Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei

Abstract

We measured the triple coincidence A(e,e'np) and A(e,e'pp) reactions on carbon, aluminum, iron, and lead targets at Q2 > 1.5 (GeV/c)2, xB > 1.1 and missing momentum > 400 MeV/c. This was the first direct measurement of both proton-proton (pp) and neutron-proton (np) short-range correlated (SRC) pair knockout from heavy asymmetric nuclei. For all measured nuclei, the average proton-proton (pp) to neutron-proton (np) reduced cross-section ratio is about 6%, in agreement with previous indirect measurements. Correcting for Single-Charge Exchange effects decreased the SRC pairs ratio to ~ 3%, which is lower than previous results. Comparisons to theoretical Generalized Contact Formalism (GCF) cross-section calculations show good agreement using both phenomenological and chiral nucleon-nucleon potentials, favoring a lower pp to np pair ratio. The ability of the GCF calculation to describe the experimental data using either phenomenological or chiral potentials suggests possible reduction of scale- and scheme-dependence in cross section ratios. Our results also support the high-resolution description of high-momentum states being predominantly due to nucleons in SRC pairs.

arXiv commentAccepted for publication in PRL. 9 pages, 3 figures, 3 tables and supplementary materials

References in corpus (44)

• An accurate nucleon-nucleon potential with charge-independence breaking
• Modern Theory of Nuclear Forces
• Quantum Monte Carlo methods for nuclear physics
• Probing Cold Dense Nuclear Matter
• Nucleon-Nucleon Correlations, Short-lived Excitations, and the Quarks Within
• Quantum Monte Carlo Calculations with Chiral Effective Field Theory Interactions
• Momentum sharing in imbalanced Fermi systems
• Realistic Model of the Nucleon Spectral Function in Few- and Many- Nucleon Systems
• Evidence for the Strong Dominance of Proton-Neutron Correlations in Nuclei
• Tensor Forces and the Ground-State Structure of Nuclei
• Local chiral effective field theory interactions and quantum Monte Carlo applications
• Short Range Correlations and the EMC Effect
• Nucleon Effective Masses in Neutron-Rich Matter
• Modified Structure of Protons and Neutrons in Correlated Pairs
• n-p Short-Range Correlations from (p,2p + n) Measurements
• Recent observation of short range nucleon correlations in nuclei and their implications for the structure of nuclei and neutron stars
• Probing the Repulsive Core of the Nucleon-Nucleon Interaction via the 4He(e,e'pN) Triple-Coincidence Reaction
• Symmetry Energy of Nucleonic Matter With Tensor Correlations
• Feynman Graphs and Generalized Eikonal Approach to High Energy Knock-Out Processes
• New data strengthen the connection between Short Range Correlations and the EMC effect
• Exclusive Electro-Disintegration of 3He at high Q2: II. Decay Function Formalism
• The EMC Effect and High Momentum Nucleons in Nuclei
• The nuclear contacts and short range correlations in nuclei
• Selected Topics in High Energy Semi-Exclusive Electro-Nuclear Reactions
• Generalized nuclear contacts and the nucleon's momentum distributions
• Relativistic formulation of Glauber theory for A(e,e'p) reactions
• New Properties of High Momentum Distribution of Nucleons in Asymmetric Nuclei
• Color Transparency: past, present and future
• Short Range Correlations and the EMC Effect in Effective Field Theory
• The center of mass motion of short-range correlated nucleon pairs studied via the A(e,e'pp) reaction
• Probing the high momentum component of the deuteron at high Q^2
• Stylized features of single-nucleon momentum distributions
• Extracting the Mass Dependence and Quantum Numbers of Short-Range Correlated Pairs from A(e,e'p) and A(e,e'pp) Scattering
• Short-range correlations in nuclei with similarity renormalization group transformations
• Energy and momentum dependence of nuclear short-range correlations - Spectral function, exclusive scattering experiments and the contact formalism
• On the dependence of the wave function of a bound nucleon on its momentum and the EMC effect
• Single particle strength restoration and nuclear transparency in high Q^2 exclusive (e,e'p) reactions
• Scale dependence of deuteron electrodisintegration
• Factorization of exclusive electroinduced two-nucleon knockout
• Measurement of transparency ratios for protons from short-range correlated pairs
• Final-state interactions in two-nucleon knockout reactions
• Constraints on the large-x d/u ratio from electron-nucleus scattering at x>1
• The isospin and neutron-to-proton excess dependence of short-range correlations
• Momentum distributions for ${}^2$H$(e,e^{\prime }p)$

Cited by in corpus (60)

• 50 Years of Quantum Chromodynamics
• Towards Understanding Astrophysical Effects of Nuclear Symmetry Energy
• Quenching of single-particle strength from direct reactions with stable and rare-isotope beams
• Probing the core of the strong nuclear interaction
• Updated systematics of intermediate-energy single-nucleon removal cross sections
• The Present and Future of QCD
• Progress in understanding short-range structure in nuclei: an experimental perspective
• Unperturbed inverse kinematics nucleon knockout measurements with a 48 GeV/c carbon beam
• The islands of shape coexistence within the Elliott and the proxy-SU(3) Models
• Neutrino event generators: foundation, status and future
• Short-range correlation physics at low RG resolution
• Revealing the short-range structure of the "mirror nuclei" ${}^3$H and ${}^3$He
• Influence of the neutron-skin effect on nuclear isobar collisions at RHIC
• Neutron valence structure from nuclear deep inelastic scattering
• Probing short-range correlations in the deuteron via incoherent diffractive $J/\psi$ production with spectator tagging at the EIC
• Electron scattering on $\mathbf{A}=3$ nuclei from quantum Monte Carlo based approaches
• Nucleon-nucleon correlations and the single-particle strength in atomic nuclei
• Neutrinoless double-beta decay: combining quantum Monte Carlo and the nuclear shell model with the generalized contact formalism
• Generalized Contact Formalism Analysis of the ${}^4$He$(e,e^{\prime }pN)$ Reaction
• The Entanglement Entropy between Short Range Correlations and the Fermi Sea in Nuclear Structure
• Extracing the number of short-range corerlated nucleon pairs from inclusive electron scattering data
• Probing few-body nuclear dynamics via 3H and 3He (e,e'p)pn cross-section measurements
• Comparing proton momentum distributions in $A=2$ and 3 nuclei via ${}^2$H ${}^3$H and ${}^3$He $(e,e^{\prime }p)$ measurements
• Densities and momentum distributions in A <=12 nuclei from chiral effective field theory interactions
• Isospin composition of the high-momentum fluctuations in nuclei from asymptotic momentum distributions
• Sub-threshold $J/\psi$ and ${\rm Y}$ Production in $\gamma A$ Collisions
• Measurement of Nuclear Transparency Ratios for Protons and Neutrons
• Nuclear Spectroscopy with Heavy Ion Nucleon Knockout and (p,2p) Reactions
• A quantum Monte Carlo based approach to intranuclear cascades
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• Phase-space distributions of nuclear short-range correlations
• Searching for three-nucleon short-range correlations
• Probing the Deuteron at Very Large Internal Momenta
• Systematic reduction of the proton-removal cross section in neutron-rich medium-mass nuclei
• Embedding short-range correlations in relativistic density functionals through quasi-deuterons
• Nucleon momentum distribution of ${}^{56}\text{Fe}$ from the axially deformed relativistic mean-field model with nucleon--nucleon correlations
• Short range correlations in the extended quantum molecular dynamics model
• Measuring Recoiling Nucleons from the Nucleus with the Electron Ion Collider
• Gluonic Probe for the Short Range Correlation in Nucleus
• High-resolution momentum distributions from low-resolution wave functions
• Nucleon-Nucleon Short-Ranged Correlations, $\beta$ Decay and the Unitarity of the CKM Matrix
• The quasi-deuteron model at low RG resolution
• Short-range correlations and momentum distributions in mirror nuclei 3H and 3He
• Proton-proton momentum correlation function as a probe of the high momentum tail of the nucleon momentum distribution
• The Mass of Short-Range Correlated Nucleon
• Review of opportunities at the HESR-Collider with PANDA at FAIR
• Studying Short-Range Correlations with Real Photon Beams at GlueX
• Discovery vs. Precision in Nuclear Physics- A Tale of Three Scales
• Nucleon Short-Range Correlations and High-Momentum Dynamics: Implications on the Equation of State of Dense Matter
• Isospin-symmetry implications for nuclear two-body distributions and short-range correlations
• Nuclear three-body short-range correlations in coordinate space
• Observing short-range correlations in nuclei through ${\rho }^0$ photo-production
• On nuclear short-range correlations and the zero-energy eigenstates of the Schrodinger equation
• Tri-meson state $\bar{\mathbf{B}}{\bar{\mathbf{B}}}^{\ast }{\bar{\mathbf{B}}}^{\ast }$
• The European Muon Collaboration effect from short-range correlated nucleons in a nucleon swelling model
• Experimental Study of Bremsstrahlung Gamma Ray Emission and Short-Range Correlations in ${}^{124}$Sn+${}^{124}$Sn Collisions at 25 MeV/u
• Predicted Measurements of the Tensor-to-Scalar Transition in the CLAS12 Nuclear Targets Experiment
• Precision measurements of A=3 nuclei in Hall B
• Impact of new results from the ultraperipheral collision on modeling the proton and neutron emission in photon-induced nuclear processes
• Nucleon momentum distributions of complex nuclei from inclusive electron scattering