Li Guang-Lie

High-Energy Proton-Induced Dimuon Production from Nuclei

In the framework of the Glauber model, taking into account the energy loss of the beam proton through the nucleus, we analyse the measured Drell-Yan production cross sections for an 800 GeV proton beam incident on Be, Fe and W nuclear targets. We have found that the nuclear Drell-Yan cross section ratios are suppressed due to the energy loss in the initial state. The calculated results of the energy loss are in very good agreement with the Fermilab experiment 866.

Nuclear Effects in Structure Functions xF3(x,Q2) from Charge Current Neutrino Deep Inelastic Scattering

By taking advantage of the model-independent nuclear parton distributions, the structure functions xF3(x,Q2) are calculated, in comparison with the experimental data from CCFR neutrino–nuclei charge current deep inelastic scattering. It is shown that shadowing and anti-shadowing effects occur in valence quark distributions for small and medium x regions, respectively. It is suggested that the neutrino experimental data should be employed in the future for pinning down the nuclear parton distributions.

Nuclear Effects in Polarized Proton?Deuteron Drell?Yan Processes

The longitudinally polarized Drell-Yan process is one of the most powerful tools to probe the structure of hadrons. By means of the recent formalism of the polarized proton-deuteron (pd) Drell-Yan, we calculate the ratio of the proton-deuteron Drell-Yan cross section to the proton-proton (PP) one Deltasigma(pd)/2Deltasigma(pp) in the polarized case. The theoretical results can be compared with future experimental data to confirm the nuclear effect due to the 6-quark cluster in deuteron.The longitudinally polarized Drell–Yan process is one of the most powerful tools to probe the structure of hadrons. By means of the recent formalism of the polarized proton–deuteron (pd) Drell–Yan, we calculate the ratio of the proton–deuteron Drell–Yan cross section to the proton–proton (pp) one Δσpd/2Δσpp in the polarized case. The theoretical results can be compared with future experimental data to confirm the nuclear effect due to the six-quark cluster in deuteron.

Energy Loss of Fast Quarks in Nuclear Drell?Yan Dimuon Production

The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effects on the parton distribution as in the deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell?Yan process. By means of the quark energy loss parametrization given in literature and the nuclear parton distribution extracted only with lepton?nucleus deep inelastic scattering experimental data, measured Drell?Yan production cross sections are analysed for 800-GeV protons incident on a variety of nuclear targets from FNAL E866. The average energy loss of quarks are given by fitting the Fe/Be and W/Be Drell?Yan cross section ratios versus the incident parton momentum fraction.

ηc Diffractive Production in the Direct Photon Process

Based on the factorization theorem for lepton induced hard diffractive scattering and color octet heavyquarkonium production mechanism, ηc diffractive production in the direct photon process is studied. The results showthat this process can be measured at DESY HERA, and ηc production has different features from J/ψ production,which is weakly affected by the initial and final state gluon radiation. Therefore, ηc photoproduction can be viewed asreliable estimate. The experimental study of this process can give valuable insight in the color octet heavy quarkoniumproduction mechanism.

p-A Drell-Yan Process in the Target Rest Frame

At high energies, Drell-Yan process can be viewed in the target rest frame as bremsstrahlung of massive photons, rather than parton annihilation. In this paper, the ratio of the p-A Drell-Yan cross section per nucleon for an 800 GeV proton beam incident on Fe, W, and Be targets are calculated by means of the color dipole approach in the target rest system. It is shown that our calculations can quite well fit the Fermilab E866 experimental data with considering the nuclear shadowing effect in p-A Drell-Yan process and without the energy loss effect in it.

Abundance distribution of slow-process main heavy elements in AGB stars

By re-analysing the results of the theoretical abundance of asymptotic giant branch (AGB) stellar models and the observed abundances of 51 AGB samples, we find that the abundance distribution of s-process main heavy (SMH) elements of any AGB star is similar to the scaled s-process main component of the solar system. This means that superposition of the SMH element abundance distributions of AGB stars should be similar to the scaled solar s-process main component. As a conclusion, the abundance pattern of the solar SMH elements is not only an average result of a complex chemical evolution of galaxy, but also a typical one that can be used as a standard in abundance investigation.

A New Effect in the QCD Fusion of Nuclear Partons

The parton fusion in nucleus at the leading order of recombination is investigated based on perturbative QCD. We compute various cut diagrams including the nuclear parton fusion, and find that the parton-fusion effects depend on the nuclear QCD structure.

A twist-4 effect in the parton evolution processes

Recently, a research group reported that they can fit the F2 data well by using the Altarelli-Parisi evolution equation with a valence-like initial gluon distribution, which means that we need not consider the high twist effects in the proton. In this letter, we point out that their valence-like initial gluon distribution is unreasonable for the proton structure function. With the reasonable initial distributions, we find that the high twist corrections to the Altarelli-Parisi evolution equation is necessary.

A Study of the Off-Shell Calculation in the Quark-Gluon Vertex

The off-shell calculation is studied in the quark-gluon vertex with dimension-4 gluon condensate in the fixed-point gauge. It is noted that the evaluated result depends on whether the zero point is set on the fermionic or gluonic line for the off-shell calculation in the quark-gluon vertex. In order to obtain more reasonable results, it is suggested that a covariant gauge should be adopted.