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DOE OSTI2018

Δ isobars and nuclear saturation

In this paper, we construct a nuclear interaction in chiral effective field theory with explicit inclusion of the $\mathrm{{\Delta}}$-isobar $\mathrm{{\Delta}}(1232)$ degree of freedom at all orders up to next-to-next-to-leading order (NNLO). We use pion-nucleon (${\pi}N$) low-energy constants (LECs) from a Roy-Steiner analysis of ${\pi}N$ scattering data, optimize the LECs in the contact potentials up to NNLO to reproduce low-energy nucleon-nucleon scattering phase shifts, and constrain the three-nucleon interaction at NNLO to reproduce the binding energy and point-proton radius of $^{4}\mathrm{He}$. For heavier nuclei we use the coupled-cluster method to compute binding energies, radii, and neutron skins. We find that radii and binding energies are much improved for interactions with explicit inclusion of $\mathrm{{\Delta}}(1232)$, while $\mathrm{{\Delta}}$-less interactions produce nuclei that are not bound with respect to breakup into ${\alpha}$ particles. Finally, the saturation of nuclear matter is significantly improved, and its symmetry energy is consistent with empirical estimates.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2012

Breakup of deuterons on tritons

The breakup reaction T (d, p)nt at the projectile deuteron energy of 36.9 MeV was studied theoretically and experimentally. The measured inclusive spectra and angular distributions of product protons are presented. A theoretical description of the reaction in question is based on the microscopic nuclear-diffractionmodel and on the theory of resonance processes. It is shown that, in T (d, p) processes, a significant role is played not only by quasifree processes involving final-state interaction that are considered in the diffraction approximation but also by the production of {sup 4}H* and {sup 4}He* resonance states. The experimental results obtained in the present study for the angular and energy distributions of final-state particles can be satisfactorily interpreted with allowance for these resonances. It is shown that only upon taking into account two {sup 4}H* resonances do the calculated spectra of protons from T (d, p) reactions appear to be in good numerical agreement with experimental data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2012

Extraction of pion non-perturbative fragmentation functions in ZM-VFNS

We present pion non-perturbative fragmentation functions (non-pFFs) at next-to-leading order (NLO) obtained through a global fit to electron-positron annihilation data from CERN LEP1, SLAC SLC, DESY and KEK, using zero-mass variable-flavor-number scheme. We apply the obtained non-pFFs to predict the scaled-energy distribution of {pi}{sup {+-}} inclusively produced in top-quark decays. The results are in good agreement with the available theoretical models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Exotic structure in light neutron-rich nuclei

In this presentation I discussed two subjects. One is the persistence of threefold symmetry in the ground state of {sup 12}C. Recently D{sub 3h} symmetry has been established in {sup 12}C, which reflects the geometric symmetry of the three α particles. Although the spin-orbit interaction plays a significant role and this interaction breaks the α clusters, we show that threefold symmetry of {sup 12}C is still there. We use AQCM approach and discuss that inclusion of spin-orbit interaction, which is absent in the conventional microscopic α cluster models, is possible keeping the threefold symmetry. The second subject is the appearance of rod shape in C isotopes, which has been investigated in the framework of the cranking covariant density functional theory. The relationship between the stability of such states and the spin and isospin degrees of freedom is discussed; adding valence neutrons and rotating the system. These two effects stabilize the rod shape, and in addition, their coherent effect has been found; the σ-orbits (parallel to the symmetry axis) of the valence neutrons, which enhances the rod shape, is lowered by the rotation of the system, and this σ-orbit pulls down the single particle energies of protons with linear configuration owing to the proton-neutron interaction effect.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2018

Low Phosphorus Availability Decreases Susceptibility of Tropical Primary Productivity to Droughts

Large uncertainties in the susceptibility of tropical forest productivity to precipitation changes hamper climate change projection. Interactions between the availabilities of water and phosphorus could theoretically either increase or decrease the susceptibility of tropical gas exchange to variation of precipitation. The inclusion of phosphorus-water interactions in a land surface model reduces the coefficient of variance, a measure of variability, of biweekly gross primary productivity by a factor of 1.5–2.3 at three tropical forest sites in Brazil, bringing it closer to estimates from eddy covariance measurements and remote sensing. Soil drought conditions are attenuated due to 8–30% lower water consumption during wet periods in presence of phosphorus limitation. When soils are dry, plant phosphorus acquisition is impaired by reduced ion mobility, despite an increase in net phosphorus mineralization. We conclude that water-phosphorus interactions cannot be omitted in analysis of the resilience of tropical ecosystems to precipitation changes.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2015

Study of quasielastic scattering using charged-current ν μ -iron interactions in the MINOS near detector

Kinematic distributions from an inclusive sample of 1.41×10 6 charged-current ν μ interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are also used to guide the selection of a subsample enriched in quasielastic ν μ Fe interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < E ν < 8 GeV, with < E ν > = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q 2 show the Monte Carlo model to be inadequate at low Q 2 . Its shortcomings are remedied via inclusion of a Q 2 -dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q 2 distribution for the quasielastic-enriched sample is carried out with the axial-vector mass M A of the dipole axial-vector form factor of the neutron as a free parameter. Furthermore, the effective M A which best describes the data is 1.23 +0.13 -0.09 (fit) +0.12 -0.15 (syst) GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Particle production with rapidity correlations in proton-nucleus collisions

We illustrate how a generalization of the JIMWLK formalism which treats independently the direct and complex conjugate amplitudes can be used to describe semi-inclusive multiparticle production with rapidity correlations in pA collisions. The evolution equations that are obtained with this formalism are susceptible of numerical implementation as a Langevin process.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2025

Across the Scales of the Nucleus: Understanding Short Range Correlations from Medium Modification to Probe Independence

The atomic nucleus presents an intricate system due to the non-linear forces described by Quantum Chromodynamics (QCD) that govern its structure. The range of scales involved is remarkable; the most massive nuclei weigh approximately five orders of magnitude more than the quarks that compose them. The nucleus can be analyzed at various levels, from quarks to hadrons to the nucleus as a whole. Short-Range Correlations (SRCs) within the nucleus play a significant role that spans these diverse scales. At the most fundamental level, SRCs influence the interaction between nucleons. The nucleon-nucleon (NN) interaction, arising from QCD, is crucial in determining nuclear properties. SRCs serve as valuable probes for measuring this NN interaction, as the nucleons within SRCs become effectively decoupled from the rest of the nucleus. Multiple experimental techniques, including electron scattering, have been employed to investigate the NN interaction through SRCs. However, our first project demonstrates that inclusive measurements alone are inadequate to constrain this interaction fully. Moving to the scale of the nucleus, SRCs contribute to the high-momentum tail of the nuclear spectral function. While the low-momentum region is characterized by nucleons exhibiting bulk properties, nucleons begin to pair into SRCs at higher momenta. Our research aims to bridge the understanding between the mean-field portion of the nucleus and its high-momentum SRC components. Additionally, SRCs affect the quark structure of protons, as evidenced by the EMC effect, which indicates that quarks behave differently when protons are embedded within a nucleus—an effect referred to as medium modification. This thesis explores the correlation between SRCs and medium modification across various experimental setups. Finally, we seek to establish an interpretation of the nuclear ground state. Accomplishing this requires demonstrating that our SRC observables are independent of the probe’s scale and scheme. The concluding project of this thesis illustrates how we utilize triple coincidence quasi-elastic scattering across a range of (Q2) values to develop a model-dependent framework for understanding SRC distributions within the nucleus’s ground-state wavefunction.

Denniston, A. W. Denniston [University of Tel Aviv↗

DOE OSTI2013

Multiscale Modeling of Inclusions and Precipitation Hardening in Metal Matrix Composites: Application to Advanced High-Strength Steels

In this study, the strengthening effect of inclusions and precipitates in metals is investigated within a multiscale approach that utilizes models at various length scales, namely, Molecular Mechanics (MM), discrete Dislocation Dynamics (DD), and an Eigenstrain Inclusion Method (EIM). Particularly, precipitates are modeled as hardsoft particles whose stress fields interact with dislocations. The stress field resulting from the elastic mismatch between the particles and the matrix is accounted for through the EIM. While the MM method is employed for the purpose of developing rules for DD for short range interaction between a single dislocation and an inclusion, the DD method is used to predict the strength of the composite resulting from the interaction between ensembles of dislocations and particles. As an application to this method, the mechanical behavior of Advanced High Strength Steel (AHSS) is investigated and the results are then compared to the experimental data. The results show that the finely dispersive precipitates can strengthen the material by pinning the dislocations up to a certain shear stress and retarding the recovery, as well as annihilation of dislocations. The DD results show that strengthening due to nano sized particles is a function of the density and size of the precipitates. This size effect is then explained using a mechanistic model developed based on dislocation-particle interaction.

Environmental Molecular Sciences Laboratory↗

DOE OSTI2017

Rapid communication: $K_{S}^{0}$ Production from beryllium target using 120 $\hbox {GeV}/\hbox {c}$ protons beam interactions at the MIPP experiment

We have measured the cross-section for the $K_{S}^{0}$ production from beryllium target using 120 $\hbox {GeV}/\hbox {c}$ protons beam interactions at the main injector particle production (MIPP) experiment at Fermilab. The data were collected with target having a thickness of 0.94% of the nuclear interaction length. The $K_{S}^{0}$ inclusive differential cross-section in bins of momenta is presented covering momentum range from $0.4\,\hbox {GeV}/\hbox {c}$ to $30\,\hbox {GeV}/\hbox {c}$ . The measured inclusive $K_{S}^{0}$ production cross-section amounts to $39.54\pm 1.46\delta _{\mathrm {stat}}\pm 6.97\delta _{\mathrm {syst}}$ mb and the value is compared with the prediction of FLUKA hadron production model.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2015

Muon neutrino charged current inclusive charged pion (CCπ{sup ±}) production in MINERνA

The production of charged pions by neutrinos interacting on nuclei is of great interest in nuclear physics and neutrino oscillation experiments. The MINERνA experiment is working towards releasing the world’s first high statistics neutrino pion production measurements in a few-GeV neutrino beam. We describe MINERνA’s CCπ{sup ±} analysis event selection in both the neutrino and antineutrino beams, noting reconstruction resolutions and kinematic limits. We also show area-normalized data-simulation comparisons of the reconstructed muon and charged pion kinetic energy distributions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2021

Gaseous cyclodextrin- closo -dodecaborate complexes χCD·B 12 X 12 2– (χ = α, β, and γ; X = F, Cl, Br, and I): electronic structures and intramolecular interactions

A fundamental understanding of cyclodextrin- closo -dodecaborate inclusion complexes is of great interest in supramolecular chemistry. Herein, we report a systematic investigation on the electronic structures and intramolecular interactions of perhalogenated closo -dodecaborate dianions B 12 X 12 2– (X = F, Cl, Br and I) binding to α-, β-, and γ-cyclodextrins (CDs) in the gas phase using combined negative ion photoelectron spectroscopy (NIPES) and density functional theory (DFT) calculations. The vertical detachment energy (VDE) of each complex and electronic stabilization of each dianion due to the CD binding (ΔVDE, relative to the corresponding isolated B 12 X 12 2– ) are determined from the experiments along α-, β- and γ-CD in the form of VDE (ΔVDE): 4.00 (2.10), 4.33 (2.43), and 4.30 (2.40) eV in X = F; 4.09 (1.14), 4.64 (1.69), and 4.69 (1.74) eV in X = Cl; 4.11 (0.91), 4.58 (1.38), and 4.70 (1.50) eV in X = Br; and 3.54 (0.74), 3.88 (1.08), and 4.05 (1.25) eV in X = I, respectively. All complexes have significantly higher VDEs than the corresponding isolated dodecaborate dianions with ΔVDE spanning from 0.74 eV at (α, I) to 2.43 eV at (β, F), sensitive to both host CD size and guest substituent X. DFT-optimized complex structures indicate that all B 12 X 12 2– prefer binding to the wide openings of CDs with the insertion depth and binding motif strongly dependent on the CD size and halogen X. Dodecaborate anions with heavy halogens, i.e. , X = Cl, Br, and I, are found outside of α-CD, while B 12 F 12 2– is completely wrapped by γ-CD. Partial embedment of B 12 X 12 2– into CDs is observed for the other complexes via multipronged B–X … H–O/C interlocking patterns. The simulated spectra based on the density of states agree well with those of the experiments and the calculated VDEs well reproduce the experimental trends. Molecular orbital analyses suggest that the spectral features at low binding energies originated from electrons detached from the dodecaborate dianion, while those at higher binding energies are derived from electron detachment from CDs. Energy decomposition analyses reveal that the electrostatic interaction plays a dominating role in contributing to the host–guest interactions for the X = F series partially due to the formation of a O/C–H … X–B hydrogen bonding network, and the dispersion forces gradually become important with the increase of halogen size.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2015

Charged current inclusive measurements in MINERνA

MINERvA is a neutrino scattering experiment stationed in the high intensity NuMI beam line at Fermilab, designed to measure neutrino cross sections, final states and nuclear effects on a variety of targets in the few-GeV region to reduce systematic uncertainties in oscillation experiments and provide new understanding of the nucleus. Here we present the current MINERvA results for inclusive charged current neutrino and anti-neutrino scattering in the active region of the detector and different neutrino cross section ratios with different nuclear targets.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2017

ChIMES: A Force Matched Potential with Explicit Three-Body Interactions for Molten Carbon

We present a new force field and development scheme for atomistic simulations of materials under extreme conditions. These models, which explicitly include twoand three-body interactions, are generated by fitting linear combinations of Chebyshev polynomials through force matching to trajectories from Kohn–Sham density functional theory (DFT).We apply our method to liquid carbon near the diamond/graphite/liquid triple point and at higher densities and temperatures, where metallization and manybody effects may be substantial. We show that explicit inclusion of three-body interaction terms allows our model to yield improved descriptions of both dynamic and structural properties over previous empirical potential efforts, while exhibiting transferability to nearby state points. The simplicity of our functional form and subsequent efficiency of parameter determination allows for extension of DFT to experimental time and length scales while retaining most of its accuracy.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2019

Status of the Inclusive Electron Neutrino Charged-Current Cross-Section Measurement in the NOvA Near Detector

aThe NOvA (NuMI Off-axis $\nu_{e}$ Appearance) experiment is a two-detector, long-baseline neutrino oscillation experiment hosted by Fermilab. The primary goal is to measure neutrino oscillation parameters associated with $\nu_\mu \rightarrow \nu_{\mu}$ disappearance and $\nu_\mu \rightarrow \nu_{e} $appearance over a distance of 810 km. These measurements require correct modeling of final state particle kinematics from charged-current (CC) neutrino interactions, thus the $\nu_{e}$ CC inclusive cross section is of particular importance to the appearance measurement. The high rate of neutrino interactions in the NOvA near detector located at Fermilab presents an excellent opportunity for neutrino-nucleus cross section measurements. We present the motivations, analysis techniques and current status of $\nu_{e}$ CC inclusive double-differential cross-section measurement using neutrino interactions recorded in the NOvA near detector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Examining the justification for the introduction of a fermion localization function

Becke and Edgecombe suggested in 1990 a theoretical tool to describe electron localization in atoms and molecules, an idea which was borrowed by a large number of nuclear theorists since 2011 to describe nucleon localization in nuclear systems. I argue here that these arguments are highly questionable and cannot be used in interacting systems where effects beyond the naive mean field or the simple Hartree-Fock framework are important and the inclusion of correlations induced by particle interactions is necessary in order to introduce such a localization function. Furthermore, I also describe several aspects of the exchange and irreducible two-body density matrices, which depend on the character and strength of the two-particle interaction and which can be useful in justifying the derivation of an appropriate energy density functional.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS1978

Superdense neutron matter

A relativistic theory of high-density matter is presented which takes into account the short-range interaction due to the exchange of spin-2 mesons. An equation of state is derived and used to compute neutron-star properties. The prediction of the theory for the values of maximum mass and moment of inertia for a stable neutron star are 1.75 solar masses and 1.68 by 10 to the 45th power g-sq cm, in very good agreement with the presently known observational bounds. The corresponding radius is found to be 10.7 km. It is found that the inclusion of the spin-2 interaction reduces the disagreement between the relativistic and nonrelativistic theories in their predictions of masses and moments of inertia.

Canuto, V.↗

DOE OSTI2012

The combined measurements of NC and CC DIS cross-sections at HERA

A combination is presented of the inclusive cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current deep-inelastic ep scattering at HERA. The combination uses data from unpolarized ep scattering taken during the HERA-I phase as well as measurements with longitudinally polarized electron or positron beams from the HERAII running period. The combination method takes the correlations of systematic uncertainties into account. The inclusion of the large HERA-II data set leads to an improved uncertainty especially at large four momentum transfer squared Q{sup 2}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗