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Xurong Chen

Publications and source records attributed to Xurong Chen.

155 records · Page 9Linked to original sources
arXiv2015

Nuclear force and the EMC effect

A linear correlation is shown quantitatively between the magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) and the nuclear residual strong interaction energy (RSIE) obtained from nuclear binding energy subtracting the Coulomb energy contribution. This phenomenological relationship is used to extract the size of in-medium correction (IMC) effect on deuteron and to predict the EMC slopes $|dR_{EMC}/dx|$ of various nuclei. We further investigate the correlations between RSIE and other quantities which are related to the EMC effect. The observed correlations among RSIE, EMC slope and SRC ratio $R_{2N}N_{total}/N_{np(^3S_1)}$ imply that the local nuclear environment drives the modification of quark distributions.

nucl-th↗
arXiv2015

Valence quark distributions of the proton from maximum entropy approach

We present an attempt of maximum entropy principle to determine valence quark distributions in the proton at very low resolution scale $Q_0^2$. The initial three valence quark distributions are obtained with limited dynamical information from quark model and QCD theory. Valence quark distributions from this method are compared to the lepton deep inelastic scattering data, and the widely used CT10 and MSTW08 data sets. The obtained valence quark distributions are consistent with experimental observations and the latest global fits of PDFs. Maximum entropy method is expected to be particularly useful in the case where relatively little information from QCD calculation is given.

hep-ph↗
arXiv2014

The Y-stringlike behavior of a static hadron at finite T

We look into the signatures of the effective Y-bosonic strings in the gluonic profile due to a system of three static quarks on the lattice. The gluonic distribution is calculated in pure Yang-Mills lattice gauge theory at finite temperature with Polyakov loops operators. The analysis of the action density unveils a filled-$Δ$ distribution. However, we found that these $Δ$-shaped action density profiles are structured from three Y-shaped Gaussian-like flux-tubes. The length of the revealed Y-flux system increases with the increasing of the color source separation and reaches maximum near the deconfinement point. The lattice data for the mean-square width of the gluonic action density have been compared to the corresponding width calculated based on the string model at finite temperature. We assume Y-string configuration with minimal length. The growth pattern of the action density of the gluonic field fits well to junction fluctuations of the Y-baryonic string model for large quark separation at the considered temperatures.

hep-lat↗
arXiv2014

The $R_{uds}$ value in the vicinity of $ψ(3770)$ state

The anomalous line shape of the $ψ(3770)$ state has resulted in some difficulty in the determination of the $R$ value for the continuum light hadron production in the resonance energy range. We parameterize the asymmetric line shape using a Fano-type formula and extract the $R_{uds}$ value to be $2.156\pm 0.022$ from the data of BESIII Collaboration in the energy region between 3.650 and 3.872 GeV. The small discrepancy between experiment and theory is removed. The cross sections of the $e^+e^- \rightarrow hadrons$ are given by subtracting the part of continuum light hadron production and are compared to the data of the $e^+e^- \rightarrow D\bar{D}$ reaction.

hep-ph↗
arXiv2014

The study of $U$-boson from $π^{0}$-meson decays at HIAF energy

Within the frame of LDM (light dark matter)-model, the LDM exchange particle $U$-boson (with mass 10-100 MeV) can be produced from many meson decay process so it attracts a lot of attention. Considering the merit of searching the $U$-boson from $π^{0}$ decay, the momentum spectra of light spin-1 vector $U$-boson from decay channel $π^{0}\rightarrow γU$ and the energy spectra of positron decay from $U\rightarrow e^{+}e^{-}$ at beam energy of 5-10 GeV are first presented by using a relativistic transport (ART) model. Moreover,the feasibility and rationality of searching the $U$-boson in the experiment at HIAF energy are discussed, which will be an important promotion to understand and ultimately detect the $U$-boson, both in theory and experiment.

hep-ph↗
arXiv2014

Applications of a nonlinear evolution equation I: the parton distributions in the proton

The parton distributions in the proton are evaluated dynamically using a nonlinear QCD evolution equation - the DGLAP equation with twist-4 (the GLR-MQ-ZSR) corrections - starting from a low scale $μ^2$, where the nucleon consists of valence quarks. We find that the negative nonlinear corrections can improve the perturbative stability of the QCD evolution equation at low $Q^2$. Our resulting parton distributions of the proton with four free parameters are compatible with the existing databases. We show that the sea quark distributions exhibit a positive and flattish behavior at small $x$ and low $Q^2$. This approach provides a powerful tool to connect the quark models of the hadron and various non-perturbative effects on them at scale $μ^2$ with the measured structure functions at high scale $Q^2>> μ^2$.

hep-ph↗
arXiv2014

Applications of a nonlinear evolution equation II: the EMC effect

The EMC effect is studied by using the GLR-MQ-ZSR equation with minimum number of free parameters, where the nuclear shadowing effect is a dynamical evolution result of the equation, and nucleon swelling and Fermi motion in the nuclear environment deform the input parton distributions. Parton distributions of both proton and nucleus are predicted in a unified framework. We show that the parton recombination as a higher twist correction plays an essential role in the evolution of parton distributions either of proton or nucleus. We find that the nuclear antishadowing contributes a part of enhancement of the ratio of the structure functions around $x\sim 0.1$, while the other part origins from the deformation of the nuclear valence quark distributions. We point out that the nuclear shadowing and antishadowing effects in the gluon distribution are not stronger than that in the quark distributions.

hep-ph↗
arXiv2013

Sudakov Factor in the Deep Inelastic Scattering of a Current off a Large Nucleus

We consider a gedanken experiment of the scattering of a current off a large nucleus to study the gluon saturation at the small-x limit and compute the Sudakov factor of this process through a one-loop calculation. The differential cross section is expressed in term of the Sudakov resummation, in which the collinear and the rapidity divergences are subtracted. We also discuss how to probe the Weizsaecker-Williams (WW) gluon distribution in the process of photon pair production in the pA collisions.

hep-ph↗
arXiv2011

Pion productions by proton and Helium-3 on Au197 target at beam energies of 2.8, 5, 10 and 16.587 GeV/nucleon

Based on a Relativistic Boltzmann-Uehling- Uhlenbeck transport model, proton and $^{3}$He induced reactions on $^{197}$Au target at beam energies of 2.8, 5, 10 and 16.587 GeV/nucleon are studied. It is found that compared with proton induced reactions, $^{3}$He induced reactions give larger cross sections of pion production, about 5 times those of the proton induced reactions. And more importantly, pion production from $^{3}$He induced reaction is more inclined to low-angle emission. Neutrino production via positively charged pion is also discussed accordingly.

nucl-th↗
arXiv2007

Geometric Structure of Two Self-dual Fields with Constraints

A two dimensional Poincar$\acute{e}$-invariant self-dual field with constraints is studied in geometric way. We obtained its symplectic structure and conservative currents on space of solutions, which are also invariant under transformations of Poincar$\acute{e}$ group.

hep-th↗