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...
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...
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...
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...
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...
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...
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...
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...
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...
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 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...
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 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 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...
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...
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...
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 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 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...
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,...
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...
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...
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...
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 ``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,...
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...
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...
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...
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...
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)...
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...
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 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 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...
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,...
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 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,...
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...
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...
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 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...
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 $pp$...
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...
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 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...
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 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...
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...
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...
The University of New Hampshire (UNH) Nuclear Physics Group (NPG) is planning to run the $b_{1}$ and $A_{zz}$ experiment at JLab in Hall C using an 11.0 GeV, High Luminosity electron beam ($10^{38}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$) with 115 nA beam current, a 5T superconducting magnet, the $ND_{3}$ dynamically polarized target and the HallC stacked spectrometer to study the deuteron spin...
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 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...
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...
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,...
