arXiv subjects

Zhimin Zhu

Publications and source records attributed to Zhimin Zhu.

12 recordsLinked to original sources

arXiv2026

Unified description of Sivers and Boer-Mulders asymmetries from twist-3 correlations

We present the first calculation of the Efremov-Teryaev-Qiu-Sterman functions and associated twist-3 quark-gluon correlation functions for both the proton and pion. These functions are determined using the light-front wave functions obtained by diagonalizing a light-front effective Hamiltonian within a Fock space truncated to include a dynamical gluon. We compute the twist-3 correlations in the hard-pole region and extrapolate them to the soft-gluon pole limit. After the scale evolutions, our predictions demonstrate quantitative consistency with recent experimental extractions, providing a unified description of the Sivers and Boer-Mulders asymmetries from a light-front Hamiltonian approach.

hep-ph↗

arXiv2026

Transverse Structure of the Kaon: A light-front Hamiltonian Approach

We employ the Basis Light-Front Quantization (BLFQ) framework to compute the leading-twist (twist-2) and subleading-twist (twist-3) transverse-momentum-dependent parton distribution functions (TMDs) of the kaon. The light-front wave functions are obtained by diagonalizing a light-front QCD Hamiltonian that includes quark-antiquark (|q\bar{q}\rangle) and quark-antiquark-gluon (|q\bar{q}g\rangle) Fock components together with a three-dimensional confinement. Using the QCD equations of motion, the twist-3 TMDs are decomposed into twist-2 constributions and genuine twist-3 terms, the latter encoding quark-quark-gluon correlations beyond the probabilistic picture. These genuine twist-3 constributions arise from the interference between the |q\bar{q}\rangle and |q\bar{q}g\rangle sectors, which are usually negelected in the Wandzura-Wilczek approximation. This work provides the first theoretical predictions of kaon subleading-twist TMDs that explicitly account for Fock-sector interference. In addition, we present results for the kaon's twist-2 and twist-3 collinear parton distribution functions (PDFs). The twist-2 PDFs are found to be in good agreement with the recent global analysis by the JAM collaboration.

hep-ph↗

arXiv2026

Helium-3 relativistic wave function in light-front dynamics

The relativistic wave function of $^3$He nucleus is calculated in the framework of Light-Front Dynamics. It is determined by 32 spin-isospin components, each of which depends on five scalar variables. For NN interaction, the one-boson exchange model is assumed, but without a potential approximation. The relativistic effects manifest themselves in deviation of the relativistic components from the non-relativistic input, in the appearance of the components absent in the non-relativistic limit, and in dependence of solutions on specific variables that don't exist in the non-relativistic wave function.

nucl-th↗

arXiv2025

Basis light-front quantization approach to $Λ$ and $Λ_c$ and their isospin triplet baryons

We obtain the masses, the electromagnetic properties, and the parton distribution functions (PDFs) of $Λ$, $Λ_c$, and their isospin triplet baryons, i.e, $Σ^0$, $Σ^+$, $Σ^-$ and $Σ_c^0$, $Σ_c^+$, $Σ_c^{++}$ from a light-front effective Hamiltonian in the leading Fock sector in the basis light-front quantization framework. The light-front wave functions of these baryons are given by the eigenstates of the effective Hamiltonian consisting of a three-dimensional confinement potential and a one-gluon exchange interaction with fixed coupling. The masses of these baryons in our approach are in the experimental range while isospin-dependent mass differences are too small. Meanwhile, the electromagnetic properties are in agreement with the available experimental data, the lattice QCD simulations, and the other theoretical calculations. We also present the gluon and the sea quark PDFs, which we generate dynamically from the QCD evolution of the valence quark distributions.

hep-ph↗

arXiv2025

Dynamical gluon effects in the three-dimensional structure of pion

We investigate the internal structure of the pion, including the contributions from one dynamical gluon, using the basis light-front quantization (BLFQ) approach. By solving a light-front QCD Hamiltonian with a three-dimensional confining potential, we obtain the light-front wavefunctions (LFWFs) for both the quark-antiquark and quark-antiquark-gluon Fock sectors. These wavefunctions are then employed to compute the unpolarized generalized parton distributions (GPDs) and the transverse-momentum-dependent parton distributions (TMDs) of valence quarks and gluons. We also extract the transverse spatial distributions, providing the squared radii of quark and gluon densities in the impact-parameter space. This work contributes toward a three-dimensional understanding of the pion's internal structure in both momentum and coordinate space.

hep-ph↗

arXiv2025

Relativistic $^3$He light-front wave function

The relativistic light-front (LF) wave function of $^3$He is determined by the three-body LF equation for the Faddeev components in the momentum space. As an interaction, we take the one-meson exchange kernels, without the potential approximation. Within the explicitly covariant formulation of LF dynamics, we calculate the full relativistic $^3$He LF wave function, comprising 32 spin-isospin components. In the non-relativistic domain, five of these components dominate and closely resemble their non-relativistic counterparts. Relativistic effects manifest themselves in deviations in relativistic domain of these components from the non-relativistic ones and in appearance of new components.

nucl-th↗

arXiv2025

Transverse structure of the proton beyond leading twist: A light-front Hamiltonian approach

Within the Basis Light-Front Quantization framework, we systematically investigate the subleading twist (twist-3) transverse-momentum-dependent parton distribution functions (TMDs) of the proton beyond the Wandzura-Wilczek (WW) approximation. The subleading twist TMDs are not independent and can be decomposed into twist-2 and genuine twist-3 terms from the equations of motion. The latter involves quark-quark-gluon correlations and contains interferences between two light-front Fock sectors, $|qqq\rangle$ and $|qqqg\rangle$, which are usually neglected in the WW approximation.

hep-ph↗

arXiv2025

Strange mesons with one dynamical gluon: A light-front approach

We obtain the mass spectra of strange mesons using a light-front quantized Hamiltonian with Quantum Chromodynamics (QCD) input, incorporating quark-antiquark and quark-antiquark-gluon Fock components, along with a three-dimensional confinement. We work within the basis light-front quantization framework. The resulting eigenvectors can simultaneously describe the kaon's electromagnetic form factor, decay constant, distribution amplitude, and quark and gluon distribution functions under QCD scale evolution. Using the obtained kaon parton distribution functions (PDFs), supplemented by established nuclear PDFs, we also predict the kaon-nucleus-induced Drell-Yan cross section, which is expected to be measured soon by COMPASS++/AMBER at CERN.

hep-ph↗

arXiv2024

Pion to photon transition form factor: Beyond valence quarks

We investigate the singly virtual transition form factor (TFF) for the $π^0\toγ^*γ$ process in the space-like region using the hard-scattering formalism within the Basis Light-Front Quantization (BLFQ) framework. This form factor is expressed in terms of the perturbatively calculable hard-scattering amplitudes (HSAs) and the light-front wave functions (LFWFs) of the pion. We obtain the pion LFWFs by diagonalizing the light-front QCD Hamiltonian, which is determined for its constituent quark-antiquark and quark-antiquark-gluon Fock sectors with a three-dimensional confinement. We employ the HSAs up to next-to-leading order (NLO) in the quark-antiquark Fock sector and leading order (LO) in the quark-antiquark-gluon Fock sector. The NLO correction to the TFF in the quark-antiquark Fock sector is of the same order as the LO contribution to the TFF in the quark-antiquark-gluon Fock sector. We find that while the quark-antiquark-gluon Fock sector has minimal effect in the large momentum transfer ($Q^2$) region, it has a noteworthy impact in the low-$Q^2$ region. Our results show that, after accounting for both Fock sectors, the TFF within the BLFQ framework aligns well with existing experimental data, particularly in the low $Q^2$ region.

hep-ph↗

arXiv2023

Transverse momentum structure of strange and charmed baryons: a light-front Hamiltonian approach

Under the basis light-front quantization framework, we investigate the leading-twist transverse-momentum-dependent parton distribution functions (TMDs) for $Λ$ and $Λ_c$ baryons, the spin-1/2 composite systems consisting of two light quarks ($u$ and $d$) and a $s/c$ quark. We evaluate the TMDs using the overlaps of the light-front wave functions in the leading Fock sector, which are obtained by solving the light-front eigenvalue equation. We also study the spin densities of quarks in momentum space for various polarizations. In the same model, we compare the TMDs of the strange and charmed baryons and the proton by reviewing their spin structures in the quark model and the probabilistic interpretations of their TMDs.

hep-ph↗

arXiv2023

Transverse structure of the pion beyond leading twist with basis light-front quantization

We investigate the twist-$3$ transverse-momentum-dependent parton distribution functions (TMDs) of the pion with basis light-front quantization. The twist-3 TMDs are not independent and can be decomposed into twist-$2$ and genuine twist-$3$ terms from the equations of motion (EOM). We compute the TMDs from the resulting light-front wave functions obtained by diagonalizing the light-front QCD Hamiltonian, determined for pion's constituent quark-antiquark and quark-antiquark-gluon Fock sectors, with three-dimensional confinement. We also obtain the twist-3 parton distribution functions (PDFs) and show that they preserve the sum rule, which affirms the robustness of our approach. This is the first time that theoretical predictions are made for subleading twist structures of the pion containing interference terms between two light-front Fock sectors.

hep-ph↗

arXiv2023

MC-MLP:Multiple Coordinate Frames in all-MLP Architecture for Vision

In deep learning, Multi-Layer Perceptrons (MLPs) have once again garnered attention from researchers. This paper introduces MC-MLP, a general MLP-like backbone for computer vision that is composed of a series of fully-connected (FC) layers. In MC-MLP, we propose that the same semantic information has varying levels of difficulty in learning, depending on the coordinate frame of features. To address this, we perform an orthogonal transform on the feature information, equivalent to changing the coordinate frame of features. Through this design, MC-MLP is equipped with multi-coordinate frame receptive fields and the ability to learn information across different coordinate frames. Experiments demonstrate that MC-MLP outperforms most MLPs in image classification tasks, achieving better performance at the same parameter level. The code will be available at: https://github.com/ZZM11/MC-MLP.

cs.CV↗