arXiv subjects

Li-Hua Song

Publications and source records attributed to Li-Hua Song.

13 recordsLinked to original sources

arXiv2021

The Drell-Yan nuclear modification due to the nuclear effects of nPDFs and initial-state parton energy loss

By globally analyzing nuclear Drell-Yan data including all incident energies, the nuclear effects of nPDFs and initial-state parton energy loss are investigated. Based on Landau-Pomeranchuk-Migdal (LPM) regime, the calculations are carried out by means of the analytic parametrizations of quenching weights derived from the Baier-Dokshitzer-Mueller-Peign$\acute{e}$-Schiff (BDMPS) formalism and using the new EPPS16 nPDFs. It is found that the results are in good agreement with the data and the role of the energy loss effect on the suppression of Drell-Yan ratios is prominent, especially for low-mass Drell-Yan measurements. The nuclear effects of nPDFs becomes more obvious with the nuclear mass number A, the same as the energy loss effect. By global fit, the transport coefficient extracted is $\hat{q}=0.26\pm0.04$ GeV$^{2}$/fm. In addition, to avoid diminishing the QCD NLO correction on the data form of Drell-Yan ratios, the separate calculations about the Compton differential cross section ratios $R_{Fe(W)/C}(x_{F})$ at 120GeV are performed, which provides a feasible way to better distinguish the gluon energy loss in Compton scattering. It is found that the role of the initial-state gluon energy loss on the suppression of Compton scattering rations is not very important and becomes disappear with the increase of $x_{F}$.

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arXiv2020

The study of the incoming parton energy loss effect on the NLO nuclear Drell-Yan ratios

At a next-to-leading order calculation, the initial-state energy loss of the quark is investigated by means of the Drell-Yan experimental data including the new E906 measurements. Furthermore, the incoming gluon energy loss effect embedded in the Compton scattering subprocess of the nuclear Drell-Yan process is also examined. The next-to-leading order computations for Drell-Yan ratios are carried out with the SW quenching weights (provided by Salgado and Wiedemann to evaluate the probability distribution that quark (gluon) loses the energy), as well as the nuclear parton distributions (obtained by only fitting the existing experimental data on nuclear structure functions). It is found that the obtained calculations that consider the incoming quark energy loss agree well with the experimental data particularly for E906 data. In addition, the incoming gluon energy loss embodied in the primary next-to-leading order Compton scattering subprocess is not obvious, which may be due to the form of the Drell-Yan differential cross section ratio as a function of the quark momentum fraction ($R_{A_{1}/A_{2}}(x_{1},x_{2},x_{F})$) minimizes the influence of the QCD next-to-leading order correction.

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arXiv2018

The study of gluon energy loss in cold nuclear matter from $J/\psi$ production

The energy loss effects of the incident quark, gluon and the color octet $c\bar{c}$ on $J/\psi$ suppression in p-A collisions are studied by means of the experimental data at E866, RHIC and LHC energy. By the Salgado-Wiedemann (SW) quenching weights and the recent EPPS16 nuclear parton distribution functions together with nCTEQ15, we extract the transport coefficient for the gluon energy loss from the E866 experimental data in the middle $x_{F}$ region ($0.20<x_{F}<0.65$). It is found that the difference between the values of the transport coefficient for light quark, gluon and heavy quark in the cold nuclear matter is very small. The theoretical results modified by the parton energy loss effects are consistent with the experimental data for E866 and RHIC energy, and the gluon energy loss plays a remarkable role on $J/\psi$ suppression in a broad variable range. Since the corrections of the nuclear parton distribution functions in the $J/\psi$ channel are significant at LHC energy, the nuclear modification due to the parton energy loss is minimal. It is worth noting that we use CEM at leading order to compute the p-p baseline, and the conclusion in this paper is CEM model dependent.

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arXiv2016

The energy loss effect of incoming quark in the Drell-Yan reaction off nuclei

By means of the analytic parameterizations of quenching weights based on BDMPS formalism, the leading-order computations for nuclear Drell-Yan differential cross section rations as a function of the quark momentum fraction are performed with the nuclear geometry effect in Drell-Yan dimuon production. The transport coefficient of the incoming quark energy loss in cold nuclear matter is extracted with a global analysis of the experimental data from NA3 and E866 collaborations. The extracted transport coefficient with the analytic parameterizations of BDMPS quenching weights is $\hat{q}=0.37\pm0.05$ GeV$^{2}$/fm. It is found that our predictions are in good agrement with the experimental measurements, and especially the agreement of calculations with NA3 experimental data has a significant improvement. The comparison of the theoretical results and the corresponding experimental data demonstrates intuitively that the energy loss effect of incoming quark is particularly significant at lower incident proton energies. It is hoped that the obtained results relevant to the NA3 experiment ($E_{beam}=150$ GeV) can provide useful reference for the forthcoming E906 Sea Quest experiment ($E_{beam}=120$ GeV).

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arXiv2016

The energy loss effect of incoming gluon from $J/\psi$ production in p-A collisions

The energy loss effect of incoming gluon from $J/\psi$ production in p-A (or d-A) collisions is investigated by means of the E866, RHIC and LHC experimental data. The gluon mean energy loss per unit path length $dE/dL = 2.18\pm0.14$ GeV/fm is extracted by fitting the E866 experimental data for $J/\psi$ production cross section ratios $R_{W(Fe)/Be}(x_{F})$. The obtained result indicates that the incoming gluons lose more energy than the incident quarks. By comparing the theoretical results with E866, RHIC, and LHC experimental data, it is found that the nuclear suppression due to the incident gluon (quark) energy loss reduces (increases) with the increase of the kinematic variable $x_{F}$ (or $y$). The energy loss effect of incoming gluon plays an important role on the suppression of $J/\psi$ production in a wide energy range from $\sqrt{s}=38.7$ GeV to $\sqrt{s}=5.0$ TeV, and the influence of incident quark energy loss can be ignored for high energy(such as at RHIC and LHC energy).

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arXiv2015

Nuclear geometry effect and transport coefficient in semi-inclusive lepton-production of hadrons off nuclei

Hadron production in semi-inclusive deep-inelastic scattering of leptons from nuclei is an ideal tool to determine and constrain the transport coefficient in cold nuclear matter. The leading-order computations for hadron multiplicity ratios are performed by means of the SW quenching weights and the analytic parameterizations of quenching weights based on BDMPS formalism. The theoretical results are compared to the HERMES positively charged pions production data with the quarks hadronization occurring outside the nucleus. With considering the nuclear geometry effect on hadron production, our predictions are in good agreement with the experimental measurements. The extracted transport parameter from the global fit is shown to be $\hat{q} = 0.74\pm0.03 GeV^2/fm$ for the SW quenching weight without the finite energy corrections. As for the analytic parameterization of BDMPS quenching weight without the quark energy E dependence, the computed transport coefficient is $\hat{q} = 0.20\pm0.02 GeV^2/fm$. It is found that the nuclear geometry effect has a significant impact on the transport coefficient in cold nuclear matter. It is necessary to consider the detailed nuclear geometry in studying the semi-inclusive hadron production in deep inelastic scattering on nuclear targets.

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arXiv2013

Energy loss of charm quarks from $J/\psi$ production in cold nuclear matter

$J/\psi$ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution, energy loss of beam proton and the finial state energy loss of color octet $c\overline{c}$. The leading-order computations for $J/\psi$ production cross-section ratios $R_{W/Be}(x_{F})$ are presented and compared with the selected E866 experimental data with the $c\overline{c}$ remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed $J/\psi$ suppression in the experimental data. It is found that the $J/\psi$ suppression on $R_{W/Be}(x_{F})$ from the initial state nuclear effects is more important than that induced by the energy loss of color octet $c\overline{c}$ in the large $x_F$ region. Whether the $c\overline{c}$ pair energy loss is linear or quadratic with the path length is not determined. The obtained $c\overline{c}$ pair energy loss per unit path length $\alpha=2.78\pm0.81$ GeV/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.

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arXiv2013

Atomic mass dependence of hadron production in semi-inclusive deep inelastic lepton-nucleus scattering

Hadron production in lepton-nucleus deep inelastic scattering is studied in a quark energy loss model. The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES pions production data with the quark hadronization occurring outside the nucleus by means of the hadron formation time. It is found that the obtained energy loss per unit length is $0.440 \pm 0.013$ GeV/fm for an outgoing quark by the global fit. It is confirmed that the atomic mass number dependence of hadron attenuation is theoretically and experimentally in good agreement with the $A^{2/3}$ power law for quark hadronization occurring outside the nucleus.

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arXiv2013

Hadron formation in semi-inclusive deep inelastic lepton-nucleus scattering

Hadron production in lepton-nucleus deep inelastic scattering is studied in a model including quark energy loss and nuclear absorption. The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES experimental data with the quark hadronization occurring inside the nucleus by means of the hadron formation time. It is shown that with increase of the energy fraction carried by the hadron, the nuclear suppression on hadron multiplicity ratio from nuclear absorption gets bigger. It is found that when hadronization occurs inside the nucleus, the nuclear absorption is the dominant mechanism causing a reduction of the hadron yield. The atomic mass dependence of hadron attenuation for quark hadronization starting inside the nucleus is confirmed theoretically and experimentally to be proportional to $ A^{1/3}$.

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arXiv2012

Systematic analysis of the incoming quark energy loss in cold nuclear matter

The investigation into the fast parton energy loss in cold nuclear matter is crucial for a good understanding of the parton propagation in hot-dense medium. By means of four typical sets of nuclear parton distributions and three parametrizations of quark energy loss, the parameter values in quark energy loss expressions are determined from a leading order statistical analysis of the existing experimental data on nuclear Drell-Yan differential cross section ratio as a function of the quark momentum fraction. It is found that with independence on the nuclear modification of parton distributions, the available experimental data from lower incident beam energy rule out the incident-parton momentum fraction quark energy loss. Whether the quark energy loss is linear or quadratic with the path length is not discriminated. The global fit of all selected data gives the quark energy loss per unit path length {\alpha} = 1.21\pm0.09 GeV/fm by using nuclear parton distribution functions determined only by means of the world data on nuclear structure function. Our result does not support the theoretical prediction: the energy loss of an outgoing quark is three times larger than that of an incoming quark approaching the nuclear medium. It is desirable that the present work can provide useful reference for the Fermilab E906/SeaQuest experiment.

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arXiv2011

Nuclear effects on J/{\psi} production in proton-nucleus collisions

The study of nuclear effects for J/{\psi} production in proton-nucleus collisions is crucial for a correct interpretation of the J/{\psi} suppression patterns experimentally observed in heavy-ion collisions. By means of three representative sets of nuclear parton distribution, the energy loss effect in the initial state and the nuclear absorption effect in the final state are taken into account in the uniform framework of the Glauber model. A leading order phenomenological analysis is performed on J/{\psi} production cross-section ratios RW/Be(xF) for the E866 experimental data. The J/{\psi} suppression is investigated quantitatively due to the different nuclear effects. It is shown that the energy loss effect with resulting in the suppression on RW/Be(xF) is more important than the nuclear effects on parton distributions in high xF region. The E866 data in the small xF keep out the nuclear gluon distribution with a large anti-shadowing effect. However, the new HERA-B measurement is not in support of the anti-shadowing effect in the nuclear gluon distribution. It is found that the J/{\psi}-nucleon inelastic cross section {\sigma} J/{\psi} abs depends on the kinematical variable xF, and increases as xF in the region xF > 0.2. 1 Introduction

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arXiv2011

Quark energy loss in semi-inclusive deep inelastic scattering of leptons on nuclei

Semi-inclusive deep inelastic scattering on nuclear targets is an ideal tool to study the energy loss effect of an outgoing quark in a nuclear medium. By means of the short hadron formation time, the experimental data with quark hadronization occurring outside the nucleus are picked out. A leading-order analysis is performed for the hadron multiplicity ratios as a function of the energy fraction on helium, neon, and copper nuclei relative to deuteron for the various identified hadrons. It is shown that the nuclear effects on parton distribution functions can be neglected. It is found that the theoretical results considering the nuclear modification of fragmentation functions due to quark energy loss are in good agreement with the experimental data. Whether the quark energy loss is linear or quadratic with the path length is not determined. The obtained energy loss per unit length is 0.38 \pm 0.03 GeV/fm for an outgoing quark by the global fit.

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arXiv2004

Energy Loss Effect in High Energy Nuclear Drell-Yan Process

The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effect on the parton distribution as in deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep inelastic scattering experimental data, measured Drell-Yan production cross sections for 800GeV proton incident on a variety of nuclear targets are analyzed within Glauber framework which takes into account energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866.

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