The evolution of partons in the nuclear medium and the EMC effect

1992 ◽  
Vol 70 (2-3) ◽  
pp. 114-118
Author(s):  
Jianjun Yang ◽  
Yabo Zhu ◽  
Hongqing Shen ◽  
Guanglie Li ◽  
Jianping Shen
Keyword(s):  
Structure Function ◽  
Nuclear Structure ◽  
Motion Correction ◽  
Momentum Conservation ◽  
Evolution Model ◽  
Nuclear Medium ◽  
Dynamical Mechanism ◽  
Fermi Motion ◽  
Shadowing Effect ◽  
Emc Effect

In this paper, we present the parton evolution model and describe the dynamical mechanism of the EMC effect. The ratio of the average nuclear structure function of the nucleus 56Fe to the deuteron structure function is calculated by considering the shadowing effect and the Fermi-motion correction with nuclear momentum conservation. We find that the dynamical mechanism of the EMC effect is the evolution of a parton in the nuclear medium.

scholarly journals QCD AND QED DYNAMICS IN THE EMC EFFECT

2012 ◽  
Vol 21 (04) ◽  
pp. 1230002 ◽  
Author(s):  
LEONID FRANKFURT ◽  
MARK STRIKMAN
Keyword(s):  
Structure Function ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Momentum Conservation ◽  
Light Nuclei ◽  
Heavy Nuclei ◽  
Fermi Motion ◽  
Nucleon Wave Function ◽  
Emc Effect ◽  
Bjorken X

Applying exact QCD sum rules for the baryon charge and energy–momentum conservation we demonstrate that if the only degrees of freedom in nuclei were nucleons, the structure function of a nucleus would be the additive sum of the nucleon distributions at the same Bjorken x = AQ2/2(pA⋅q)≤0.5 up to very small Fermi motion corrections if 1/2mN x is significantly less than the nucleus radius. Hence QCD implies that the proper quantity to reveal violation of the additivity due to presence of nonnucleonic degrees of freedom in nuclei is the ratio RA(x, Q2) = (2/A)F2A(x, Q2)/F2D(x, Q2). Use of variable xp = Q2/2q0mp in the experimental studies instead of x leads to the deviation of RA(xp, Q2) from one even if the nucleus would consist only of nucleons with small momenta. Implementation of QCD dynamics accounts in the case of the light nuclei for at least a half of the deviation of RA(xp, Q2) from one for x≤0.55. In the case of heavy nuclei account of the QCD dynamics and of light-cone momentum fraction carried by Fermi, Weizsacker, Williams equivalent photons are responsible for ≈ one half the deviation of RA(x, Q2) from one at x≤0.55. We argue that direct observation of large and predominantly nucleonic short-range correlations (SRCs) in nuclei impacts strongly on the understanding of the EMC effect for x≥0.6 posing a serious challenge for most of the proposed models of the EMC effect. The data are consistent with a scenario in which the hadronic EMC effect reflects suppression of rare quark–gluon configurations in nucleons belonging to SRC appears to be the only viable. The dynamic realization of this scenario is presented in which quantum fluctuations of the nucleon wave function with x≥0.5 parton have a weaker interaction with nearby nucleons, leading to suppression of such configurations in bound nucleons and to the significant suppression of nucleon Fermi motion effects at x≥0.55 giving a right magnitude of the EMC effect. Implications of discussed effects for the analyses of the neutron structure function and nuclear parton distributions are presented. The directions for the future studies and challenging questions are outlined.

Analysis of the scale properties of nuclear structure function

1984 ◽  
Vol 1 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Liu Feng ◽  
Li Jia-rong ◽  
Liu Lian-sou
Keyword(s):  
Structure Function ◽  
Nuclear Structure ◽  
Scale Properties

scholarly journals Unveiling saturation effects from nuclear structure function measurements at the EIC

2017 ◽  
Vol 772 ◽  
pp. 607-614 ◽  
Author(s):  
Cyrille Marquet ◽  
Manoel R. Moldes ◽  
Pía Zurita
Keyword(s):  
Structure Function ◽  
Nuclear Structure ◽  
Saturation Effects

scholarly journals EFFECT DUE TO COMPOSITENESS OF NUCLEONS IN DEEP INELASTIC LEPTON NUCLEUS SCATTERING

1992 ◽  
Vol 01 (04) ◽  
pp. 809-821 ◽  
Author(s):  
BO-QIANG MA
Keyword(s):  
Structure Function ◽  
Nuclear Structure ◽  
Light Cone ◽  
Degrees Of Freedom ◽  
Structure Functions ◽  
Nucleon Structure ◽  
Nucleon Structure Function ◽  
Nucleus Scattering ◽  
Quark Structure ◽  
Nuclear Structure Functions

The off-shell behaviors of bound nucleons in deep inelastic lepton nucleus scattering are discussed in two scenarios with the basic constituents chosen to be baryon-mesons and quark-gluons respectively in light-cone formalism. It is found that when taking into account the effect due to internal quark structure of nucleons, the derived scaling variable for bound nucleons and the calculated nuclear structure functions are different from those in considering the baryon-mesons as the effective elementary constituents. This implies that the pure baryon-meson descriptions of nuclei give the inaccurate off-shell behavior of the bound nucleon structure function, thereby the quark-gluons seem to be the most appropriate degrees of freedom for nuclear descriptions.

scholarly journals A re-evaluation of the nuclear structure function ratios for D, He, 6Li, C and Ca

1995 ◽  
Vol 441 (1-2) ◽  
pp. 3-11 ◽  
Author(s):  
P. Amaudruz ◽  
M. Arneodo ◽  
A. Arvidson ◽  
B. Badelek ◽  
M. Ballintijn ◽  
...  
Keyword(s):  
Structure Function ◽  
Nuclear Structure
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