We present an analytically solvable model based on the blast-wave picture of heavy-ion collisions with flow-momentum correspondence. It can describe the key features of spin polarizations in heavy-ion collisions. With the analytical solution, we can clearly show that the spin polarization with respect to the reaction plane is governed by the directed flow, while the spin polarization along the...
Using continuum Schwinger function methods, a coherent set of predictions for proton, Λ and Σ0 baryons is delivered - both helicity dependent and unpolarised. The analysis reveals impacts of diquark correlations and SU(3)-flavour symmetry breaking, some of which are significant. For instance, were it not for the presence of axialvector diquarks in the Σ0, the strange quark could carry none of...
Neutron beams generated at the China Spallation Neutron Source (CSNS) are dedicated for material characterization through scattering process. Polarization can be introduced before and after the neutron scatter with the sample so that neutron magnetic dipole interaction with local magnetization can be observed, know as polarized neutron scattering. The polarized neutron can be expanded to...
At BESIII, the electromagnetic form factors (EMFFs) and the pair production cross sections of various baryons have been studied. The proton EMFF ratio |GE/GM| is determined precisely and line-shape of |GE| is obtained for the first time. The recent results of neutron EMFFs at BESIII show great improvement comparing with previous experiments. Cross sections of various baryon pairs (Lambda,...
With the largest datasets on $e^+ e^-$ annihilation at the $J/\psi$ and $\psi(3686)$ resonances collected at the BESIII experiment, multi-dimensional analyses making use of spin polarization and entanglement can shed new light on the production and decay properties of hyperon-antihyperon pairs. In a series of recent studies performed at BESIII, significant transverse spin polarization of the...
The Solenoidal Large Intensity Device (SoLID) is an advanced spectrometer under development in Hall A at Jefferson Lab. Designed for high-luminosity operation (10³⁷–10³⁹ cm⁻²s⁻¹) with both polarized (NH3 and 3He) and unpolarized hydrogen and deuterium targets, SoLID features large acceptance and full azimuthal coverage. It will fully exploit the capabilities of the 12 GeV CEBAF upgrade and is...
The form factors are important physical quantities that characterize
the internal structure of a nucleon. In the classical picture, it
corresponds to the Fourier transform of the nucleon's three-dimensional
density distribution. Among them, the electromagnetic form factors are
the most well-known, with thousands of high-precision experimental data
accumulated to date. The axial form...
A better theoretical understanding of the quantum mechanical processes in spin filter for the separation of metastable hydrogen atoms in individual hyperfine substates enables a number of new applications. For example, it is now possible to build a new generation of Lamb-shift polarimeter that can separate not only α but also the β states with $m_J = -1/2$. This opens up completely new...
We report on a global fit of neutral-current elastic (NCE) neutrino-scattering data and parity-violating electron-scattering (PVES) data with the goal of determining the strange quark contribution to the vector and axial form factors of the proton. Knowledge of the strangeness contribution to the axial form factor, $G_A^s(Q^2)$, at low $Q^2$ will reveal the strange quark contribution to the...
The violation of the charge-parity (CP) transformation symmetry, which although has been observed in plenty of pure meson decay processes, was only confirmed just very recently by the LHCb collaboration in the four-body decay of the heavy baryon $\Lambda_b^0$, $\Lambda_b^0\to p K^- \pi^+ \pi ^-$, through a comparison of the decay branching ratio with that of the CP-conjugate process. However,...
Abstract: Fragmentation Function (FF) plays a crucial role in describing the hadronization process. We report the measurements of normalized differential cross sections of inclusive pi0 and Ks production as a function of hadron momentum at six energy points with q^2 transfer from 5 to 13 GeV^2 at BESIII. The results with a relative hadron energy coverage from 0.1 to 0.9 significantly deviate...
Particles of non-zero spin produced in non-central heavy-ion collisions are expected to be polarized along the direction perpendicular to the reaction plane because of their spin-orbit interactions in the produced matter. In this talk, I will show that the hypertriton, which is the lightest hypernucleus, is also polarized in these collisions. I will demonstrate that the polarization and decay...
I will present an overview of our activities on the study of the three-nucleon force using a polarized deuteron beam and a polarized proton target at RIKEN, with particular focus on the polarized proton target. We have developed the target system based on Dynamic Nuclear Polarization with photoexcited triplet electrons (Triplet-DNP), operating at 0.4 T and room temperature. Low-field operation...
We present the first systematic study of the relativistic intrinsic spin structure of a general spin-$1/2$ hadron in position space. We show in particular that the slope of the nucleon axial form factor $G_A^Z(Q^2)$ in the forward limit, conventionally denoted as $R^2_A \equiv -\frac{6}{G_A^Z(0) } \frac{ \text{d} G_A^Z(Q^2) }{\text{d} Q^2} \Big|_{Q^2=0} $ in the literature, does not faithfully...
Quarkonium production and polarization serves as a vital testing ground for quantum chromodynamics (QCD), offering critical insights into both perturbative and nonperturbative dynamics. In the nonrelativistic QCD (NRQCD) factorization framework, inclusive production cross sections of quarkonia are expressed as products of perturbatively calculable short-distance coefficients (SDCs) and...
Spin correlations between particles produced at colliders provide valuable insights for quantum information studies. While traditional studies of quantum information at colliders are typically limited to massive particles with perturbative decay, we propose an innovative method to explore the Bell inequality in massless quark pair systems by analyzing the azimuthal correlations in $\pi^+\pi^-$...
For the last two decades, the PHENIX collaboration at Brookhaven National Laboratory has explored nuclear spin physics by leveraging the Relativistic Heavy Ion Collider’s unique ability to collide transversely or longitudinally polarized protons. Eta meson production is a particularly practical channel at PHENIX as their detection is possible through diphoton decays in both the central and...
we propose a novel approach to measure the final-state proton polarization in large-acceptance collider experiments. Using existing tracking devices and supporting structure material, general-purpose spectrometers can be utilized as a large-acceptance polarimeter without hardware upgrade. This approach is tested at BESIII, and can be applied at nearly all major facilities, such as Belle-II,...
We present lattice QCD computations addressing crucial aspects of meson internal structure through electromagnetic form factors (EMFFs) and generalized parton distributions (GPDs). Utilizing physical masses and fine lattices, we calculate pion and kaon EMFFs at momentum transfers up to approximately 10 and 28 GeV$^2$, respectively, achieving good agreement with available experimental data at...
Supposing there exists an effective charge which defines an evolution scheme for both unpolarised and polarised parton distribution functions (DFs) that is all-orders exact and using Ansätze for hadron-scale proton polarised valence quark DFs, constrained by flavour-separated axial charges and insights from perturbative quantum chromodynamics, predictions are delivered for all proton polarised...
In proton-proton ($pp$) collisions involving a transversely polarized proton beam and an unpolarized proton beam, a left-right or azimuthal asymmetry is observed in the distribution of final-state scattered particles. The experimentally measurable quantity is known as the Transverse Single Spin Asymmetry ($A_N$). This asymmetry arises from fundamental Transverse Momentum Dependent (TMD)...
We propose a novel series of methods to investigate light-quark dipole interactions at colliders. These methods include: (1) utilizing the azimuthal asymmetry of a collinear dihadron pair $(h_1h_2)$ produced in association with an additional hadron $h'$ at lepton colliders; (2) examining the azimuthal asymmetries of a collinear dihadron in semi-inclusive deep inelastic lepton scattering off an...
Measurements by the STAR Collaboration of global Λ hyperon polarization and 𝜙,𝐾∗0 meson spin alignment in heavy-ion collisions [1, 2] have confirmed the global polarization of quark matter [3, 4] and indicated strong quark–antiquark spin correlations. Quark spin correlations have emerged as a new frontier and a rapidly developing research hotspot.
In Ref. [5], we propose a systematic method...
Nuclear spin polarization has important applications across various fields, including physics and medicine. It also offers several advantages, such as cross-section enhancement, in the five-nucleon fusion reactions, namely the D-T and D-$^3$He reactions. This work presents a theoretical study of spin dynamics in the hyperfine regime for selected atomic and molecular systems and explores...
The unpolarized and polarized gluon parton distribution functions are calculated in lattice QCD using the Large-Momentum Effective Theory(LaMET) method. The calculations are carried out at three different lattice spacings and pion mass around 300MeV. The results are extrapolated to the continuum and infinite momentum limits. The unpolarized gluon PDF is consistent with the global fit of CT18NNLO.
We present the first calculation of quantum electrodynamics (QED) nuclear medium effects under the experimental conditions of future Electron-Ion Collider (EIC) experiments. While prior studies have predominantly focused on elastic scattering, our investigation extends to the more complex scenarios of inelastic processes within a nuclear medium. For lead nuclei, our findings suggest that the...
This talk will present recent results on the determination of transverse momentum distributions by the MAP collaboration, with a particular emphasis on the flavor dependence of unpolarized TMDs, on the helicity TMD, and on machine-learning methods."
The dominance of matter over antimatter in the universe remains one of the key unresolved questions in modern physics. According to the Sakharov conditions, this asymmetry requires a violation of CP symmetry. While the Standard Model includes CP-violating effects, they are insufficient to account for the observed imbalance. A promising candidate for additional sources of CP violation is the...
The development of polarized neutron technology is pivotal for advancing studies in material science and fundamental physics, particularly in probing magnetic structures and symmetry violations. At the China Spallation Neutron Source (CSNS), significant progress has been made in the design and implementation of polarized 3He neutron spin filters (NSFs) based on spin-exchange optical pumping...
We present a comprehensive investigation into the anomalous magnetic dipole moment ($a_\tau$) and electric dipole moment ($d_\tau$) of the $\tau$ lepton using the $\gamma\gamma \to \tau^+\tau^-$ process at future lepton colliders, with the Super Tau-Charm Facility serving as a benchmark. By employing transverse-momentum-dependent factorization, we introduce novel observables derived from...
We report recent advancements in understanding nucleon structure within the Basis Light-Front Quantization (BLFQ) framework—a fully relativistic, nonperturbative approach to solving quantum field theories. Starting with the leading Fock sector $|qqq\rangle$ and an effective light-front Hamiltonian incorporating confinement and one-gluon exchange, BLFQ has successfully described key nucleon...
We use the ensemble C24P29 provided by the CLQCD collaboration, insert the topological current using the proton external state of the momentum smear under the Coulomb gauge of the 5-HYP smear, extract the matrix elements to calculate the gluon helicity under lattice QCD, and the calculation proves that different components of the topological currents ($K^z$ and $K^t$) can be used to give...
After the conceptual improvements to transverse momentum dependent (TMD) extractions of a flavour dependent ansatz as well as a more robust propagation of uncertainties onto the resulting TMD functions in ART23, the following work ART25 is a state of the art determination of the unpolarised TMD parton distribution functions and -fragmentation functions such as the Collins-Soper kernel via a...
The PREFER (Polarization REsearch for Fusion Experiments and Reactors) collaboration aims to address the know-hows in different fields and techniques to the challenging bet on energy production by nuclear fusion with polarized fuel. The collaboration involves different institutions and researchers, sharing skills and peculiar abilities, having then possibilities to...
We propose a ``blending" algorithm that projects the all-to-all fermion propagator onto spatial low-frequency modes (LFM) combined with a stochastic estimate of spatial high-frequency modes (SHFM) at each time slice.
This approach enables the calculation of arbitrary-point correlation functions for arbitrary hadron states in strongly interacting quantum field theories (QFT) with fermions,...
We present a lattice QCD calculation for the leading-twist Light-cone Distribution Amplitudes (LCDAs) of the Lambda and Proton, within the framework of Large-momentum Effective Theory (LaMET). The numerical computation employs CLQCD ensembles with stout smeared clover fermions and a Symanzik gauge action. In order to obtain reliable results in both perturbative and non-perturbative regions, we...
The observation of hyperon global polarization along the system's angular momentum has revealed the existence of large vorticities in the medium created by heavy-ion collisions. In this talk, we present measurements of global polarization for $\Lambda$, $\Xi$, and $\Omega$ hyperons in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 9.2, 11.5, 14.6, 17.3, 19.6, and 27 GeV, based on high-statistics...
The total cross section of the interaction of transversaly polarized ($P_y$) proton ($^3$He or deuteron) with the tenzor polarized ($P_{xz}$) deuteron constitues a null-test signal of time-reversal invariance violation under parity conservation (TVPC) in such processes (see Ref. [1] and references therein). This result follows from the optical theorem providing this signal for such...
Proton-boron (p-¹¹B) fusion is widely recognized as a promising candidate for future clean energy due to its advantages of abundant fuel, inherent safety, and minimal neutron emissions. However, the practical realization of p-¹¹B fusion faces significant challenges, primarily due to its stringent ignition conditions and relatively low reaction cross-section. Recently, spin polarization has...
Time reversal symmetry has long been a subject of interest from pre-modern physics time, since it implies the reversibility of motion. In the K^+→π^0 μ^+ ν (K_μ3) decay, the transverse muon polarization (P_T) is defined as the polarization component perpendicular to the decay plane. A non-vanishing value of P_T provides clear evidence for T-violation under the condition that spurious effects...
Using continuum Schwinger function methods and the Drell-Levy-Yan relation, this work provides a unified description for pion and kaon distribution functions and fragmentation functions (FFs). After evolution to higher scale, the obtained FFs conform with a range of physical expectations for FF behaviour on the endpoint domains, such as that nonsignlet FFs vanish at z=0 and singlet FFs diverge...
In this talk, we have implemented the quantum kinetic theory combined the relativistic hydrodynamics to study the spin polarization of Lambda hyperons in the relativistic AA and pA collisions. The global polarization can be well described by the current theoretical frameworks. The local polarization in low energies AA collisions and pA collisions cannot be fully understood.
In this talk, I will present the first extraction of TMD helicity distributions, by analyzing double spin asymmetry data from SIDIS.
In the selection of fusion fuels, proton and boron-11 as an ideal choice for commercialization due to its abundant raw materials and the absence of neutron production in the reaction. Compared with other fusion fuels, the proton-boron reaction has a smaller cross-section and requires a higher ignition temperature. To address or mitigate the impact of these difficulties, it is necessary to...
In this talk, we will demonstrate how quantum kinetic theory determines spin effects in global equilibrium. We show that by generalizing from constant to varying electromagnetic fields, previously indeterminate spin effects induced by vorticity and electromagnetic fields can now be further pinned down.
We present the first global analysis of fragmentation functions (FFs) for light charged hadrons ($\pi^\pm, K^\pm$) at full next-to-next-to-leading order in QCD, incorporating world data from both single-inclusive electron-positron annihilation and semi-inclusive deep-inelastic scattering. The collinear factorization has been tested with low-momentum-transfer data and has demonstrated success...
The CP violation beyond the standard model is not only physically interesting on its own, but also a key for understanding the baryon asymmetry in the current universe. In a low energy region, instead of directly probing it, many efforts to search the violation of time-reversal symmetry(T-violation) continue in various physics systems with high sensitivity. Among those, neutron-induced...
We present the global analysis of Sivers functions, worm-gear distribution functions, transversity distribution functions, and Collins fragmentation functions within the transverse momentum dependent factorization. This analysis encompasses the latest data from SIDIS, DY, and W±/Z-boson production processes. In addition, based on a combined analysis of world data and simulated data, we...
Electric Dipole Moments (EDMs) are very sensitive probes of physics beyond the Standard Model (SM). The JEDI collaboration aims to measure the EDMs of charged particles making use of polarized beams in a storage ring. Such a precision experiment requires the maximization of the Spin Coherence Time (SCT). To identify the working conditions that maximize the SCT, the spin tune of the single...
In this work, we investigate the nuclear modification effects in transverse momentum dependent
(TMD) observables by implementing a nuclear covariance matrix in the treatment of theoretical uncertainties. Global QCD analysis is performed with the aforementioned nuclear covariance matrix to verify its equivalence with the traditional approach of including a nuclear correction parameter. The...
Spin is a fundamental property of particles and plays a crucial role in particle structure and interactions. In a polarized ion beam, the spins of ions favor a particular direction, which is not only crucial for spin physics research but also beneficial for cutting-edge physics experiments that require high precision. For producing intense polarized ion beams, a Spin Polarized Ion Source...
Deeply Virtual Compton Scattering (DVCS) and exclusive $\pi^0$ electroproduction provide experimental access to Generalized Parton Distributions (GPDs). In these channels, the measured cross sections are expressed in terms of Compton Form Factors (CFFs), which correspond to the first moments of the underlying GPDs. From September 2023 to May 2024, Jefferson Lab Hall C conducted experiment...
The Electron-Ion Collider in China (EicC) is a proposed high-intensity facility designed to explore the partonic structure of nucleons and nuclei, particularly in the sea quark region, with unprecedented precision. Its physics program aims to uncover the origin of nucleon mass and spin, image the three-dimensional landscape of partons, study quark-gluon dynamics in nuclei, and search for...
The polarized transverse-mementum-dependent fragmentation function (TMD FF) $D_{1T}^\perp$ have attracted lots of attention from both experiment and theory communities. Starting from a isospin symmetric parametrization for $D_{1T}^\perp$, we have studied transverse polarizations of $\Lambda$ in various collisions. Recently we focus on nuclear collisions and study the QGP medium effects via QCD...
The contribution of parton orbital motion to the nucleon spin structure is encoded in transverse-momentum dependent distributions (TMDs) and generalized parton distributions (GPDs). These distributions are primarily accessed through lepton-induced processes such as semi-inclusive deep-inelastic scattering (SIDIS) and Deeply Virtual Compton Scattering (DVCS). As a complementary approach,...
The study of the spin effects and polarization phenomena in hadronic reactions is the traditional scientific direction of JINR. Nowadays Spin Physics Detector [1] at NICA as well as new spin projects at the fixed targets [2,3] at Nuclotron are in preparation. This research program requires the development of high intensity polarized beams, polarized targets, beam and focal polarimetry,...
We present a comparative study of Compton Form Factor (CFF) extraction using pseudodata derived from Deeply Virtual Compton Scattering (DVCS) experiments at Jefferson Lab. The analysis is based on the twist-two formalism of Belitsky, Kirchner, and Müller, incorporating a minimally biased fitting strategy inspired by local fits to reduce model dependence. Two machine learning approaches are...
We present an analysis of lepton-jet azimuthal decorrelation in deep-inelastic scattering (DIS) at next-to-next-to-next-to-leading logarithmic (N$^{3}$LL) accuracy, combined with fixed-order corrections at $\mathcal{O}(\alpha_s^2)$. In this study, jets are defined in the lab frame using the anti-$k_T$ clustering algorithm and the winner-take-all recombination scheme. The N$^{3}$LL resummation...
At the JINR accelerator complex, within the polarization research program of the NICA project, the high-intensity SPI source of polarized deuterons and protons and low-energy polarimeters are being developed for the SPI setup at the outlet and behind the 5 MeV/nucleon linear accelerator.
The status, upgrades of the above facilities, future prospects are presented.
[1] G.V. Trubnikov,...
Until 2023, a polarized H$^-$/D$^-$ ion source delivered pulsed negative ion beams for stripping injection into the COSY accelerator. Accurate and efficient measurement of the nuclear spin polarization directly behind the source is essential for precision experiments at COSY. A data acquisition system was developed to enable reliable, automated measurements with improved efficiency and to...
The deuteron-proton elastic scattering process is considered in the relativistic
expansion framework. Four reaction mechanisms are taken into account: one-nucleon-exchange,
single-scattering, double-scattering terms, and delta-isobar excitation in the intermediate state.
Each of these terms contributes into the reaction amplitude.
The model calculates the reaction amplitude, which makes...
We present two complementary advances toward precision QCD predictions for multi-jet processes at the LHC, both based on observables constructed with the Winner-Take-All (WTA) recombination scheme. First, we develop two generalizations of the transverse-momentum slicing variable $q_T$ applicable to jet final states, enabling a slicing approach for processes like $pp \to 2$ jets. A proof of...
Deeply virtual Compton scattering (DVCS) is established as the golden channel for accessing generalized parton distributions (GPDs), which encode the nucleon's three-dimensional structure and are crucial for understanding the origin of nucleon spin. In this talk, I will summarize recent theoretical advances in predicting the DVCS process to higher perturbative orders. These developments are...
LHC at CERN is the world's highest energy collider, but it cannot accelerate polarized protons like BNL's RHIC. The LHCspin project will install a polarized hydrogen gas target in one of the accelerator rings of the LHC and use a 7 TeV proton beam and the polarized target to advance research into nucleon spin structure. In the first step, the polarized gas target and a simple particle detector...
The principle of using multiple partial helical magnets to preserve the polarization of the proton beam during its acceleration was applied successfully to the alternating gradient synchrotron (AGS) which currently operates with two partial helical magnets. In this paper we further explore this idea by using four partial helical magnets placed symmetrically in the AGS ring. This provides many...
Exclusive heavy vector meson production is investigated in ep pp and pPb collisions employing GPD approach with GK model. Three sets gluon density are used to calculate exclusive heavy vetor meson production. The survival factors and equivalent photon approximation are applied to predict the exclusive heavy vector mesons photoproduction in proton-proton collisions. The GPD method prediction...
We propose a novel strategy to systematically isolate the nucleon’s intrinsic non-perturbative three-dimensional structure by employing 0-jettiness to suppress initial-state radiation in transverse momentum-dependent (TMD) observables. Applying this method to transverse single spin asymme tries (SSAs) in W$^\pm$ and Z$^0$ boson production at RHIC, we demonstrate a substantial enhancement of...
Recently COMPASS showed an interesting result on the d-quark Sivers TMD PDF via SIDIS process with muon beam and the polarized deuteron polarized target. It showed that the d-quark Sivers asymmetry had almost twice larger than u-quark at high-x region.
In order to understand the d-quark OAM contribution on the nucleon spin structure, further measurements via other processes like a...
Despite the successful description of global polarization of $\Lambda$ hyperons in heavy ion collisions through thermal voricity, the follow-up observations of local spin polarization and spin alignment of vector mesons further indicate the presence of additional mechanisms upon spin transport of quarks in the QCD medium. In high-energy nuclear collisions, the soft thermal gluons in the quark...
we explore the Bjorken $x$ weighted EEC in DIS from the TFR to CFR. In both regions, a factorization theorem can be derived with SCET, based on which the logarithms can be resummed to all orders in $\alpha_s$. The singular distributions can be derived from the factorized formula, which are compared against the full fixed-order QCD calculations up to NLO. Additionally, we present the...
The P2 experiment at Mainz Energy-Recovering Superconducting Accelerator (MESA) aims to measure the Weinberg angle with an uncertainty of 0.15%. This implies that the uncertainty of the beam polarization measurement must be less than 1%. To achieve this, a polarimetry chain with polarimeters operating at different energies and principles is being developed.
As a part of this polarimetry...
The energy-momentum tensor encodes the internal energy, spin, and stress distributions within hadrons, shedding new light on hadron structures and fundamental QCD problems such as confinement and the origin of hadron mass. In recent years, it has become possible to measure this quantity directly from experiments via generalized parton distributions, leading to growing interest in both...
In high-energy nuclear physics, spin plays a crucial role in the composition of matter and the interaction between particles. The Institute of Modern Physics, Chinese Academy of Sciences, plans to develop polarized beams and targets for spin-related studies at the High Intensity heavy-ion Accelerator Facility (HIAF). The target is mainly composed of an atomic beam source, a target chamber and...
The report describes the production of an internal polarized deuteron target for experiments at the VEPP-3 electron storage ring. A description of the measurement of the average target polarization during the experiments is given. The schemes of the system for tagging photons that caused reactions, as well as the system for registering reaction products are presented. The results of the...
We present an upgraded formula for Wigner function and spin polarization of fermions emitted by a relativistic fluid at local thermodynamic equilibrium at the freeze-out which improves the one obtained in literatures and used in numerical simulations of relativistic nuclear collisions. By using a
new expansion method applicable to freeze-out hypersurfaces with arbitrary geometry, we reproduce...
The generalized distribution amplitudes (GDAs) have attracted attention in recent years because of their relation with the energy momentum tensor (EMT) form factors (FFs). The GDAs can be experimentally accessed through the study of amplitudes in $\gamma^{\ast} \gamma \to M_1 M_2$ and $\gamma^{\ast} \to M_1 M_2 \gamma$, where $M_1M_2$ is a pseudoscalar meson pair such as $\pi \eta $ and...
In this work, we introduce a new jet observable, the one-point energy correlators (EC), designed to characterize the in-jet energy flow distribution by measuring energy deposition at a specific angle relative to the jet axis. Building upon the transverse momentum dependent physics, we aim for the EC to provide novel insights into jet substructure and offer a new approach to study TMD physics,...
This presentation will overview the study of polarized lepton beams in the context of resonant depolarization and longitudinal polarized colliding beams, for the 100km scale Circular Electron Positron Collider (CEPC), including design studies and R&D progress, as well as the potential of attaining longitudinal polarization at BEPCII.
Nuclotron Accelerator Complex gives the opportunity to study spin effects using polarized deuteron and proton beams from Source of Polarized Ion. Recent results on the spin effects in deuteron-proton and proton-proton elastic scattering sensitive to the short-range spin structure of the nucleon-nucleon correlations obtained at the internal target at Nuclotron are discussed.
The...
This presentation offers a unified set of results for the elastic electromagnetic and gravitational form factors of the pion, kaon, and nucleon, using continuum Schwinger function methods. A key feature of the study is the consistent treatment of dressed graviton–quark interactions, allowing seamless analysis across mesons and baryons. We find that the mass radii of pions and kaons are smaller...
Quarkonia production in high-energy proton-proton (pp) collisions serves as an important probe for studying quantum chromodynamics (QCD) in vacuum. Understanding the production mechanism of the J/$\psi$, a bound state of a charm and anticharm quark, is essential for constraining both perturbative and non-perturbative aspects of QCD calculations. The polarization of quarkonia in pp collisions...
We propose a novel method to probe the Collins effect, a key signature of the nucleon's 3D structure, using an intra-jet energy correlator. This new observable, based on the energy-weighted azimuthal distribution of hadrons within a jet, can be measured in transversely polarized proton-proton collisions at RHIC. The resulting $\sin(\phi_h - \phi_S)$ single-spin asymmetry provides a direct...
Over the past few decades, polarized electron beams have been actively used in various fields of physics. Mott, Moller, and Compton scattering methods are used to diagnose the polarization of such beams. We propose to use a different method. The high charge densities achieved in electron beams offer the possibility of measuring the polarization by scattering one electron beam off another....
Continuous wave Nuclear Magnetic Resonance (NMR) with constant current has been pivotal in solid-state polarized target experiments within Nuclear and High Energy Particle physics. Phase-sensitive detection using a Liverpool Q-meter is conventionally employed for monitoring polarization during scattering experiments. Yet, when operating outside of designed operational parameters, there are...
Baryon-antibaryon generalized distribution amplitudes (GDAs) give an access to timelike gravitational form factors (GFFs) which are complementary to the spacelike ones which can be deduced from the hadronic generalized parton distributions (GPDs) measured in deep exclusive electroproduction processes. They allow to probe the GFFs of unstable baryons in the baryon octet, since the second...
We initiate a systematic study of fragmentation energy correlators (FECs), which generalize traditional fragmentation functions and encode non-perturbative information about transverse dynamics in parton fragmentation processes.
We define boost-invariant, non-perturbative FECs and derive a corresponding collinear factorization formula. A spin decomposition of the FECs is carried out,...
As a key R&D item of polarized lepton beams for future colliders, a laser Compton polarimeter has been designed for the electron storage ring of BEPCII, reusing the X-ray beamline and experimental hutch of a dismantled wiggler source. This article will describe the design considerations of the Compton polarimeter, report the first phase beamline modification and preliminary beam commissioning...
We study the two-flavor Nambu-Jona-Lasinio model under the rotation and chiral chemical potential μ5. First, the influence of chiral imbalance on the chiral phase transition in the Tpc − ω plane is investigated. Research manifests that, as μ5 increases, the critical point of the Tpc − ω plane chiral phase transition will move closer to the T axis. This means that the chiral chemical potential...
The Energy-Energy Correlators (EEC), initially developed in $e^+e^-$ collisions, provide a powerful method for probing the angular structure of energy flows within jets. In hadronic collisions with transverse polarization, the polarized EEC (pEEC) offers unique sensitivities to parton spin-orbit correlations and spin-dependent transverse-momentum-dependent (TMD) effects. In this presentation,...
Ultra-relativistic nuclear collisions create the quark–gluon plasma (QGP) known as the hottest, least viscous, and most vortical fluid ever produced in terrestrial laboratories. Its vortical structure has been uncovered through the spin polarization of Lambda ($\Lambda$) hyperons, attributed to the spin–orbit coupling that transfers the system’s orbital angular momentum to the quark spin,...
Short-Range Correlations (SRC) emerge when a proton and neutron within a nucleus come into close proximity - at distances comparable to the nucleon radius - forming a high-momentum, strongly interacting pair. This phenomenon offers a unique window into the transition region between two descriptions of nuclear matter: the low-resolution picture of nuclei as systems of protons and neutrons, and...
In the recent years, it has been realized that deep-inelastic scattering with polarization control could provide a variety of spin and azimuthal angle dependent observables sensitive to the quark-gluon interactions. New parton distributions and fragmentation functions have been introduced to describe the rich complexity of the hadron structure and move towards a multi-dimensional imaging of...
We report our lattice QCD calculation of the nucleon electric dipole moment (EDM) induced by the theta term. We use lattice chiral fermions in our calculation, which provides a fermionic definition of the topological charge exhibiting small discrete effects. Also, the use of chiral fermions guarantees a correct chiral limit even at finite lattice spacings and enables us to reliably extrapolate...
SpinQuest at Fermilab is a fixed-target experiment to primarily measure the Drell-Yan process using transversely polarized NH$_3$ and ND$_3$ targets and unpolarized 120-GeV proton beam. In the Drell-Yan process, a quark in one scattering hadron and an anti-quark in the other hadron annihilate into a virtual photon and then decay into a muon (lepton) pair. The angular distribution of...
I will report our recent results on proton spin structure from a light-front Hamiltonian approach. In this approach we obtain the light-front wave function of the proton through solving the eigenvalue problem of the light-front Hamiltonian of QCD in a basis based on the Fock-sector expansion. Then using the obtained light-front wave function we calculate the observables characterizing the spin...
Recent experimental success of detecting the spin polarization of Lambda hyperons in heavy-ion collisions enables us to extract the novel properties of fluid vorticity and spin transport of quark gluon plasma (QGP). These findings motivated the development of a hydrodynamics-like theory for spin polarization and transport. We will discuss the construction of such a theory (the relativistic...
The Electron-Ion Collider (EIC), scheduled to commission in the early 2030s, will be the world’s first facility that collides a polarized electron beam with a polarized proton beam as well as ion beams. The collider will be built at the Brookhaven National Lab (BNL). The Electron-Proton/Ion Collider (ePIC) is a general purpose detector to be built at the six-o’clock interaction point (IP6) of...
Our study, rooted in hadron physics, addresses the incomplete information limitation of traditional parton distribution functions. We investigate the six-dimensional (6D) light-front Wigner distribution function of the proton (a spin-1/2 hadron) using the 6D light-front Wigner distribution framework constructed by our team.
At the leading twist, 16 independent distribution functions...
Using the anisotropic relativistic fermion action on isotropic lattice, we present a systematic study of the masses and lepton decay constants of the mesons with the bottom quark based on the 2+1 flavor tadpole improved clover ensembles at six different lattice spacings from 0.05 to 0.11 fm, various pion masses from 130 to 360 MeV, and several values of the strange quark mass. We also propose...
Jet transverse single spin asymmetries, $A_N$, are only sensitive to the
initial state effects as final state effects are not present. They are
therefore an excellent tool to single out the quark-gluon and tri-gluon
correlation functions that are the higher-twist equivalents to the
transverse momentum moments of the Sivers functions for quarks and
gluons. sPHENIX has taken transversely...
The “local Lambda polarization puzzle” in relativistic heavy-ion collisions has challenged conventional models based solely on thermal vorticity, which fail to reproduce the observed sign of local polarization. Recently, incorporating shear-induced polarization (SIP) successfully reproduces the sign and opens the path toward a quantitative description of spin polarization.
Using 3+1D MUSIC...
We investigate semi-inclusive deep inelastic scattering (SIDIS) off a tensor-polarized spin-1 target, focusing on the production of an unpolarized hadron. We derive a comprehensive differential cross-section expression, characterized by 23 structure functions, which depend on the target spin states and the azimuthal distribution of the final-state hadron.
Within the TMD factorization...
The spin structure function $g_1$ is important for understanding the quark spin contribution to the overall spin of nucleons, which has been a long standing puzzle in nuclear physics. Through the $Q^{2}$ dependence of $g_1$, the structure function is also sensitive to the gluon spin contribution. In addition, it is important for testing the Bjorken sum rule and can provide a unique way of...
We investigate the Sivers asymmetry in the production of vector mesons, specifically $\rho^0$ and $K^*$, in SIDIS processes in the TMD factorization framework. By employing the Sivers function extracted from pion and kaon production data, we calculate the transverse single-spin asymmetry for $\rho^0$ production and compare it with recent COMPASS measurements. Our results align well with the...
In this talk, we propose nucleon energy correlators (NECs) as a novel framework to probe electroweak light-quark dipole operators in unpolarized deep-inelastic scattering. These operators encode chirality-flipping interactions and typically appear quadratically in unpolarized processes. We construct a chiral-odd quark NEC that accesses quark transverse spin via azimuthal asymmetries in the...
Theoretical developments in relativistic spin hydrodynamics, which explicitly describes the internal angular momentum of a fluid element as spin, have progressed rapidly since the experimental observation of the global spin polarization of Λ hyperons in relativistic heavy-ion collisions. However, numerical simulations of relativistic spin hydrodynamics remain underdeveloped due to significant...
Transverse single spin asymmetries (TSSAs, denoted AN ) in transversely
polarized p↑ + p collisions provide critical insights into the proton’s spin structure, yet their unexpectedly large magnitudes at forward rapidities remain a
puzzle. Observed across experiments, including those at RHIC, these asymmetries have yet to be fully explained by theoretical models, such as those based...
The upcoming MOLLER (Measurement Of Lepton Lepton Electroweak Reaction) experiment at Jefferson Lab aims to measure parity violation in fixed-target electron-electron scattering with unprecedented precision and significantly extend the reach for new dynamics beyond the Standard Model in the electroweak sector. Using the high-intensity, high-precision 11 GeV electron beam at Jefferson Lab,...
Direct photon single spin asymmetries, $A_N$, have the advantage that they
are not sensitive to final state effects and that the hard scattering
process is predominantly quark-gluon scattering at RHIC energies.
Therefore, direct photons provide a clean probe to study the quark-gluon
and tri-gluon correlations in single spin asymmetries with particularly
the latter hardly constrained at...
The transverse single-spin asymmetry ($A_{\mathrm{N}}$) serves as a crucial probe for understanding the mechanisms of particle production in polarized high energy particle collisions as well as the internal dynamics of quarks and gluons within a polarized nucleon. The RHICf collaboration measured a non-zero transverse single-spin asymmetry ($A_{\mathrm{N}}$) for very forward ($\eta > 6$)...
We derive a formulation of relativistic spin hydrodynamics with totally antisymmetric spin tensors that satisfy the Frenkel-Mathisson-Pirani condition. In our proposed spin hydrodynamics, the second law of thermodynamics is fulfilled by the spin-induced corrections in the heat flow, the viscous tensor, and the antisymmetric part of the energy-momentum tensor. These corrections are interpreted...
The study of the charmed baryons is crucial for investigating the strong and weak interactions in the Standard Model and for gaining insights into the internal structure of baryons. In an $e^{+} e^{-}$ experiment the lightest charmed baryon, $\Lambda_c^{+}$, can be produced in pairs through the single photon annihilation process. This process can be described by two complex electromagnetic...
Understanding the three-dimensional spin structure of the nucleon is one of the key questions in QCD. Among the transverse-momentum-dependent (TMD) PDFs, the TMD helicity distributions in particular are poorly constrained. Measurements of the longitudinal single-spin asymmetry ($A_L$) of $W^\pm$ bosons in polarized proton-proton collisions at RHIC provides a unique opportunity for accessing...
New interactions mediated by novel particles propose solutions to several important questions in modern physics.
Axions serve as examples of such particles; they are lightweight and interact weakly with ordinary matter.
This category of particles, including those similar to axions—termed Axion-Like Particles (ALPs)—emerges from diverse theoretical frameworks, including the Peccei-Quinn...
Neutral mesons transverse single spin asymmetries, $A_N$, provide insights
into the spin-orbit correlations inside the nucleon via higher twist
correlation functions. As forward rapidities they are known to be very
large while at central rapidities vanishing asymmetries have been
measured. The sPHENIX experiment with electromagnetic calorimetry over a
rapidity range from -1.1 to 1.1 will...
In this talk, I present our recent investigation of charmonium systems in strong external magnetic fields using a relativistic light-front Hamiltonian approach within the basis light-front quantization (BLFQ) framework. By solving the eigenvalue problem for the invariant mass squared operator — incorporating confinement potentials and one-gluon-exchange interactions — we compute the mass...
We investigate $\Lambda$ production in semi-inclusive deep inelastic scattering using a polarized lepton beam and find that the spin transfer is significantly suppressed by target fragmentation. As further demonstrated by a model estimation, experimental data can be well described once the target fragmentation is taken into account. Our findings suggest that, at the medium-energy scales of...
The proposed Electron-Ion Collider in China (EicC) envisions advancing China's future High-Intensity heavy-ion Accelerator Facility (HIAF) through strategic upgrades to establish a polarized electron-ion collider. This premier facility will provide a comprehensive experimental platform for nuclear physics, particle physics, and related scientific disciplines in China. Functioning as a modern...
This talk will present the current status of experiments using polarized electrons at the accelerator facilities MAMI and MESA in Mainz. A particular focus will be on the P2 experiment, which aims to precisely determine the weak mixing angle at low momentum transfer. This measurement provides a stringent test of the Standard Model and offers sensitivity to potential new physics at energy...
Time reversal symmetry has long been a subject of interest from pre-modern physics time, since it implies the reversibility of motion. In the K^+→π^0 μ^+ ν (K_μ3) decay, the transverse muon polarization (P_T) is defined as the polarization component perpendicular to the decay plane. A non-vanishing value of P_T provide clear evidence for T-violation under the condition that spurious effects...
Jets produced in association with a ${Z^0}$ or ${W^\pm}$ boson in hadronic collisions are naturally polarized due to the parity violation of weak interaction, making these processes ideal for extracting information about the longitudinal spin transfer $G_{1L}$, and for studying the phenomenon of polarized jet quenching. In this work, we compute the polarization of $\Lambda$ hyperons in $pp$...
The study of the Collins asymmetry in $p^{\uparrow}p$ collisions provides a crucial experimental probe for quark transversities and polarized transverse-momentum-dependent (TMD) fragmentation functions.
In this talk, we present high-precision measurements of the Collins asymmetry for $\pi^{\pm}$ within jets from transversely polarized ${p^{\uparrow}p}$ collisions at $\sqrt{s}$ = 510 GeV by...
Hyperons were found to be polarized in p-Be collisions at Fermilab as early as 1976, 12 years before the EMC results sparked the "proton spin crisis." Since then, polarized Lambda hyperons have been observed in electron-positron, proton-proton, and proton-ion collisions. However, unlike the extensive study of nucleon spin structure, the origin of Lambda polarization lacks systematic...
We implement a variational quantum algorithm to investigate the chiral condensate in a 1+1 dimensional SU(2) non-Abelian gauge theory. The algorithm is evaluated using a proposed Monte Carlo sampling method, which allows the extension to large qubit systems. The obtained results through quantum simulations on classical and actual quantum hardware are in good agreement with exact...
Parity played a very important role in the development of the Standard Model (SM), as well as subsequent precision tests of the latter through a determination of the weak mixing angle. The longitudinal beam polarization of the proposed Electron-ion collider in China (EicC) offers a new possibility in this regard, and in a regime unexplored before. In this talk and based on our recent...
According to current understanding, the QCD vacuum contains a condensate of quark-antiquark pairs: $u\bar{u}$, $d\bar{d}$, and $s\bar{s}$. Due to the vacuum’s quantum numbers, $J^{PC} = 0^{++}$, these pairs are expected to appear as maximally entangled spin-triplet states with aligned spins. A recent proposal suggests that the $s\bar{s}$ pairs in the quark condensate may be experimentally...
We present a detailed spin-parity analysis of near-threshold structures in the fully-charm tetraquark sector, using a matrix-element-based approach applied to the J/\psi J/\psi \rightarrow 4\mu final state. Based on the full Run-2 dataset from the CMS experiment, multiple J^P hypotheses are tested using kinematic distributions of the four-muon system. A set of spin-parity combinations, J^P =...
We present a novel framework for parameterizing Lorentz spacetime coordinates using coupled rapidity parameters, extending classical special relativity with new insights into rapidity symmetries and spin effects. Building upon the Euler–Hamilton formalism, we introduce angular and transverse rapidities, enabling spectral decompositions of relativistic dynamics into elementary functions even...
We present a lattice QCD calculation of the Collins-Soper kernel, which governs the rapidity evolution of transverse-momentum-dependent (TMD) distributions, using Large Momentum Effective Theory (LaMET). Quasi-TMD wave functions are computed with three meson momenta on CLQCD configurations (multiple lattice spacings) employing clover quarks and varied hadronic states. HYP smearing is applied...
The proposed STCF is a symmetric electron-positron beam collider designed to provide e+e− interactions at a centerof-mass energy from 2.0 to 7.0 GeV. The peaking luminosity is expected to be 0.5×10^35 cm−2s−1. STCF is expected to deliver more than 1 ab−1 of integrated luminosity per year. The huge samples could be used to make precision measurements of the properties of XYZ particles; search...
In high-energy physics, traditional spin-orbit (L-S) decomposition effectively describes 3-point interaction structures and fully characterizes 3-point kinematics. However, its formulation is entirely dependent on the Center-of-Mass Frame (CMF) angular variables $(\theta,\varphi)$, necessitating Lorentz boosts back to the CMF for decomposition in practical calculations, which adds complexity....
The hadronic tensor encodes key information about the internal structure of hadrons, reflecting the non-perturbative features of quantum chromodynamics (QCD). We perform a direct computation of the hadronic tensor in (1+1)-dimensional $U(1)$ and $SU(2)$ gauge theories by evaluating the real-time current-current correlation function using proposed quantum algorithms implemented on classical...
The fragmentation process has been proposed as a possible origin of the transverse $\Lambda$ polarization, described by polarizing fragmentation functions (pFFs). In $pp$ collisions, this mechanism can be studied by measuring the $\Lambda$ polarization within jets. We present the first measurement of the transverse polarization of $\Lambda$/$\overline{\Lambda}$ hyperons relative to the jet...
Atmospheric neutrinos (ATNs) offer a paradigm to understand neutrino properties while it is critical to quantify uncertainties in the flux modelings. Measurement of cosmic ray muons will contribute to the precision measurement of atmospheric neutrino oscillations due to the same parent particles. This letter suggests measuring the polarization of cosmic ray muons with an array strategy good...
We study the pion's leading and sub-leading twist PDFs, i.e., f(x) and e(x), using a newly developed technique within Dyson-Schwinger equations approach. We will show how the complexities brought by high Fock-state components, zero mode issue and dynamical chiral symmetry breaking can be handled in a consistent and symmetry-preserving framework that connects continuum QCD dynamics to...
The STAR Collaboration results on global spin alignment of vector mesons in heavy-ion collisions [1] reveal that quarks in the quark-gluon plasma (QGP) exhibit not only global polarization[2, 3] but also spin correlations, leading the study on spin effects in heavy-ion collisions to a new climax.
A systematic formalism for describing spin correlations in a system of spin-1/2 particles and...
The transverse polarization of $\Lambda$ hyperons in unpolarized hadron--hadron reactions, first observed decades ago, is still not fully understood. The polarizing fragmentation functions, which are expected to contribute to the $\Lambda$ polarization, can be investigated by measuring the $\Lambda/\bar{\Lambda}$ transverse polarization inside jets in $pp$ collisions. In this contribution, we...
The High Intensity heavy-ion Accelerator Facility (HIAF) will be a major workhorse for the accelerator-based (sub)atomic physics in the multi-GeV region in the next decades. As fundamental as the mass, spin plays a profound role in the structure of microscopic particles and interactions among them. Besides, spin has long provided unique approaches to test fundamental symmetries and to search...
A polarized gaseous target, operated in combination with the high-energy and high-intensity LHC beams, has the potential to open new physics frontiers and to deepen our understanding of the strong interaction in the non-perturbative regime of QCD. Specifically, the LHCspin project aims to perform spin-physics studies in high-energy polarized fixed-target collisions using the LHCb detector....
The muon magnetic anomaly, $a_\mu = (g-2)/2$, can be both measured and computed to a very high precision, making it a powerful probe to test the Standard Model of particle physics and search for new physics. The Fermilab Muon g-2 Collaboration has recently released the third and final measurement of the magnetic anomaly of the positive muon. The measurement shows excellent agreement with the...
The research addresses two fundamental questions in particle physics and cosmology: the fate of antimatter after the Big Bang and the nature of Dark Matter (DM). Its focus lies on the study of Electric Dipole Moments (EDMs) in particles such as protons and deuterons, explored through polarized particle beams stored in a dedicated ring.
Up to now, experimental efforts have been carried out...
We present an analytically solvable model based on the blast-wave picture of heavy-ion collisions with flow-momentum correspondence. It can describe the key features of spin polarizations in heavy-ion collisions. With the analytical solution, we can clearly show that the spin polarization with respect to the reaction plane is governed by the directed flow, while the spin polarization along the...
The SpinQuest experiment leverages a transversely polarized solid-state target to investigate the orbital angular momentum of the nucleon by probing sea quarks through the Drell-Yan process, enabling a measurement of the Sivers asymmetry. The Drell–Yan process is initiated by Fermilab’s 120 GeV Main Injector proton beam, delivering intensities of up to 3E12 protons per 4-second spill. The...
The structures related to shear and shear viscosity may appear in the expansion of energy-momentum tensor (EMT) in various processes.Such terms in various channels may be related either to naive T-oddness (like for Single Spin Asymmetries) or exotic quantum numbers. Their presence is constrained by the equivalebnce principle (EP) which holds exactly (in the forward limit) in the case of...
The shear-induced polarization plays a crucial role in understanding the local polarization of $\Lambda$ and $\overline{\Lambda}$ hyperons. A key puzzle is whether the shear-induced polarization is non-dissipative or not. In this work, we analyzed the shear-induced polarization and the anomalous Hall effects using the entropy flow and H-theorem introduced from quantum (chiral) kinetic theory....
To produce high-intensity polarized beams of deuterons and protons, the Laboratory of High Energy Physics (LHEP) at JINR is developing a Source of Polarized Ion (SPI).
Within the framework of the SPI project, low-energy polarimeters are being developed to measure degree of polarization during beam transport at energies up to 5 MeV/n. These include:
• An NRP (Nuclear Reaction Polarimeter) is...
The JINR accelerator complex utilizes the SPI source [1] for generating polarized deuteron and proton beams, based on atomic beam technology with accumulation in a charge-exchange plasma ionizer. The traditional collinear scheme has limitations, including increased beam divergence and higher emittance, which reduce generation efficiency.
To address these issues, an design with a T-shaped...
In 2024, the sPHENIX experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory completed its first ever transversely polarized proton data taking, collecting approximately 100 billion unbiased collisions. The sPHENIX tracking system, composed of a vertex detector with monolithic active pixel sensor technology, an intermediate silicon strip detector, and a compact time...
To investigate the internal spin structure of nucleons and explore fundamental phenomena such as parity and time-reversal symmetry violations, polarized deuteron beams play a pivotal role as they serve as a unique substitute for polarized neutron beams and enable access to tensor polarization—a critical feature of spin-1 systems that provides distinct insights beyond vector polarization. This...
