相关论文: Contribution to the Proton Spin Puzzle from Helici…
We apply the valence quark model recently calculated for polarized proton to constrain the non-perturbative initial condition for the small-$x$ helicity evolution. The remaining free parameters are constrained by performing a global…
Helicity of quarks and gluons inside the proton at small Bjorken $x$ is one of the missing pieces of the proton spin puzzle, with limited experimental results due to various challenges. To address the problem, we derive under the framework…
A small-$x$ helicity evolution has been derived in 2016-18 and received an important modification in 2022. This article discusses its general framework and summarizes the recent theoretical developments, including the asymptotic behaviors…
The proton spin puzzle is a longstanding problem in high-energy nuclear physics: how the proton spin distributes among the spin and orbital angular momenta of the quarks and gluons inside. Two of the unresolved pieces of the puzzle are the…
The recently revised small-$x$ helicity evolution, resumming the double-logarithmic factor, $\alpha_s\ln^2(1/x)$, allows for the study of helicity distributions of quarks and gluons at small Bjorken $x$, corresponding to high center-of-mass…
The proton spin puzzle denotes the challenge of describing the proton's spin in terms of the angular momenta of the quarks and gluons which comprise it. These quarks and gluons carry a fraction $x$ of the proton's momentum. Contributions…
We perform a phenomenological study of helicity-dependent parton distribution functions (PDFs) using small-$x$ helicity evolution equations, incorporating for the first time single-inclusive jet production data in polarized proton-proton…
We construct small-$x$ evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function. These evolution equations resum powers of $\alpha_s \, \ln^2 (1/x)$ in the…
This dissertation highlights the contributions I have made to the field of theoretical nuclear physics, specifically in high-energy Quantum Chromodynamics (QCD). High-energy QCD is a robust subject and my research is refined to the…
We rederive the small-$x$ evolution equations governing quark helicity distribution in a proton using solely an operator-based approach. In our previous works on the subject, the evolution equations were derived using a mix of diagrammatic…
So far the analyses of the polarized structure functions of the proton and neutron have been limited to the evaluation of their integrals and comparing them to the prediction of the static quark model of the nucleon. We extended our…
The total gluon helicity in a polarized proton, measurable in high-energy scattering, is shown to be the large momentum limit of a gauge-invariant but non-local, frame-dependent gluon spin $\vec{E}\times \vec{A}_\perp$ in QCD. This opens a…
We present a Monte Carlo based analysis of the combined world data on polarized lepton-nucleon deep-inelastic scattering at small Bjorken $x$ within the polarized quark dipole formalism. We show for the first time that double-spin…
How quarks and gluons conspire to provide the total spin of proton is a long-standing puzzle in quantum chromodynamics (QCD). The unique capability of RHIC, that can provide longitudinally polarized $p+p$ collisions at both $\sqrt{s} = 200$…
We obtain the gluon parton distribution functions (PDFs) in the proton within the extended light-front holographic QCD framework, where the proton couples with the spin-two Pomeron in Anti-de Sitter space, together with constraints imposed…
We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in…
In the past year, polarized deep inelastic scattering experiments at CERN and SLAC have obtained structure function measurements off proton, neutron and deuteron targets at a level of precision never before achieved. The measurements can be…
Proton is a composite particle, so its spin S_P is made from the spins of the partons which the proton consists of. The discrepancy between S_P = 1/2 and the experimentally detected sum of the parton spins was named Proton Spin Puzzle.…
I review the constituent contributions to the spin of the proton extracted from recent data at CERN, SLAC and DESY. The valence, sea quark and antiquark spin-weighted distributions are determined separately. The data appear to imply a small…
We present a numerical solution of the revised version of the small-$x$ helicity evolution equations at large $N_c$ and $N_f$. (Here $N_c$ and $N_f$ are the numbers of quark colors and flavors, respectively.) The evolution equations are…