these measurements in intervals of charged-particle multiplicities across different collision systems provides sensitivity to understand whether different hadronisation mechanisms are at play in small and large hadronic colliding systems. In this contribution, a selection of the latest charm and beauty production measurements in proton–proton (pp) collisions is presented, which can shed light on the modification of the heavy-quark hadronisation mechanisms with respect to leptonic collisions. New published results of the production of all prompt charm ground states in pp collisions at √S = 13 TeV, which allowed us to measure the charm fragmentation fractions and the total cc production cross section at midrapidity, will be shown. The new final measurement of non-prompt (i.e. originating from beauty-hadron decays) Λc+ baryons in the same collisions system will be discussed to provide a quantitative comparison between the hadronisation properties of beauty and charm hadrons. New measurements of Ξc0 production as a function of charged-particle multiplicity in pp collisions at √S = 13, and of Ξc0 production in p–Pb collisions at √SNN = 5.02 TeV, will be also presented, shedding further light on the hadronisation of charm-strange baryons in different colliding systems. [ABSTRACT FROM AUTHOR]

Heavy meson production in reactions with nuclei is an active new frontier to understand QCD dynamics and the process of hadronization in nuclear matter. Measurements in various colliding systems at RHIC and LHC, including Pb-Pb, Xe-Xe, O-O, p-Pb, and p-O, enable precision tests of the medium-size, temperature, and mass dependencies of the in-medium parton propagation and shower formation. We employ a coupled DGLAP evolution framework that takes advantage of splitting functions recently obtained in softcollinear effective theory with Glauber gluons (SCETG) and hard thermal loop (HTL) motivated collisional energy loss effects. With jet quenching effects constrained to the nuclear modification factor of charged hadrons in Pb-Pb collisions at 5.02 TeV, we present predictions for light and heavy-meson in Xe-Xe, O-O and p-Pb collisions at the LHC.We find that the nuclear modification scales non-trivially with the quark mass and medium properties. In particular, there can be sizeable collision-induced attenuation of heavy mesons in small systems such as oxygen-oxygen and high-multiplicity p-Pb events. Finally, we analyze the impact of different models of initial-state parton dynamics on the search for QGP signatures in small colliding systems. [ABSTRACT FROM AUTHOR]

We explore the consequences of gluonic hot spots inside the proton for the initial eccentricities in a proton-nucleus collision, and the constraints on the parameters describing these hot spots from coherent and incoherent exclusive vector meson production cross sections in deep inelastic scattering. We show that geometric fluctuations of hot spots inside the proton are the dominant source of eccentricity whereas color charge fluctuations only give a negligible correction. We find that the coherent cross section is sensitive to both the size of the target and the structure of the probe. The incoherent cross section is dominated by color fluctuations at small transverse momentum transfer |t|, by proton and hot spot sizes as well as the structure of the probe at medium |t| and again by color fluctuations at large |t|. [ABSTRACT FROM AUTHOR]

Heavy quarks, i.e. charm and beauty, are produced in the initial stage of heavy-ion collisions, on a time scale shorter than the medium formation time, and are sensitive to the large initial magnetic field produced perpendicular to the reaction plane, defined by the impact parameter direction and beam direction, in non-central heavy-ion collisions. In the presence of a large initial magnetic field, the charm quark can be polarised. The quark polarisation is then expected to be transferred to the hadron in the hadronisation process. We will present the first measurement of D*+ polarisation in Pb–Pb collisions at √SNN = 5.02 TeV, exploiting the large data sample collected by the ALICE Collaboration during the LHC Run 2 and we will compare these new results with the existing J/ψ polarisation measurements. [ABSTRACT FROM AUTHOR]

Within the Color Glass Condensate framework, we demonstrate that exclusive vector meson production at high energy is sensitive to the geometric deformation of the target nucleus and subnucleon scale fluctuations. Deformation of the nucleus enhances the incoherent cross section in the small |t| region. Subnucleon scale fluctuations increase the incoherent cross section in the large |t| region. In ultra-peripheral collisions (UPCs), larger deformation leads to a wider distribution of the minimal impact parameter Bmin required to produce a UPC. This, together with larger incoherent cross sections for larger deformation, results in smaller extracted radii. Our results demonstrate great potential for future studies of nuclear structure in UPCs and electron-ion collisions. [ABSTRACT FROM AUTHOR]

We present a unique signal of medium response to jet quenching: the enhancement of baryon-to-meson ratios for associated particles at intermediate transverse momentum around the triggered quenched jets. Since the lost energy from the jets can diffuse to large angles, we expect that such baryon-to-meson enhancement is stronger for larger distance with respect to the jet axis. Our prediction can be tested by future experiments. [ABSTRACT FROM AUTHOR]

Quasi-Particle Model (QPM) has been developed to study charm quark dynamics in ultra-relativistic heavy-ion collisions with good description of D mesons RAA(pT) and v2,3(pT) and leading to the evaluation of the spatial diffusion coefficient Ds(T). With an event-by-event full Boltzmann transport approach followed by a hybrid hadronization via coalescence plus fragmentation, we show RAA(pT), v2(pT) down to pT → 0 for D and B mesons. We find that QPM approach is able to correctly predict first available data on RAA(pT) and v2(pT) of single-electron from B mesons decays measured by ALICE. A significant breaking of the expected scaling of the thermalization time τth with MQ/T is found. Charm quark Ds(T) is about 50% larger than the asymptotic value for MQ → ∞, while the bottom Ds(T) is only 20% higher. In the infinite mass limit the Ds(T) is consistent with recent lQCD calculations with dynamical quarks. [ABSTRACT FROM AUTHOR]

Our investigation focuses on the rapidity-dependent directed flow, v1(y), of identified hadrons in Au+Au collisions across a broad range of √SNN from 7.7 to 200 GeV. Employing a (3+1)-dimensional hybrid framework, our study successfully reproduces the characteristic features of the measured v1(y) for both mesons and baryons across the considered beam energies. Notably, our analysis reveals the constraining power of baryonic v1(y) on the initial baryon stopping mechanism. Together with mesonic v1(y), the directed flow serves as a crucial tool for probing the equation of state governing dense nuclear matter at finite chemical potentials. [ABSTRACT FROM AUTHOR]

In these proceedings, we present new measurements from STAR of the global spin alignment(ρ00) of ϕ mesons in Au+Au collisions at √SNN = 19.6, 14.6 GeV using BES-II data and of J/ψ mesons in isobar collisions 4496Ru + 4496Ru and 4096Zr + 4096Zr at √SNN = 200 GeV. The energy-dependent spin alignment for ϕ mesons from BES-II data is consistent with that published from BES-I and showcases a significant improvement in precision. We performed a new measurement assessing the rapidity dependence of ϕ meson ρ00, and our findings are consistent with theoretical predictions. The global spin alignment of J/ψ mesons with respect to first order event plane aligns with a value of 1/3 within the statistical error. Additionally, we discuss the procedure of measuring the global spin alignment of ρ0 mesons at RHIC and provide the projection for errors. [ABSTRACT FROM AUTHOR]

The task of identifying B meson flavor at the primary interaction point in the LHCb detector is crucial for measurements of mixing and timedependent CP violation. Flavor tagging is usually done with a small number of expert systems that find important tracks to infer the B meson flavor from. Recent advances show that replacing all of those expert systems with one ML algorithm that considers all tracks in an event yields an increase in tagging power. However, training the current classifier takes a long time and it is not suitable for use in real time triggers. In this work we present a new classifier, based on the DeepSet architecture. With the right inductive bias of permutation invariance, we achieve great speedups in training (multiple hours vs 10 minutes), a factor of 4-5 speed-up in inference for use in real time environments like the trigger and less tagging asymmetry. For the first time we investigate and compare performances of these "Inclusive Flavor Taggers" on simulation of the upgraded LHCb detector for the third run of the LHC. [ABSTRACT FROM AUTHOR]

Athena is the software framework used in the ATLAS experiment throughout the data processing path, from the software trigger system through offline event reconstruction to physics analysis. For Run 3 data taking (which started in 2022) the framework has been reimplemented into a multi-threaded framework. The ATLAS High Level Trigger (HLT) system has also been updated to rely to a greater extent than in Run 2 (data taking between 2015-2018) on common solutions between online and offline software. We present the now operational new HLT system, report on how the system was tested, commissioned and optimised. In addition, we show developments that have been made in tools that are used to monitor and configure the HLT, some of which are designed from scratch for Run 3. [ABSTRACT FROM AUTHOR]

The data acquisition (DAQ) of the Compact Muon Solenoid (CMS) experiment at CERN, collects data for events accepted by the Level-1 Trigger from the different detector systems and assembles them in an event builder prior to making them available for further selection in the High Level Trigger, and finally storing the selected events for offline analysis. In addition to the central DAQ providing global acquisition functionality, several separate, so-called "MiniDAQ" setups allow operating independent data acquisition runs using an arbitrary subset of the CMS subdetectors. During Run 2 of the LHC, MiniDAQ setups were running their event builder and High Level Trigger applications on dedicated resources, separate from those used for the central DAQ. This cleanly separated MiniDAQ setups from the central DAQ system, but also meant limited throughput and a fixed number of possible MiniDAQ setups. In Run 3, MiniDAQ-3 setups share production resources with the new central DAQ system, allowing each setup to operate at the maximum Level-1 rate thanks to the reuse of the resources and network bandwidth. Configuration management tools had to be significantly extended to support the synchronization of the DAQ configurations needed for the various setups. We report on the new configuration management features and on the first year of operational experience with the new MiniDAQ-3 system. [ABSTRACT FROM AUTHOR]

The study of single-nucleon transfer reactions for the 18O+48Ti system was pursued at the energy of 275 MeV as part of a more systematic study which is undertaken within the NUMEN and NURE experimental campaigns. The aim is to measure the complete set of available reaction network which are characterized by the same initial and final-state wavefunctions as the more suppressed double charge exchange reactions. Understanding the degree of competition between successive nucleon transfer and double charge exchange reactions is crucial for the description of the meson-exchange mechanism. In this respect, angular distribution measurements for one- and twonucleon transfer reactions for the 18O+48Ti system were carried out at theMAGNEX facility of INFN-LNS in Catania. An overview of the data analysis for the 48Ti(18O,19F)47Sc and 48Ti(18O,17O)49Ti reactions will be presented. [ABSTRACT FROM AUTHOR]

Abstract. Relativistic nucleus-nucleus collisions offer a unique possibility for studying nuclear matter under the influence of high temperature and pressure. During the collision a system of interacting nucleons, resonances, and mesons, called hadronic fireball, is created. HADES is a unique experiment capable of simultaneously measuring all three species of pions for this energy regime. Results on neutral pion production in Ag + Ag collisions at √SNN = 2.55 GeV (beam energy 1.58 A GeV) with 14 billion collected events will be presented. A measurement of a directed and elliptic flow, and yields of neutral pions corrected for detector acceptance and efficiency will be shown with respect to transverse momentum and rapidity for certain centrality classes; and further compared with the data, and charged pion data measured in the same experiment. In addition, the obtained results will be confronted with up-to-date model calculations. [ABSTRACT FROM AUTHOR]

Abstract. New isobar models for the photoproduction of kaons off the proton target were constructed utilizing a consistent formalism for exchanges of high-spin resonances and energy-dependent widths of nucleon resonances. For adjusting the free parameters of the model to experimental data we employ reg-ularization techniques, which prevent us from overfitting the data. We analysed the plentiful data on the K+Λ channel as well as the recent data on K+σ− channel and compare the results with data. [ABSTRACT FROM AUTHOR]

Abstract. A theoretical model of two-pion photoproduction is presented. The model encodes the prominent ρ(770) resonance and the expected leading background contribution coming from the Deck mechanism. To validate the model, angular moments are computed and compared with the CLAS dataset. After fitting a number of free parameters, the model provides a good description of the data. [ABSTRACT FROM AUTHOR]

Abstract. The existence of the nucleonic pentaquark resonances Pc (4312), Pc(4380), Pc(4440) and Pc(4457), established by the LHCb collaboration, has been one of the major discoveries in hadron physics in the latest years. This has been followed by the discovery of pentaquarks with one unit of strangeness, Pcs(4338) and Pcs(4457). Most of these states can be understood as hadronic molecules, namely bound states of a sufficiently attractive meson-baryon interaction. A widely used model, based on unitarized meson-baryon amplitudes obtained from vector meson exchange interactions derived from the hidden gauge formalism, which predicted these states prior to their discovery, is also predicting the existence of pentaquarks with double strangeness content, at around 4500 MeV and 4600 MeV [1]. Our model also suggest that one of these double strangeness pentaquarks can be seen in the weak decay of the Eb baryon into J/ΨϕΞ. A detailed study of this reaction is still under investigation, but in these proceedings we shall show some preliminary results, which confirm the possibility of observing traces of S=-2 pentaquark in invariant mass spectra of J/ΨΞ pairs produced in the decays Ξb→ J/ΨϕΞ. [ABSTRACT FROM AUTHOR]

Abstract. We first review recent theoretical results related to the ϕ-N and ϕ-nucleus interactions. Thereafter, preliminary results of transport simulations of 12 GeV pA reactions to study the corresponding dilepton spectrum measured at the KEK E325 experiment are presented. [ABSTRACT FROM AUTHOR]

The NA62 experiment at CERN collected the world's largest dataset of charged kaon decays in 2016–2018, leading to the first measurement of the branching ratio of the ultra-rare K+ → π+vv− decay, based on 20 candidates. Recent results from analyses of K+ → π0e+vγ, K+ → π+µ+µ− and K+ → π+γγ decays, using a data sample recorded in 2017-2018, are reported. Preliminary results of the first observation and analysis of the K± → π0π0µ±v decay, based on the NA48/2 data collected in 2003-2004, are also shown. [ABSTRACT FROM AUTHOR]

Abstract. We investigate the D*K* and Dsρ* interaction in coupled channels within the hidden gauge formalism. A structure is developed around their thresholds, short of producing a bound state, which leads to a peak in the Ds+π¯ mass distribution in the B0 → D¯0 Ds+π¯ decay compatible with the experimental data. We conclude that the interaction between the D*K* and Dsρ* is essential to produce the cusp structure that we associate to the recently seen Tcs¯(2900), and that its experimental width is mainly due to the decay width of the ρ meson. The peak obtained together with a smooth background reproduces fairly well the experimental mass distribution observed in the B0 → D¯0 Ds+π¯ decay. [ABSTRACT FROM AUTHOR]

Despite mesons being one of the longest known type of particles, there are still many open questions. Besides well understood states that can be clearly attributed to meson nonets, there are many candidates which could have an exotic nature instead. Such exotic particles e.g. glueballs, hybrids and tetraquarks can be favorably studied in clean, gluon rich environments. The BE-SIII experiment, which is in operation at the BEPCII electron-positron collider in Beijing since 2009, has collected world leading high statistic data samples in the charmonium region. This allows to study rare reactions that are considered to be suppressed. This offers unique possibilities to study exotic QCD states in the charmonium sector, but also the light meson spectrum which can be ac cessed via charmonium decays. Especially radiative J/ψ decays offer a gluon rich environment in which glueballs and hybrid states can be expected. Since these states are often hard to identify and disentangle, partial wave analysis are needed to determine the different contributions. [ABSTRACT FROM AUTHOR]

Abstract. We propose to study the structure of the enigmatic χc1(3872) axial vector meson through its γL*γ → χc1 (3872) transition form factor. We use our recently derived light-front wave function representation of the form factor for the lowest cc¯ Fock-state. We found that the reduced width of the state is well within the current experimental bound recently published by the Belle collaboration. This strongly suggests a crucial role of the cc¯ Fock-state in the photon-induced production. Our predictions for the Q2 dependence can be tested by future single tagged e+e− experiments, giving further insights into the short-distance structure of this meson. [ABSTRACT FROM AUTHOR]

Abstract. We investigate the dependence of both light and heavy quark masses on the properties of low-lying charmed mesons within the framework of one-loop HHX PT. Determination of the low energy constants is accomplished through an analysis of lattice data obtained from various Lattice Quantum Chro-modynamics (LQCD) simulations. Model selection tools are employed to identify the pertinent parameters needed to achieve higher precision alignment with the data. Our study extends to the analysis of HSC energy levels for DK scattering in I = 0, considering different boosts and two pion masses. A comprehensive global fit is performed, incorporating HSC energy levels along with those from DK and D* K scattering obtained from RQCD and Prelovsek et al. Finally, we extract the dependence of D*s0(2317) and Ds1(2460) resonances on the pion mass. [ABSTRACT FROM AUTHOR]

The so-called hadronization is a non-perturbative QCD phenomenon corresponding to the formation of colourless hadrons from coloured quark con stituents. The hadron formation in point-like e+e− collisions can be described by string models. According to the Lund model, the qq¯ pair production in the scattering is followed by a shower of light partons produced via multiple colour-string breaking, which produce colour singlets in the final states. The probability to obtain a hadron of a given species carrying a certain momentum fraction of the original quark is quantified by the fragmentation functions. They are assumed universal and usually constrained from e+ e− and e−p collisions, and they successfully describe the production of mesons in e+e− and pp colli sions at the colliders. However, recent measurements of pp collision data from the LHC showed a surprising relative enhancement of baryon production com pared to mesons, and model predictions based on string fragmentation do not describe the data. In this talk, an overview of the most recent experimental re sults of hadron production cross section in pp collisions at the LHC compared with e+e− results will be provided. A comparison with novel theoretical models implementing hadronization mechanisms different from the Lund string frag mentation will be also discussed, as well as experimental results obtained in larger systems, like p–Pb and Pb–Pb collisions. [ABSTRACT FROM AUTHOR]

Abstract. We show that the currently available data are consistent with Y(4230) being a D1D¯ hadronic molecule. By a simultaneous fit to data from e+e−→ D0D*−π+, J/ψπ+π−, J/ψK+K−, hcπ+π−, J/ψη, χc0ω, χc1(3872)γ and µ+µ−, we demonstrate that this single state can explain the experimental signals in the mass range from 4.2 to 4.35 GeV. [ABSTRACT FROM AUTHOR]

To study the internal structure of the exotic hadron X(3872), considering the coupled-channel potential between quarks and hadrons is necessary because X(3872) is regarded as a mixture state of cc¯ and D0D¯*0. In this work, we construct the hadron-hadron potentials coupled to the quark channel and study the properties of the D0D¯*0 potentials for X(3872). In particular, we compare various local approximations by focusing on the scattering phase shifts. [ABSTRACT FROM AUTHOR]

Abstract. Since its first detection, the interesting properties of the Tcc(3875)+ have made it to be one of the most prominent tetraquark-like states up to date. In this work we present a joint analysis of the T+cc and its charge-conjugated partner in a dense nuclear medium. We start by considering both states as purely isoscalar D*D and D¯*D¯S -wave bound states, respectively. We use previous results for the in-medium D, D¯*D¯, D* and D* spectral functions to determine the modified two-meson amplitudes. We find important changes in the in-medium mass and width of both tetraquark-like resonances, which become more visible when increasing the nuclear density and molecular probabilities. The experimental confirmation of the found distinctive patterns will support the existence of molecular components in the T+cc and T-c¯c¯ wave functions. [ABSTRACT FROM AUTHOR]

Abstract. We briefly review recent developments in the study of the quantum nature of flavor mixing; in particular, the attention will be devoted to neutrino and neutral meson oscillations. We employ Leggett-Garg type inequalities and no-signaling-in-time conditions to probe the intrinsic quantumness of such a physical manifestation, showing how the analysis is not affected by the wave-packet spreading (for neutrinos) and the intrinsic particle instability (for mesons). [ABSTRACT FROM AUTHOR]

Abstract. One of the prime goals of the COMPASS experiment at CERN is the study of the light meson spectrum, with a particular emphasis on the search for exotic states. The focus of this paper is on signals of the lightest hybrid can didate π1(1600) with spin-exotic quantum numbers JPC= 1−+ in several decay channels such as π−π+π−, rwπ−, ωπ−π0, π−π+π−η, and KSKSπ. In addition, we highlight new results for the K−π+π− final state, which indicate a supernumerary state with respect to the constituent quark model with JP = 0−. [ABSTRACT FROM AUTHOR]

Abstract. Light-by-Light scattering involves the interaction of two strong elec tromagnetic fields, resulting in the emission of two photons. In the next years, the ALICE 3 experiment is going to measure photons in the transverse mo mentum range pt= 1 - 50 MeV and 100 - 5000 MeV, which have not been investigated so far. Moving to a lower range of pt imposes a consideration of low-energy meson resonances which decay into two-photon channel. Further more, experimental possibilities to investigate the VDM-Regge mechanism are discussed. The role of the vertical background in light-by-light scattering mea surements is also shown. [ABSTRACT FROM AUTHOR]

Glueballs remain an experimentally undiscovered prediction of QCD. Lattice QCD predicts a spectrum of glueballs, with the tensor (JPC= 2++) glueball being the second lightest, behind the scalar glueball. From an effective hadronic model based on spontaneous and explicit chiral symmetry breaking, we compute decay ratios of the tensor glueball into various meson decay chan nels. We find the tensor glueball to primarily decay into 2 vector mesons, dom inated by ρρ and K* K*. These results are compared to experimental data of decay rates of spin 2 mesons. Based on this comparison we make statements on the eligibility of these mesons as potential tensor glueball candidates. [ABSTRACT FROM AUTHOR]

This talk is on a refined investigation on light flavor meson-baryon scatterings, using a dynamical coupled-channel approach, i.e. the Jülich-Bonn model. The previous channel space of πN, πΔ, σN, ρN, ηN, KΛ and Kσ is extended by adding the ωN final state. The spectra of N* and Δ resonances are extracted, based on the result of a global fit to a worldwide collection of data, in the energy region from the πN threshold to center-of-mass energy z = 2.3 GeV (approximately 300 parameters against 9000 data points). A negative value of the ωN elastic spin-averaged scattering length has been extracted. [ABSTRACT FROM AUTHOR]

In this talk, we present successful aspects of the tetraquark mixing model for the two light-meson nonets in the JPC= 0++ channel, the light nonet [a0(980), K*0(700), ƒ0(500), ƒ0(980)] and the heavy nonet [a0(1450), K0*(1430), ƒ0(1370), ƒ0(1500)]. In particular, we focus on how their experimental partial decay widths extracted from Particle Data Group (PDG) can support this mix ing model. Currently, the experimental data exhibit an unnatural tendency that partial widths of the light nonet are consistently larger than those of the heavy nonet. This unnatural tendency can be explained if the coupling into two pseudoscalar mesons is enhanced in the light nonet and suppressed in the heavy nonet as predicted by the tetraquark mixing model. Therefore, this could be strong evidence to support for the tetraquark mixing model. [ABSTRACT FROM AUTHOR]

In this contribution I briefly review the dynamics of strange mesons and baryons with dense nuclear matter, paying a special attention to their pres ence in the inner core of neutron stars and the consequences for the structure of these compact stars. [ABSTRACT FROM AUTHOR]

At the precision frontier of particle physics, light mesons decays play important roles in understanding strong interactions, quark Model, CP violations, and so on. They provide valuable laboratories for the testing Chiral Perturbative Theory predictions, studying the EM form factors and fundamen tal sysmmetries, and last but not least, probing new physics beyond the Standard Model. In this talk, we present the new results from BESIII about the η′ and η decays based on large J/ψ datasets. [ABSTRACT FROM AUTHOR]

The GlueX experiment at Jefferson Lab (Newport News, VA USA) is designed to explore the spectrum of mesons up to about 3 GeV. We present results on the production of light-quark resonances with linearly polarized photons. These results enhance our understanding of photoproduction mechanisms, which is valuable in subsequent searches for exotic hybrid mesons. Measurements of the J/ψ photoproduction cross section at threshold are also presented. [ABSTRACT FROM AUTHOR]

The BGOOD photoproduction experiment accesses forward meson angles and low momentum exchange kinematics in the uds sector, which may be sensitive to molecular-like hadron structure. Recent results are presented, including strangeness photoproduction at forward meson angles, and π0π0 co herent photoproduction off the deuteron. [ABSTRACT FROM AUTHOR]

We review results from the Jefferson Laboratory (JLab) program with the 12 GeV Upgrade of the CEBAF accelerator, with a particular emphasis on processes involving mesons. We include associated efforts in theory and phenomenology. We also discuss expected results from future analyses and data taking, including new instrumentation, in particular SoLID and the planned 22 GeV Upgrade of CEBAF. [ABSTRACT FROM AUTHOR]

The phenomenon of strangeness enhancement, originally proposed as a signature of quark-gluon plasma formation, has received considerable new interest following recent observations in small collision systems. LHCb is uniquely well suited to study such effects in the heavy quark sector, down to very low transverse momentum. Here we will present new LHCb results on the production rates of B0s relative to B0 mesons versus multiplicity in pp collisions. Potential implications for the hadronization mechanism of heavy quarks and our understanding of the factorization of fragmentation functions will be discussed. [ABSTRACT FROM AUTHOR]

Electric dipole moments (EDMs) of fundamental particles violate time invariance and the combined symmetry of charge and parity (CP). The existence of a large muon EDM (muEDM) is made plausible by tensions with Standard Model predictions for semileptonic decays of heavy meson measured at LHCb, BaBar, and Belle, as well as the muon's anomalous magnetic moment (AMM). A discovery of the muEDM would manifest CP and lepton flavor universality (LFU) violation, revealing physics beyond the SM (BSM). The most sensitive muEDM search to date provides an upper limit of 1.8 × 10-19 e·cm (CL 95%), extracted from high-precision data collected to measure the muon AMM. At the Paul Scherrer Institute, we are setting up a dedicated search for the muEDM using, for the first time, the frozen-spin technique to target an ultimate sensitivity better than 6 × 10-23 e·cm. This novel technique increases the sensitivity to EDM-induced spin precession by cancelling the AMM-induced precession with the application of a precisely tuned electric field perpendicular to the muon momentum and the magnetic field. In this configuration, the dominant source of precession is the EDM coupling to the large relativistic electric field in the muon rest frame, generated by its motion in a strong 3 T uniform magnetic field. In a precursor experiment, we will apply the frozen-spin technique in a compact solenoid demonstrating a sensitivity of better than 3 × 10-21 e·cm, probing uncharted and otherwise inaccessible territory in BSM theories. [ABSTRACT FROM AUTHOR]

We discuss the recent progress made in using bottom-up holographic QCD models in calculating hadronic contributions to the anomalous magnetic moment of the muon, in particular the hadronic light-bylight scattering contribution, where holographic QCD naturally satisfies the Melnikov-Vainshtein constraint by an infinite series of axial vector meson contributions. [ABSTRACT FROM AUTHOR]

The high intensity proton accelerator complex (HIPA) at the Paul Scherrer Institute (PSI) delivers a 590 MeV CW proton beam with currents up to 2.4 mA (1.4 MW). Besides two spallation targets for thermal/cold neutrons (SINQ) and for ultracold neutrons (UCN), the beam feeds two meson production targets Target M and Target E. The targets consist of graphite wheels of effective thickness 5 mm (M) and 40/60 mm (E). The target stations M and E are of quite different design; however, both of them rotate at 1 Hz to dissipate the heat (20 kW/mA for the 40 mm target E) efficiently. Recent progress was made by a new type of bearings and a new target geometry able to increase the rate of surface muons by up to 50 %. This is also foreseen for the upgrade of the target station M within the High Intensity Muon Beam (HIMB) initiative aiming to increase the surface muons available for experiment by two orders of magnitude. HIMB is part of IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technology), an application for the Swiss Roadmap of Research Infrastructure. [ABSTRACT FROM AUTHOR]

The Electron-Ion Collider (EIC) is a future collider planned to be built at BNL in about a decade. It will provide physicists with high luminosity and highly polarized beams with a wide range of nuclei species at different energies, covering an extensive kinematic range. The EIC physics goals include measuring the Generalized Parton Distribution (GPD) from Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) experiments, performing precision 3D imaging of the nuclei structure, studying color confinement and hadronization mechanisms, and understanding the spin structure of the proton. In order to meet the physics goals of EIC, a highresolution electromagnetic calorimeter (EMCAL) is required to measure electrons and photons and to achieve good particle identification. We propose to develop a tungsten/shashlik (W/shashlik) EMCAL with better readout configuration to achieve better energy and position resolution. In this work, we will present the GEANT4 detector simulation results ofWand Pb shashlik EMCAL to study π0 merging probability as a function of π0 energy and the performance of position and energy resolutions of the EMCAL for ECCE design. [ABSTRACT FROM AUTHOR]

The ALICE Collaboration has observed that the ratio of strange to non-strange hadron yields increases strongly with multiplicity in small collision systems at LHC energies. The origin of this effect is still not fully understood. Models need to incorporate final-state interactions to accommodate the new ALICE results, and require new measurements to discriminate between the various phenomenological descriptions. Two different ALICE studies, aiming to further elucidate the underlying mechanisms of strangeness production in high-multiplicity proton–proton (pp) collisions at √S = 13 s = 13 TeV, are presented in this proceeding. First, the production of η and π0 are studied as a function of multiplicity, combining several analysis techniques, allowing a measurement for the neutral meson production over a vast transverse momentum (pT) range. This is followed by a measurement of π, K, ϕ, and Ξ as a function of the unweighed transverse spherocity SOPT=1 S O p T = 1 , an event-shape observable which allows us to explore particle production in azimuthal topologies dominated by either hard or soft QCD processes. The results are compared to predictions from PYTHIA and EPOS-LHC. [ABSTRACT FROM AUTHOR]

We present a new model for the description of heavy-flavor hadronization in relativistic heavy-ion collisions. We explore its effect on the charmed hadron yields and kinematic distributions once the latter is applied at the end of transport calculations used to simulate the propagation of heavy quarks in the deconfined fireball produced in the collision. The model is based on the formation of color-singlet clusters through the recombination of charm quarks with light antiquarks or diquarks from the same fluid cell. This local mechanism of color neutralization leads to a strong space-momentum correlation, which provides a substantial enhancement of charmed baryon production and of the collective flow of all charmed hadrons. [ABSTRACT FROM AUTHOR]

The statistical hadronization model ThermalFist was applied to numerous hadron yields measured in p+p collisions at √S = 8.8 s = 8.8 , 12.3 and 17.3 GeV, including recently published yields of ϕ-mesons, measured by the NA61/SHINE Collaboration. We consistently used the energy-dependent widths of Breit-Wigner mass distributions of hadronic resonances, as this approach was generally found to provide better agreement with experimental data. The well-established experimental ϕ meson yields are consequently accounted for (although neglecting this particle was found to improve the fit quality). The canonical treatment of particles with open strangeness with the grand canonical approach for non-strange particles gave a moderately reasonable agreement with the measured yields, only when the volume of strange particles was allowed to vary freely. In all the studied cases this volume is found to be greater than the canonical one. [ABSTRACT FROM AUTHOR]

We study ϕ meson production in heavy-ion collisions from subthreshold energies of 1.23 A GeV up to RHIC energies within the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach where novel production channels for ϕ mesons based on a coupled channel T-matrix approach are implemented along with the collisional broadening of the ϕ meson spectral width in medium. Since ϕ meson production is closely related to the production of kaons and antikaons, antikaon properties are described via the self-consistent coupled-channel unitarized scheme within a SU(3) chiral Lagrangian (G-matrix) which incorporates explicitly the s− and p− waves of the kaon-nucleon interaction, while the in-medium modifications of kaons are accounted for via a kaon-nuclear potential, which is assumed to be proportional to the local baryon density. [ABSTRACT FROM AUTHOR]

In this contribution, the measurement of the centrality dependence of the nuclear modification factor (RAA) of non-prompt D0 meson in Pb-Pb collisions at √SNN = 5.02 TeV s NN = 5.02  TeV is presented. This measurement provides important constraints to the in-medium mass dependence of energy loss and hadroniza-tion of the beauty quark. In addition, the first measurements of non-prompt Ds+ Ds + meson production in central and semi-central Pb-Pb collisions at √SNN = 5.02 TeV s NN = 5.02  TeV are discussed. The non-prompt Ds+ Ds + meson measurements provide further information on the production and hadronization of Bs0 Bs 0 mesons. Finally, the first measurement of non-prompt D-meson elliptic flow in Pb-Pb collisions at √SNN = 5.02 TeV s NN = 5.02  TeV is shown. This measurement can help to investigate the degree of thermalization of beauty quarks in the hot and dense QCD medium. [ABSTRACT FROM AUTHOR]

Global spin alignment is a preferential alignment of a particle's spin along the orbital angular momentum produced in heavy-ion collisions. The global spin alignment of vector mesons (JP = 1−) ϕ and K*0 may be sensitive to the vorticity in the medium and hadronization mechanisms. The second phase of RHIC Beam Energy Scan (BES-II) program provides higher statistics data sets for Au+Au collisions at √SNN = 7.7 - 19.6 GeV s NN = 7.7 − 19.6  GeV . From this data, we can make high precision measurements of ϕ and K*0 global spin alignment, allowing for more differential studies not possible with the BES-I data. We can also compare global spin alignment between ϕ and K*0, where the lifetime of ϕ is roughly ten times larger than that of K*0 and the latter is more sensitive to hadronic rescattering. We report high precision measurements for the global spin alignment of ϕ at √SNN = 19.6 GeV s NN = 19.6  GeV from BES-II. [ABSTRACT FROM AUTHOR]

Quarkonia have been long proposed as the golden probes to study quark-gluon plasma (QGP) in heavy-ion collisions. In this presentation, we present the second- and third-order Fourier coefficients, v2 and v3, for prompt and nonprompt J/ψ mesons in PbPb collisions as functions transverse momentum (pT) and PbPb collision centrality. Also, we report the first measurements of v2 and v3 for the prompt ψ(2S) mesons in PbPb collisions. The results provide v2 and v3 values over the wide studied kinematics regions of transverse momentum and collision centrality. [ABSTRACT FROM AUTHOR]