We study the prospects of using femtoscopic low-momentum correlation measurements at the Large Hadron Collider to access properties of the J/psi-nucleon interaction. The QCD multipole expansion in terms of the J/psi chromopolarizability relates the forward scattering amplitude to a key matrix element to the origin of the nucleon mass problem, the average chromoelectric gluon distribution in the nucleon. We use information on the J/psi-nucleon interaction provided by lattice QCD simulations and phenomenological models to compute J/psi-nucleon correlation functions. The computed correlation functions show clear sensitivity to the interaction, in particular to the J/psi chromopolarizability.
Charmonium-nucleon femtoscopy as a possible probe of the nucleon gravitational form factor
Center for Nuclear Study (CNS), University of Tokyo（东京大学核研究中心）；Advanced Science Research Center, Japan Atomic Energy Agency (JAEA)（日本原子能机构先进科学研究）；Research Center for Nuclear Physics (RCNP), Osaka University（大阪大学核物理研究中心）；Center for Fundamental Physics, School of Mechanics and Physics, Anhui University of Science and Technology（安徽理工大学力学与物理学院基础物理中心）
From hyperon--nucleon interactions to deuteron--hyperon femtoscopy
Helmholtz Research Academy Hesse for FAIR (HFHF), GSI Helmholtz Center for Heavy Ion Physics（黑森亥姆霍兹FAIR研究学院（HFHF），GSI重离子物理中心）；Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität（约翰·沃尔夫冈·歌德大学理论物理研究所）
Shedding Light on (Anti-)nuclei Production with Pion-Nucleus Femtoscopy
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University（核物理与离子束应用（教育部）重点实验室，现代物理研究所，复旦大学）；Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University（上海理论核物理研究中心，国家自然科学基金委员会与复旦大学）；Cyclotron Institute and Department of Physics and Astronomy, Texas A&M University（回旋加速器研究所及物理与天文学系，德州农工大学）；School of Physics, East China Normal University（物理与电子科学学院，华东师范大学）
Universidad de Valencia-CSIC（瓦伦西亚大学-西班牙国家科学研究委员会）；IFIC, Centro Mixto Universidad de Valencia-CSIC（瓦伦西亚大学-CSIC混合中心IFIC）；Instituto de Física Corpuscular, Centro Mixto Universidad de Valencia-CSIC（瓦伦西亚大学-CSIC混合中心粒子物理研究所）
本文提出相对论性动量空间框架计算耦合道飞米尺度关联函数，发现 $D\pi$ 和 $D^*\pi$ 系统理论结果与 ALICE 实验提取不一致，源于实验假设关联函数在高动量达到 1 的错误，需重新分析数据以确立飞米尺度关联函数为可靠定量工具。
We present an alternative interpretation for the dynamical origin of the P11 nucleon resonances, which results from the dynamical coupled-channels analysis at Excited Baryon Analysis Center of Jefferson Lab. The results indicate the crucial role of the multichannel reaction dynamics in determining the N^* spectrum.
By using the soft pion theorem in the inclusive reactions, soft pions' contribution to the structure function $F_2$ in the nucleon is estimated. It is shown that this contribution produces such a large flavor asymmetry in the light sea quark distributions that it gives about $30\sim 50 %$ of the NMC deficit in the Gottfried sum.
Atomic nuclei are the core of everything we can see. At the first level of approximation, their atomic weights are simply the sum of the masses of all the nucleons they contain. Each nucleon has a mass $m_N \approx 1\,$GeV, i.e. approximately 2000-times the electron mass. The Higgs boson produces the latter, but what produces the nucleon mass? This is the crux: the vast bulk of the mass of a nucleon is lodged with the energy needed to hold quarks together inside it; and that is supposed to be explained by quantum chromodynamics (QCD), the strong-interaction piece within the Standard Model. Thi…
I explain the current status of parton-distribution-function (PDF) studies and future experimental prospects on their determinations. First, unpolarized PDFs of the nucleon are introduced as a field of precision QCD physics including higher-order $α_s$ corrections. Second, nuclear PDFs and polarized nucleonic PDFs are discussed. Third, the determination of fragmentation functions is explained. Forth, the three-dimensional (3D) structure functions are discussed in connection with the origin of the nucleon spin and gravitational form factors of hadrons. By the 3D structure functions, gravitation…
It is often claimed that 98% of the nucleon mass is generated by quantum chromodynamics. The decomposition of the nucleon mass based on the trace of the energy-momentum tensor suggests that gluons play by far a dominant role. About 25 years ago, Ji proposed another decomposition based on the energy component of the energy-momentum tensor, leading to a quite different picture. Recently, we critically revisited these decompositions and argued that both overlooked pressure effects. In particular we showed that Ji's decomposition, although mathematically correct, makes little sense from a physical…
We calculate the next-to-leading order perturbative corrections to the SVZ sum rules for the coupling f_N, the nucleon leading twist wave function at the origin. The results are compared to the established Ioffe sum rules and also to lattice QCD simulations.
We show that two almost degenerate poles near the $πΔ$ threshold and the next higher mass pole in the $P_{11}$ partial wave of $πN$ scattering evolve from a single bare state through its coupling with $πN$, $ηN$ and $ππN$ reaction channels. This finding provides new information on understanding the dynamical origins of the Roper $N^*(1440)$ and $N^*(1710)$ resonances listed by Particle Data Group. Our results for the resonance poles in other $πN$ partial waves are also presented.
Apart from the quark and gluon kinetic and potential energies, the nucleon mass includes a novel energy of pure quantum origin resulting from anomalous breaking of scale symmetry. We demonstrate the effects of this quantum anomalous energy (QAE) in QED, as well as in a toy 1+1 dimensional non-linear sigma model where it contributes non-perturbatively, in a way resembling the Higgs mechanism for the masses of matter particles in electro-weak theory. The QAE contribution to the nucleon mass can be explained using a similar mechanism, in terms of a dynamical response of the gluonic scalar field t…
Using the Euclidean path-integral formulation for the hadronic tensor, we show that the violation of the Gottfried sum rule does not come from the disconnected quark-loop insertion. Rather, it comes from the connected (quark line) insertion involving quarks propagating in the backward time direction. We demonstrate this by studying sum rules in terms of the scalar and axial- vector matrix elements in lattice gauge calculations. The effects of eliminating backward time propagation are presented.
The pion-nucleon sigma term is a quantity involved in many important aspects of particle and nuclear physics. In this review I show its origin and how it is connected to important questions as the origin of mass of the ordinary matter, studies of dark matter detection and nucleosynthesis. I mention the most common methods used to obtain the sigma term, and comment on the extracted values. As it is shown, the accepted value of the sigma term has been moving from relatively low ($\sim 40$ MeV) to larger ones ($\sim 60$ MeV) until today, where this controversy still persist.
The origin of weakly-bound nuclear clusters in hadronic collisions is a key question to be addressed by heavy-ion collision (HIC) experiments. The measured yields of clusters are approximately consistent with expectations from phenomenological statistical hadronisation models (SHMs), but a theoretical understanding of the dynamics of cluster formation prior to kinetic freeze out is lacking. The competing model is nuclear coalescence, which attributes cluster formation to the effect of final state interactions (FSI) during the propagation of the nuclei from kinetic freeze out to the observer. T…
We demonstrate that perturbative QCD leads to positive 3D parton--parton correlations inside nucleon explaining a factor two enhancement of the cross section of multi-parton interactions observed at Tevatron at $x_i\ge 0.01$ as compared to the predictions of the independent parton approximation. We also find that though perturbative correlations decrease with $x$ decreasing, the nonperturbative mechanism kicks in and should generate correlation which, at $x$ below $10^{-3}$, is comparable in magnitude with the perturbative one for $x\sim 0.01$.
We derive a relation for the axial-coupling constants of the nucleon and spin-3/2 baryons including the $Δ(1232)$ with the use of an $SU(2)_R\times SU(2)_L$ invariant Lagrangian. Therein the nucleon belongs to the fundamental representation of the chiral group, while the spin-3/2 baryons belong to higher-dimensional representations $(1,\half)\oplus (\half,1)$. The resulting relation reproduces the one derived from the generalized Adler-Weisberger (GAW) sum rule for the forward $πN$ scattering. We clarify the origin of the GAW sum rule for the nucleon and $Δ$ by taking into account both the gro…
Chiral theories with spontaneous symmetry breaking such as the Nambu-Jona-Lasinio (NJL) model lead to the existence of a scalar mode. We present in a detailed manner how the corresponding low momentum effective lagrangian involving the scalar field can be constructed starting from the NJL model. We discuss the relevance of the scalar mode for the problem of the nuclear binding and saturation. We show that it depends on the nucleon mass origin with two extreme cases. If this origin is entirely due to confinement the coupling of this mode to the nucleons vanishes, making it irrelevant for the nu…
Origin of the nucleon gravitational form factor $B_N(t)$: Exposition in light-front holographic QCD
University of Science and Technology of China（中国科学技术大学）；Indian Institute of Technology Kanpur（坎普尔印度理工学院）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Nuclear Science and Technology, University of Chinese Academy of Sciences（中国科学院大学核科学与技术学院）
Starting with the VMD parametrization of the electric and magnetic nucleon form factors, which are saturated just by the ground state vector-mesons rho, omega and phi, then aplying the strict OZI rule and the asymptotic behaviour of form factors as predicted by quark model of hadrons, the famous one parameter dipole formula is derived. By its comparison with space-like data up to t = -5 GeV^2 the most optimal value of the parameter under consideration is determined. Finaly, charge and magnetization distributions in proton and neutron are predicted.
In hydrodynamical modeling of heavy-ion collisions, the initial-state spatial anisotropies are translated into momentum anisotropies of the final-state particle distributions. Thus, understanding the origin of the initial-state anisotropies and their uncertainties is important before extracting specific QCD matter properties, such as viscosity, from the experimental data. In this work we review the wounded nucleon approach based on the Monte Carlo Glauber model, charting in particular the uncertainties arising from modeling of the nucleon-nucleon interactions between the colliding nucleon pair…
Recent data for the slope of the EMC-ratio in the intermediate $x$-region for {\em light} nuclei, with $3 \leq A \leq 12$, have the potential to shed new light on the origin of the EMC effect. Here we study the role of nuclear binding using the scaling variable ${\tilde y}$, best suited to take into account this effect, and the understanding of the average nucleon removal energies, $\bar{E}$, provided by state-of-the-art calculations based on nuclear many body theory. We find an excellent correlation between the new EMC data at $x \sim 0.5$ and $\bar{E}$ for nuclei with $A$ from 3 to $\infty$,…
The original version of this paper commented on a paper by Jaffe, Jin, and Tang (hep-ph/9710561). That paper has been revised, and my original comment no longer applies to the revised version. The original version of my comment (hep-ph/9801217v1) provides a simple argument that two-particle correlations in parity-invariant fragmentation cannot provide a measurement of the helicity of the fragmenting quark.
We study the three nucleon force in the triton channel using dynamical clover fermion lattice QCD. The Nambu-Bethe-Salpeter wave function is utilized to obtain the potentials among three nucleons. Since the straightforward calculation is prohibitively expensive, two different frameworks are developed to meet the challenge. In the first method, we study the effective two nucleon potentials in the three nucleon system, where the differences between the effective two nucleon potentials and the genuine two nucleon potentials correspond to the three nucleon system effect, part of which is originate…
The light-quark mass dependence of the nucleon axial isovector charge ($g_A$) has been studied up to next-to-next-to-leading order, $O(p^4)$, in relativistic chiral perturbation theory using extended-on-mass-shell renormalization, without and with explicit $Δ(1232)$ degrees of freedom. We show that in the $Δ$-less case, at this order, the flat trend of $g_A (M_π)$ exhibited by state-of-the-art lattice QCD (LQCD) results cannot be reproduced using low energy constants (LECs) extracted from pion-nucleon elastic and inelastic scattering. A satisfactory description of these LQCD data is only achie…
The QCD sum rule method is applied to derive a formula for the rho, omega, phi meson-nucleon spin-isospin-averaged scattering lengths $a_{ρ,ω,ϕ}$. We found that the crucial matrix elements are $\langle\bar{q}γ_μD_νq\rangle_N$ ($q=u,d$) (twist-2 nucleon matrix element) for $a_{ρ,ω}$ and $m_s\langle\bar{s}s\rangle_N$ for $a_ϕ$, and obtained $a_ρ=0.14\pm 0.07$ fm, $a_ω=0.11\pm 0.06$ fm and $a_ϕ=0.035\pm 0.020$ fm. These small numbers originate from a common factor $1/(m_N+m_{ρ,ω,ϕ})$. Our result suggests a slight increase ($< 60$ MeV for $ρ$, $ω$, and $<15$ MeV for $ϕ$) of the effective mass of t…
Castillejo-Dalitz-Dyson (CDD) poles are known to be connected with bound states and resonances. We discuss a new type of CDD pole associated with primitives i.e., poles of the P matrix that correspond to zeros of the D function on the unitary cut. Low's scattering equation is generalized for amplitudes with primitives. The relationship between the CDD poles and the primitives is illustrated by a description of the S-wave nucleon-nucleon phase shifts.
We apply the approximating chiral quark model. This chiral quark model is based on an effective Lagrangian which the interactions between quarks via sigma and pions mesons. The field equations have been solved in the mean field approximation for the hedgehog baryon state. Good results are obtained for nucleon properties in comparison with original model.
The generalized Gerasimov-Drell-Hearn (GDH) sum rule is understood based on the polarized parton distributions of the proton with the higher twist contributions. A simple parameterized formula is proposed to clearly present the contributions of different components in proton to $Γ_1^p(Q^2)$. We find that the contribution of quark helicity to $Γ_1^p(Q^2)$ is almost constant ($\sim 0.123$); the twist-4 effect dominates the suppression of $Γ_1^p(Q^2)$ at $Q^2<3GeV^2$, while the twist-6 effect arises a dramatic change of $Γ_1^p(Q^2)$ at $Q^2<0.3 GeV^2$, it implies a possible extended objects with …
A lecture given at the International School Seminar on {\sl Hadrons and Nuclei from QCD}, Tsuruga-Vladivostok-Sapporo, August-September, 1993. A realistic hyperon ($Y$)-nucleon ($N$) interaction based on the quark model and the one-boson-exchange potential is constructed. The Nijmegen potential model D with the SU(3) flavor symmetry is modified with a quark exchange interaction at the short-distance, which replaces the short-range repulsive core in the original model. The flavor-spin dependences of the short-range repulsion are qualitatively different from the original hard-core potential. We …
In a recent analysis of the world data on polarized DIS, Blumlein and Bottcher conclude that there is no evidence for higher twist contributions, in contrast to the claim of the LSS group, who find evidence for significant higher twist effects. We explain the origin of the apparent contradiction between these results.
The chiral SU(3) quark model is extended to include the coupling between the quark and vector chiral fields. The one-gluon exchange (OGE) which dominantly governs the short-range quark-quark interaction in the original chiral SU(3) quark model is now nearly replaced by the vector-meson exchange. Using this model, the isospin I=0 and I=1 kaon-nucleon S, P, D, F wave phase shifts are dynamically studied by solving the resonating group method (RGM) equation. Similar to those given by the original chiral SU(3) quark model, the calculated results for many partial waves are consistent with the exper…
A transport theory is developed on the quark level to describe nucleon--nucleon collisions. We treat the strong interaction effectively by the Friedberg-Lee model both in its original and in its modified confining version. First we study the stability of the static three-dimensional semiclassical configuration, then we present results of the time evolution given by a Vlasov equation for the quarks coupled to a Klein-Gordon equation for the mean field. We find at higher energies that the nucleons are almost transparent, whereas at lower energies we observe a substantial interaction. At very low…
We demonstrate that measurement of tagged structure functions of the deuteron in (e,e'N) semi-inclusive reactions can discriminate between different hypotheses on the origin of the nuclear EMC effect. By choosing extreme backward kinematics for the spectator nucleon to minimize effects from the deuteron wave function and final state interactions, one can isolate the modifications in the structure of the bound nucleon within the impulse approximation. The same reaction can be used to extract the large-x neutron to proton structure function ratio.
The visible universe - it is the universe of nucleons and electrons. The appearance of nucleon mass is caused by the violation of chiral symmetry in quantum chromodynamics (QCD). For this reason, the experiments on high energy accelerators cannot shed light on the origin of the matter in the visible universe. The origin of the mass of matter will be clarified, when the mechanism of chiral symmetry violation in QCD will be elucidated.
We analytically prove that the existence of the delta-function singularity in the chirally-odd twist-3 distribution $e(x)$ of the nucleon is inseparably connected with the nonvanishing quark condensate as a signal of the spontaneous chiral symmetry breaking of the QCD vacuum. This singularity in $e(x)$, which would be observed as a sizable violation of the 1st moment sum rule, is then interpreted as giving a very rare case that the nontrivial vacuum structure of QCD manifests in an observable of a localized QCD excitation, i.e. the nucleon.
Excited states of the nucleon were predicted by Wentzel already in 1940. Wentzel showed that such kind of states can be derived from models of meson field theory if they are treated above a certain coupling strength. In particular for a pseudo-scalar meson field theory such kind of states were derived by Pauli and Dancoff in 1942 with equal amount of spin and isospin. They can be understood as arising from excitation of the pionic cloud of the nucleon by which the main part of nuclear forces also is coming out. The excitation of these states also is the mechanism by which the pion-nucleon reso…
In hydrodynamicalmodeling of heavy-ion collisions the initial state spatial anisotropies translate into momentum anisotropies of the final state particle distributions. Thus, understanding the origin of the initial anisotropies and quantifying their uncertainties is important for the extraction of specific QCD matter properties, such as viscosity, from the experimental data. In this work we study the wounded nucleon approach in the Monte Carlo Glauber model framework, focusing especially on the uncertainties which arise from the modeling of the nucleon-nucleon interactions between the collidin…
Most of the mass of everyday objects resides in atomic nuclei; the total of the electrons' mass adds up to less than one part in a thousand. The nuclei are composed of nucleons---protons and neutrons---whose nuclear binding energy, though tremendous on a human scale, is small compared to their rest energy. The nucleons are, in turn, composites of massless gluons and nearly massless quarks. It is the energy of these confined objects, via $M=E/c^2$, that is responsible for everyday mass. This article discusses the physics of this mechanism and the role of lattice gauge theory in establishing its…
After scattering off nuclei in the Sun, dark matter particles can be gravitationally captured by the Sun, accumulate in the Sun's core and annihilate into Standard Model particles. Neutrinos originating from these annihilations can be detected by the IceCube Neutrino Observatory, located at the South Pole. Due to the non-observation of these neutrinos, constraints on the standard spin-dependent and spin-independent dark matter-nucleon scattering cross sections have been placed. Based on these constraints, we present upper limits on the coupling constants of the non-relativistic effective theor…
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 …
The D-term is a particle property defined, similarly to the mass and spin, through matrix elements of the energy-momentum tensor. It is currently not known experimentally for any particle, but the D-term of the nucleon can be inferred from studies of hard-exclusive reactions. In this work we show that the D-term of a spin-1/2 fermion is of dynamical origin: it vanishes for a free fermion. This is in pronounced contrast to the bosonic case where already a free spin-0 boson has a non-zero intrinsic D-term as shown in an accompanying work. We illustrate in two simple models how interactions gener…
Hadron cascade model is an essential part of Monte Carlo neutrino event generators that governs final state interactions of knocked-out nucleons and produced pions. It is shown that such model enriched with physically motivated modifications of nucleon-nucleon cross section and incorporation of nuclear correlation effects is able to reproduce experimental nuclear transparency data. Uncertainty of nucleon final state interactions effects is estimated and applied to recent neutrino-nucleus cross section measurements that include an outgoing proton in the experimental signal. Conclusions are draw…
Nucleon electric dipole moments originating from strong CP-violation are being calculated by several groups using lattice QCD. We revisit the finite volume corrections to the CP-odd nucleon matrix elements of the electromagnetic current, which can be related to the electric dipole moments in the continuum, in the framework of chiral perturbation theory up to next-to-leading order taking into account the breaking of Lorentz symmetry. A chiral extrapolation of the recent lattice results of both the neutron and proton electric dipole moments is performed, which results in $d_n=(-2.7\pm1.2)\times1…
The Drell-Yan cross section ratios, $σ(p+d)/σ(p+p)$, measured in Fermilab E866, have led to the first determination of $\bar d(x) / \bar u(x)$, $\bar d(x) - \bar u(x)$, and the integral of $\bar d(x) - \bar u(x)$ for the proton over the range $0.02 \le x \le 0.345$. The E866 results are compared with predictions based on parton distribution functions and various theoretical models. The relationship between the E866 results and the NMC measurement of the Gottfried integral is discussed. The agreement between the E866 results and models employing virtual mesons indicates these non-perturbative p…
