Coulomb distortion effects in quasi-elastic scattering on heavy nuclei

Aste, Andreas

doi:10.1016/j.nuclphysa.2008.03.011

Cited by 8 publications

(6 citation statements)

References 64 publications

(114 reference statements)

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“…However, a reanalysis of these data (Jourdan, 1995(Jourdan, , 1996, utilizing an alternative prescription for the Coulomb corrections, concluded that there is no quenching. The analysis of the Coulomb corrections in those works was later challenged (Aste et al, 2005;Aste, 2008;Wallace and Tjon, 2008). These papers support the conclusion that quenching of the CSR occurs as reported in Ref.…”

Section: The D/u Ratio At Large Xbsupporting

confidence: 69%

Nucleon-nucleon correlations, short-lived excitations, and the quarks within

et al. 2017

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This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.

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Section: The D/u Ratio At Large Xbsupporting

confidence: 69%

Nucleon-nucleon correlations, short-lived excitations, and the quarks within

et al. 2017

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“…Inclusion of this correction yields somewhat improved agreement at low ε, but there are still clear differences remaining. For heavy nuclei and low energy scattering, there can be significant differences between the EMA result and more complete calculations [56], although the qualitative behavior is always reasonable.…”

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confidence: 90%

“…More details of the EMA and comparisons to more complete approaches, where available, are given in Ref. [55,56]. Figure 2 shows the fractional correction to the cross section in the 2nd Born approximation.…”

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confidence: 99%

Coulomb corrections in the extraction of the proton radius

Arrington

2013

J. Phys. G: Nucl. Part. Phys.

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Multi-photon exchange contributions are important in extracting the proton charge radius from elastic electron-proton scattering. So far, only diagrams associated with the exchange of a second photon have been evaluated. At the low Q 2 values relevant to the radius extraction, and especially the very low Q 2 region to be probed by proposed measurements, higher order contributions may become important. We evaluate these corrections in the Effective Momentum Approximation, which includes the Coulomb interaction to all orders, and find small corrections with a strong Q 2 dependence at low Q 2 and large scattering angles. This suggests that the higher order terms may be important in the evaluation of the proton magnetic radius.

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“…The analysis of the Coulomb corrections in those works was later challenged in Refs. [31][32][33] and quenching of the CSR over a wider range of nuclei was reported in Ref. [34].…”

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confidence: 57%

Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule

2016

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In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q| 0.5 GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.PACS numbers: 25.70.Bc, 13.40. Gp, Traditionally the nucleus is viewed as a collection of nucleons that interact via phenomenological potentials. This picture has proven successful since the establishment of the nuclear shell model and the interim has seen steady refinement, culminating today in sophisticated non-relativistic quantum-many-body approaches [1][2][3][4][5]. A key assumption of such approaches is that the internal structural properties of the nucleons which comprise a nucleus are the same as those of free nucleons. However, with the realization that quantum chromodynamics (QCD) is the fundamental theory of the strong interaction, it is natural to expect that these nucleon properties are modified by the nuclear medium [6][7][8][9]. Understanding the validity of these two viewpoints remains a key challenge for contemporary nuclear physics. Should it turn out that nucleon properties are significantly modified by the nuclear medium, this would represent a new paradigm for nuclear physics and help build a bridge between QCD and nuclei. On the other hand, if the bound nucleon is unchanged this would shed light on colour confinement in QCD and force a rethink of numerous approaches to hadron structure.Experimental evidence for explicit quark and gluon effects in nuclei remains elusive and to date the most famous example of such evidence -albeit not incontrovertible -is the EMC effect [10][11][12]. First observed in 1982 [13], the EMC effect refers to a quenching of the nuclear structure functions relative to those of a free nucleon, and demonstrates that valence quarks in a nucleus carry a smaller momentum fraction than those in a free nucleon. Numerous explanations have been proposed, ranging from nuclear structure [14][15][16][17] to QCD effects [18][19][20][21][22][23], however, no consensus has yet been reached concerning the cause of the EMC effect.Although the EMC effect is best known, the first hints of QCD effects in nuclei came from quasielastic electron scattering on nuclear targets [24][25][26]. The d...

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Coulomb distortion effects in quasi-elastic scattering on heavy nuclei

Cited by 8 publications

References 64 publications

Nucleon-nucleon correlations, short-lived excitations, and the quarks within

Nucleon-nucleon correlations, short-lived excitations, and the quarks within

Coulomb corrections in the extraction of the proton radius

Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule

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