3He/4He Dilution Refrigerator is the only device at the moment that allows to obtain an ultra-low temperature (down to 5mK) in a continuous mode (for several months and more). In 1966, one of the world's first 3He/4He dilution refrigerators was created in Dubna under the leadership of B.S. Neganov. Since then, more than 10 3He/4He dilution refrigerators have been created in the Low Temperature...
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...
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...
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...
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...
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...
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...
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 $\pi^+\pi^-$...
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 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...
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...
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...
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 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...
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...
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...
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.
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...
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...
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...
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...
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...
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...
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...
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...
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 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...
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...
He–3/He-4 Dilution Refrigerator is the only device at the moment that allows to obtain an ultra-low temperature (down to 5mK) in a continuous mode (for several months and more). In 1966, one of the world's first He–3/He-4 dilution refrigerators was created in Dubna under the leadership of B.S. Neganov. Since then, more than 10 He–3/He-4 dilution refrigerators for experiments with polarized...
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...
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...
We explore the internal structure of the deuteron within the light-front framework, going beyond the traditional proton–neutron description. By incorporating hidden-color degrees of freedom, we model the deuteron as an effective mixture of singlet–singlet and octet–octet color configurations. Our study includes both unpolarized and polarized observables, including the tensor-polarized...
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 have implemented the 3+1 dimensional CLVisc hydrodynamics model with \trento-3D initial conditions to investigate the spin polarization of $\Lambda$ hyperons along the beam direction in p+Pb collisions at $\sqrt{s_{NN}} = 8.16$ TeV. Following our previous theoretical framework based on quantum kinetic theory, we consider three different scenarios: $\Lambda$ equilibrium, $s$ quark...
The observation of hyperon polarization along beam direction ($P_z$) in nucleus-nucleus collisions has opened a new way to study the complex vortical structures of the QGP. With the high-statistics data collected by the CMS experiment, we present the first $P_z$ results for $\Lambda$ and $\bar{\Lambda}$ particles in pPb collision at $\sqrt{s_{NN}}= 8.16$ TeV over a wide transverse momentum...
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...
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...
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...
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...
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...
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...
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...
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...
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 ($\eta > 6$)...
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...
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)...
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 observation of hyperon global polarization and vector meson spin alignment in heavy-ion collisions has revealed that spin phenomena are important probes of quark matter properties. These findings point toward possible spin correlations between quarks and antiquarks in the quark-gluon plasma. Such correlations are sensitive to production mechanism and evolution dynamics of spin...
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...
It has been assumed that nuclear modification does not exist in the longitudinal-transverse structure function ratio $R_N=F_L^N/(2xF_1^N)$ in lepton deep inelastic scattering. This assumption is widely used in obtaining structure functions of the ``nucleon" from nuclear data such as the deuteron ones. However, nuclear modifications do exist theoretically at least at medium- and large-$x$...
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...
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 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 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 =...
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,...
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...
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...
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...
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...
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...
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...
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...
By treating the proton as a quark + interacting-diquark bound state, whose structure is obtained by solving a Poincare covariant Faddeev equation, we provide a comprehensive, coherent set of predictions for unpolarised and polarised proton parton distribution functions (DFs): valence, glue, and four-flavour separated sea. The results address many things including the origin of the proton spin....
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...
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...
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 $pp$...
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...
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...
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...
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...
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...
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...
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...
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...
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,...
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.
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...
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...
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 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...
Structure functions of the spin-1 deuteron will be investigated experimentally from the late 2020's at various facilities such as Thomas Jefferson National Accelerator Facility, Fermi National Accelerator Laboratory, nuclotron-based ion collider facility (NICA), and electron-ion colliders. We expect that a new high-energy spin-physics field could be created by these projects. In this paper...
In relativistic non-central heavy-ion collisions, both initial angular momentum and a strong magnetic field are generated, leading to the phenomenon of hadron spin polarization. In condensed matter physics, fermions can be spin polarized by the combined effects of spin-magnetic field and spin-orbit interactions. This phenomena has been extensively studied with the Landau-Lifshitz-Gilbert (LLG)...
We employ the VQCD model, a holographic approach that dynamically simulates essential QCD characteristics, including linear mass spectra, confinement, asymptotic freedom, and magnetic charge screening, while incorporating quark flavor effects. Using this model, we first calculate the proton mass spectrum and the wave function, incorporating anomalous dimensions to refine our
results. Next, we...
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...
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 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...
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...
In this talk, I will present the first extraction of TMD helicity distributions, by analyzing double spin asymmetry data from SIDIS.
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...
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...
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 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,...
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...
