We show that the empirical linear relation between the magnitude of the EMC effect in deep inelastic scattering on nuclei and the short range correlation scaling factor $a_2$ extracted from high-energy quasi-elastic scattering at $x\ge 1$ is a natural consequence of scale separation and derive the relationship using effective field theory. While the scaling factor $a_2$ is a ratio of nuclear matrix elements that individually depend on the calculational scheme, we show that the ratio is independent of this choice. We perform Green's function Monte Carlo calculations with both chiral and Argonne-Urbana potentials to verify this and determine the scaling factors for light nuclei. The resulting values for $^3$He and $^4$He are in good agreement with experimental values. We also present results for $^9$Be and $^{12}$C extracted from variational Monte Carlo calculations.
The relative contributions to the valence nuclear EMC effect in the deuteron arising from off-shell effects and Fermi motion are examined in models which include nuclear binding and off-shell effects. Contrary to expectations, the effect of Fermi motion overwhelms the off-shell effects for nucleons in short-range correlations (SRCs), calling into question the hypothesized causal connection between SRCs and the EMC effect.
最近的EMC效应测量和核标度测量的结果都归因于局部核密度效应，而不是体核系统的属性。这使我们观察到在0.3 < x_< 0.7 EMC data scale as the ratio of the x_B >B1的核标度平台中斜率的比值.利用这种关联，我们发展了一个唯象关系，再现了从3He到56Fe核的EMC效应的一般趋势和特征。
The EMC effect in deuterium and helium-3 is studied using a convolution formalism that allows isolating the impact of high-momentum nucleons in short-ranged correlated (SRC) pairs. We assume that the modification of the structure function of bound nucleons is given by a universal (i.e. nucleus independent) function of their virtuality, and find that the effect of such modifications is dominated by nucleons in SRC pairs. This SRC-dominance of nucleon modifications is observed despite the fact that the bulk of the nuclear inelastic scattering cross-section comes from interacting with low-momentu…
In this paper, we examine the hypothesis that the nuclear EMC effect comes merely from the N-N SRC pairs inside the nucleus and that the properties of N-N SRC pair are universal among the various nuclei, using the conventional $x$-rescaling model for the EMC effect. With the previously determined effective mass of the short-range correlated nucleon and the number of N-N SRC pairs estimated, we calculate the EMC effect of various nuclei within the $x$-rescaling approach. From our calculations, the nuclear EMC effect due to the mass deficits of the SRC nucleons is not enough to reproduce the obs…
In the 35 years since the European Muon Collaboration announced the astonishing result that the valence structure of a nucleus was very different from that of a free nucleon, many explanations have been suggested. The first of the two most promising explanations is based upon the different effects of the strong Lorentz scalar and vector mean fields known to exist in a nucleus on the internal structure of the nucleon-like clusters which occupy shell model states. The second links the effect to the modification of the structure of nucleons involved in short-range correlations, which are far off …
Gamow-Teller transitions in nuclei tell us that the nucleon's axial charge $g_A^{(3)}$ is quenched in large nuclei by about 20%. This result tells us that the spin structure of the nucleon is modified in nuclei and disfavours models of the medium dependence of parton structure based only on nucleon short range correlations in nuclei. For polarized photoproduction the Gerasimov-Drell-Hearn integral is expected to be strongly enhanced in medium.
Diquark formation across a short-range nucleon-nucleon pair is proposed as the underlying QCD physics of short-range correlations (SRC) in nuclei. SRC pairs have been proposed as the cause of distorted quark behavior in nuclei; experimentally observed quark momentum distribution distortions termed the EMC effect. The strong spatial overlap of SRC pairs brings nucleon constituents within range of inter-nucleon QCD potentials and any bonds formed - such as the diquark bond - affects their distributions. In this SRC model, diquarks form in the $\rm 3_C \otimes 3_C \rightarrow \bar{3}_C$ channel o…
Testing a Linear Relation: Short-Range Correlations and the EMC Effect for Gluons and Quarks in Nuclei
Frontiers Science Center for Rare Isotopes, and School of Nuclear Science and Technology, Lanzhou University（兰州大学前沿科学中心稀有同位素及School of Nuclear Science and Technology）；INPAC, Key Laboratory for Particle Astrophysics and Cosmology (MOE), Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院粒子天体物理与宇宙学教育部重点实验室上海粒子物理与宇宙学重点实验室）；School of Physics and Optoelectronic Engineering, Shandong University of Technology（山东理工大学物理与光电工程学院）；Department of Physics, School of Science, Tianjin University（天津大学理学院物理学系）
The CLAS collaboration at Jefferson Laboratory has compared nuclear parton distributions for a range of nuclear targets and found that the EMC effect measured in deep inelastic lepton-nucleus scattering has a strongly "isophobic" nature. This surprising observation suggests short-range correlations between neighboring $n$ and $p$ nucleons in nuclear wavefunctions that are much stronger compared to $p-p$ or $n-n$ correlations. In this paper we propose a definitive experimental test of the nucleon-nucleon explanation of the isophobic nature of the EMC effect: the diffractive dissociation on a nu…
应用重子电荷和能量动量的精确QCD求和规则，我们证明了如果核子是核波函数的唯一自由度，则核的结构函数将是在相同的Bjorken x = AQ^2/2（p_Aq）0.05处核子分布的加和< 0.5 up to very small Fermi motion corrections if x>.因此，EMC比与1的差异揭示了原子核中存在非核子自由度。利用精确的QCD求和定则，我们证明了实验研究中所用的比值R_A（x_p，Q_2），其中x_p = Q_2/2q_0m_p，即使在一个核只由小动量核子组成的情况下，也偏离1。与x_p图相比，使用Bjorken x图可使R_A（x，Q^2）进一步减小。核库仑场的洛伦兹变换明确地给出了等效光子对核部分子波函数光子分量的相干贡献。对于A~200，光子携带原子核光动量的~0.0065部分，这几乎补偿了数据分析在Bjorken x和x_p方面的差异。直接观测原子核中大的、主要是核子的短程关联，对x>0.6的EMC效应的大多数模型提出了严重的挑战。这些数据与强子EMC效应反映核子间相互作用的涨落的情形是一致的，这种涨落是由于相互作用核子中颜色分布的涨落引起的。这种情况的动态实现是这样的模型，其中x > 0.5的3q（3qg）组态与附近核子的相互作用较弱，导致抑制这种组态，从而给出正确的EMC效应。展望了未来的研究方向和挑战性问题。
We investigate the gluonic probe to the nucleon-nucleon short range correlation (SRC) in nucleus through heavy flavor production in deep inelastic scattering (DIS). The relevant EMC effects of $F_2^{c\bar c}$ structure function will provide a universality test of the SRCs which have been extensively studied in the quark-channel. These SRCs can also be studied through the sub-threshold production of heavy flavor in $eA$ collisions at the intermediate energy electron-ion collider, including open Charm and $J/ψ$ ($Υ$) production.
We investigate charged-current neutrino-nucleus deep inelastic scattering with particular interests in relationship of short range correlation (SRC) and EMC effect. The structure functions $F^A_2(x,Q^2)$, $x F^A_3(x,Q^2)$ and ratios of differential cross sections are presented where the nuclei $A$ are chosen to be carbon, iron and lead. We propose a kind of universal modification functions which would provide a nontrivial test of SRC universality on the platform of neutrino-nucleus scattering and improve our understanding of nucleon structure substantially.
We present an overview of Short-Range Correlations (SRC) studies using the inclusive measurement of the electron scattering off nuclei. A brief introduction of the origin of the SRC is given, followed by the survey of the two-nucleon SRC (2N-SRC) study and its interesting connection to the EMC effect. A discussion of the three-nucleon SRC study (3N-SRC) measured by the Jefferson Lab's Hall B and Hall C experiments which showed contradictory results is given and, most importantly, we report a new result from the Hall A E08-014 experiment which was dedicated on studying 3N-SRC. Our high precisio…
Short-Range Correlation Scaling of Nuclear Parton Modifications: Consistency Tests and Recoil-Tagged Charm-Production DIS
Lanzhou University（兰州大学）；Shanghai Jiao Tong University（上海交通大学）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；Tianjin University（天津大学）
We calculate the baryon factorial cumulants assuming arbitrary short-range correlations and the global baryon number conservation. The general factorial cumulant generating function is derived. Various relations between factorial cumulants subjected to baryon number conservation and the factorial cumulants without this constraint are presented. We observe that for $n$-th factorial cumulant, the short-range correlations of more than $n$ particles are suppressed with the increasing number of particles. The recently published [1] relations between the cumulants in a finite acceptance with global …
We calculate the baryon number cumulants within acceptance with short-range correlations and global baryon number conservation in terms of cumulants in the whole system without baryon conservation. We extract leading and next-to-leading order terms of the large baryon number limit approximation. Our results extend the findings of Refs. [1,2]. These approximations are checked to be very close to the exact results.
