Erratum: Search with EGRET for a gamma ray line from the galactic center [Phys. Rev. D 76, 063006 (2007)]
No abstract prepared.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Results for “INTERACTION RANGE”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Exploring the Strong Interaction of Three-Body Systems at the LHC
Deuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments, and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work, K + -d and p-d femtoscopic correlations measured by the ALICE Collaboration in proton-proton (pp) collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K + -d correlation shows that the relative distances at which deuterons and protons or kaons are produced are around 2 fm. The analysis of the p-d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body system in the strange and charm sectors.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
η′ meson photoproduction off nucleon in the isobar model
The recent high-precision data for the reaction γ p → pη′ at center-of-mass energies from near threshold up to 2.84 GeV is obtained by the CLAS collaboration at the Jefferson Laboratory [1] have been analyzed within an isobar model. The η′ photoproduction can be described quite well over the entire energy range of available data by considering S {sub 11} and P{sub 11} resonances, in addition to the nucleon s- and u-channel resonance contribution, also t-channel mesonic currents. For the resonances considered, our analysis we use masses and widths advocated by the Particle Data Group. We emphasize, that cross-section data alone are able to reproduce the value of resonance parameters and hadronic coupling constant.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
New anti-neutrino cross-section results from MiniBooNE
The first measurements of antineutrino charged-current quasielastic (ν{sup ¯}{sub μ} CCQE, ν{sub µ} + N → µ{sup +} + N{sup ′}) and neutral-current elastic (ν{sup ¯}{sub μ} NCE, ν{sub µ} + N → ν{sub µ} + N) cross sections with 〈E{sub ν{sup ¯}}〉<1 GeV are presented. To maximize the precision of these measurements, many data-driven background measurements were executed, including a first demonstration of charge separation using a non-magnetized detector. Apart from extending our knowledge of antineutrino interactions by probing a new energy range, these measurements constrain signal and background processes for current and future neutrino oscillation experiments and also carry implications for intra-nuclear interactions.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Spectral and Structural Characteristics for Cluster Systems of Charged Brownian Particles
We report on the results of analytic and numerical investigations of the dynamics for bounded ensembles of charged Brownian particles in the potential field of an electrostatic trap. Simulation has been performed for cluster systems consisting of (approximately up to one thousand) particles with the Coulomb interaction in a wide range of their parameters. The spectral structures and structural characteristics of the systems being simulated have been compared. The dependence of the form of the pair correlation function and the size of cluster systems on the temperature and the number of particles has been analyzed. The relation between the spectral density of displacements of the center of mass and of individual particles and the structural characteristics and nonideality parameter of the ensembles being modeled has been investigated.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Incorporating Brueckner-Hartree-Fock correlations in energy density functionals
Recently, a microscopically motivated nuclear energy density functional was derived by applying the density-matrix expansion to the Hartree-Fock (HF) energy obtained from long-range chiral effective-field theory two- and three-nucleon interactions. However, the HF approach cannot account for all many-body correlations. One class of correlations is included by Brueckner-Hartree-Fock (BHF) theory, which gives an improved definition of the one-body HF potential by replacing the interaction by a reaction matrix G. In this paper, we find that the difference between the G matrix and the similarity renormalization group evolved nucleon-nucleon potential V SRG can be well accounted for by a truncated series of contact terms. This is consistent with renormalization-group decoupling generating a series of counterterms as short-distance physics is integrated out. Here, the coefficients C n of the power series expansion Σ C n q n for the counterterms are examined for two potentials at different renormalization-group resolutions and at a range of densities. The success of this expansion for G–V SRG means we can apply the density-matrix expansion at the HF level with low-momentum interactions and density-dependent zero-range interactions to model BHF correlations.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Development and refinement of an in situ ‘molecular microscope’ utilizing ultrahigh resolution mass spectrometry
The ability to elucidate complex metabolic behavior of living organisms in situ and with cellular resolution is a bioanalytical grand challenge that is yet to be realized. Mass spectrometry imaging (MSI) using laser ablation electrospray ionization mass spectrometry (LAESI) has recently been demonstrated, and holds promise for direct spatially resolved molecular profiling in a variety of living systems of DOE relevance (e.g., plant leaf, stem, and root tissue). The LAESI MSI approach has revealed cell-to-cell heterogeneity of metabolites within living plant tissue, in a multiplexed fashion and without the need for labeling. Cellular resolution by in situ, ambient pressure MSI methods are far from routine, however, and have inadequate spatial resolution for many biological questions of interest. We propose to develop next-generation LAESI approaches, using advanced fiber optics and transmission-based geometries, in efforts to attain dynamic bioanalysis of living systems at better than 20 µm lateral resolution. In parallel with LAESI innovations, attendant increases in sensitivity and dynamic range of the mass spectrometer system will also be necessary for detection of the limited amount of material being ionized. To respond to this need, a new, high magnetic field (21 Tesla) Fourier Transform Ion Cyclotron Resonance (FTICR) MS at the EMSL/PNNL will be coupled with the newly developed LAESI source. This mass spectrometer, currently being assembled, will be one of only two such systems in the world, and the only one in a DOE laboratory or user facility. Fundamentally, all key figures of merits of FTICR MS performance improve with increased magnetic field strength, providing the ability to achieve unparalleled molecular specificity (near unequivocal molecular constituent identification) at the highest possible mass resolving power and sensitivity. The work proposed here will greatly increase the utility of this FTICR MS instrument, providing unique capabilities to support BER-relevant science. The research plan is comprised of three tasks, two of which are directed by the academic leads (University of Missouri and George Washington University), and one of which will be performed in conjunction with the BER user facility at EMSL/PNNL. In task 1, advancements of the LAESI technology will be achieved, with oversight and leadership of Professor Akos Vertes of George Washington University. In task 2, incorporation of this ion source with EMSL’s new 21T FTICR MS system will be undertaken, supplemented by global omics measurements and calibrated against more conventional MSI platforms also available at EMSL (Drs. Pasa-Tolic, Anderton, and Koppenaal team). In the final task, the resultant innovations and advancements will be tested and validated by addressing important BER relevant science questions on model systems of interest under the direction of Professor Gary Stacey of the University of Missouri. This research follows on key recommendations of the recent BER “Research in Sustainable Bioenergy” report that, for example, stressed that “The design of sustainable biofuel systems requires knowledge about key plant-microbe-environment interactions that provide a range of ecosystem services.” This task will focus on validation of the instrumentation developed through this proposal, advertising this capability to the community through demonstration and, finally, discovering new biology relevant to the BER mission. This final objective will make use of Setaria viridis, a model C4 grass species, as well as switchgrass and sorghum, two promising biofuel crops. Specifically, we will demonstrate applicability to plant-microbe rhizosphere interactions focusing on the biological nitrogen fixation by monitoring metabolic changes in real-time with nutrient, growth condition, and other perturbations.
09 BIOMASS FUELS↗
Role of electrons in collision cascades in solids. I. Dissipative model
In this article, we present a detailed model for the nonadiabatic coupling between ions and electrons in energetic ion-solid interactions over a wide range of energies in concentrated solid-solution fcc alloys of the 3d transition metals Ni, Co, Fe, and Cr. The model is based on general statistical mechanical principles and results in a stochastic modification of the classical nuclei motion which is parameterized by the first-principles calculation of a dissipation function produced by explicit time-dependent electronic evolution. This model provides a full picture of an entire collision process, from the ballistic to the thermal phases of a cascade, giving a detailed description of the energy exchange between ions and electrons till their final thermalization, removing in this way some ad hoc assumptions used in the state-of-the-art atomistic two-temperature models. Here, this work is separated in two papers; in the present Part I, we report on the ab initio methodology used to translate stopping power and electron-phonon interaction into a parameterized dissipation function; Part II, to be published, addresses the nonadiabatic ion dynamics using our modified Langevin dynamics [Tamm et al. Phys. Rev. Lett. 120, 185501 (2018)] applying the dissipation functions developed here to specific collision cascade events.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Finite-range effects in dilute Fermi gases at unitarity
We develop a theoretical method going beyond the contact-interaction approximation frequently used in mean-field theories of many-fermion systems, based on the low-energy T matrix of the pair potential to rigorously define the effective radius of the interaction. One of the main consequences of our approach is the possibility to investigate finite-density effects, which are outside the range of validity of approximations based on {delta}-like potentials. We apply our method to the calculation of density-dependent properties of an ultracold gas of {sup 6}Li atoms at unitarity, whose two-body interaction potential is calculated using ab initio quantum chemistry methods. We find that density effects will be significant in ultracold gases with densities 1 order of magnitude higher than those attained in current experiments.
74 ATOMIC AND MOLECULAR PHYSICS↗
Impact of Monomer Sequence, Composition and Chemical Heterogeneity on Copolymer-Mediated Effective Interactions between Nanoparticles in Melts
The microscopic polymer reference interaction site model theory is applied to study the structural correlations of dilute spherical nanoparticles dissolved in AB copolymer melts of variable architecture (alternating, random), composition, and monomernanoparticle adsorption strengths that span the depletion, steric stabilization, and bridging regimes. Comparison of the calculations of the monomerparticle pair correlations and polymer-mediated nanoparticle potential of mean force (PMF) with the behavior of reference homopolymers and a binary AB blend are also performed. All intermonomer potentials are hard core, which precludes polymer macrophase or microphase separation, thereby allowing the consequences of differential monomer wettability on nanoparticle spatial organization to be isolated. For each copolymer case, one monomer species adsorbs more strongly on the filler than the other, mimicking a specific attraction. The PMF for the alternating copolymer is similar to that of an analogous homopolymer with additional spatial modulation or layering features. Random copolymers, and the polymer blend, mediate a novel strong and spatially long-range attractive bridging type interaction between nanoparticles at moderate to high adsorption strengths. The depth of this attraction in the PMF is a nonmonotonic function of random copolymer composition, reflecting subtle competing enthalpic and entropic considerations. Virial-based estimates of the maximum solubility of nanoparticles are computed.
Hall, Lisa M.↗
Massive photons: An infrared regularization scheme for lattice QCD + QED
The commonly adopted approach for including electromagnetic interactions in lattice QCD simulations relies on using finite volume as the infrared regularization for QED. The long-range nature of the electromagnetic interaction, however, implies that physical quantities are susceptible to power-law finite volume corrections, which must be removed by performing costly simulations at multiple lattice volumes, followed by an extrapolation to the infinite volume limit. In this work, we introduce a photon mass as an alternative means for gaining control over infrared effects associated with electromagnetic interactions. We present findings for hadron mass shifts due to electromagnetic interactions (i.e., for the proton, neutron, charged and neutral kaon) and corresponding mass splittings, and compare the results with those obtained from conventional QCD+QED calculations. Results are reported for numerical studies of three flavor electroquenched QCD using ensembles corresponding to 800 MeV pions, ensuring that the only appreciable volume corrections arise from QED effects. The calculations are performed with three lattice volumes with spatial extents ranging from 3.4 - 6.7 fm. As a result, we find that for equal computing time (not including the generation of the lattice configurations), the electromagnetic mass shifts can be extracted from computations on a single (our smallest) lattice volume with comparable or better precision than the conventional approach.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Study of background processes with the formation of neutrons in nuclear reactions in the energy range of 26–32 kev
The nature of background processes accompanying astrophysical nuclear reactions induced by hydrogen, helium, and neon ions in deuterated targets with small cross sections has been studied in calculations and experiments. The experiments have been performed at a Hall pulsed plasma accelerator in the ion energy range of 26–32 keV. The yield of background neutrons and γ-quanta with energies below 4 MeV in the proton-induced D(p, γ){sup 3}He reaction is primarily due to the presence of a natural impurity of gaseous deuterium in gaseous hydrogen and the chain of D(D, {sup 3}He)n → (n, γ) or (n, n'γ) reactions. A small contribution comes from the chain of D({sup 1}H, {sup 1}H)D → D(D, {sup 3}He)n → (n, γ) or (n, n'γ) reactions. It has been shown that background neutrons and γ-quanta from the D(4He, γ)6Li reaction are entirely due to the chain of D({sup 4}He, {sup 4}He)D → D(D, {sup 3}He)n → (n, γ) or (n, n'γ) reactions. It has been shown that the yield of neutrons and γ-ray photons detected at the interaction of neon ions with deuterated targets is also entirely due to the chain of elastic- scattering reactions of neon ions on deuterons in the target and to subsequent inelastic processes of interaction of deuterons accelerated at elastic scattering with other deuterons of the target. The main contribution to the yields of background neutrons and γ-quanta comes from doubly charged neon ions. The main conclusion is that the explanation of the yield of neutrons and γ-quanta at the interaction of hydrogen, helium, and neon ions with deuterated targets does not require “exotic” theoretical models.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Magnetic behavior of La-doped Fe{sub 3}O{sub 4} studied by perturbed angular correlation spectroscopy with {sup 111}Cd and {sup 140}Ce
In this paper, the local magnetic properties of La-doped Fe{sub 3}O{sub 4} (5% and 10%) bulk and Nanoparticles (NPs) samples were studied by measuring hyperfine interactions in a wide range of temperature from 10 to 900 K with perturbed γ-γ angular correlation spectroscopy using {sup 111}In({sup 111}Cd) and {sup 140}La({sup 140}Ce) as probe nuclei. Results for the temperature dependence of the magnetic hyperfine field (B{sub hf}) for bulk and NP samples, pure and doped with La show that its behavior follows a second order Brillouin-like transition from which the Curie temperature (T{sub C}) was determined (T{sub C} ∼ 855 K). Results also show two different regions in NP samples: the core where a minor fraction of probe nuclei with well defined magnetic dipole frequency was observed and the shell where a major fraction with broad distributed electric quadrupolar frequency (surface effect in NP) was observed. The Verwey transition T{sub V} ∼ 120 K, due the order disorder phase, was also observed in all samples. The results are discussed in terms of the magnetic exchange interaction between Fe{sup 2+} and Fe{sup 3+} ions in the two regions of NP.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
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↗
Negative-ion resonances in total cross sections for slow electron-sodium collisions
The interaction of electrons and atomic sodium was studied by using the momentum space coupled-channel optical method at low-impact energies. Total scattering cross sections have been calculated, and negative-ion resonances have been located. The present calculation results are in good agreement with available experimental data and previous theoretical results. We have obtained resonance features at 4.166 and 4.502 eV and also found possible resonance structures near the ionization threshold in the total cross sections.
74 ATOMIC AND MOLECULAR PHYSICS↗
LDRD23-0184: Resilience and Hazard Risk Assessment to Prioritize Security Operations for Decisions and Impacts (RHAPSODI)
Recent examples provide a significant concern for the resilience of the U.S. electric grid and represent a need for enhanced decision-making to address an increasingly wide range of complex system interactions and potential consequences. In response, this LDRD project produced a proof-of-concept evaluation called the Resilience and Hazard Assessment to Prioritize Security Operations for Decisions and Impacts (RHAPSODI) methodology as an agile and flexible analytic framework capable of addressing multiple, diverse threats to desired electric grid performance. After empirically grounding needs for the future of U.S. electric grid resilience, this project employed the systems-theoretic process analysis (STPA) to develop a systems engineering risk model. The results of a completed feasibility study of a notional high voltage transmission system demonstrate an improved ability to incorporate both spatial (e.g., geographically distributed) and temporal (e.g., dynamic and time-dependent) elements of security risk to the gird. The success of this LDRD project provides the foundation for further evolution of the systems engineering risk model for the grid; derivation of quantitative approaches to evaluate risk and resilience performance; facilitation of agile experimenting and grid sensitivity to a range of vulnerabilities; and development of tools to assist decision-makers in enhancing U.S. electrical grid resilience.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Many-body dissipative particle dynamics simulation of liquid/vapor and liquid/solid interactions
The combination of short-range repulsive and long-range attractive forces in Many-body Dissipative Particle Dynamics (MDPD) is examined at a vapor/liquid and liquid/solid interface. Based on the radial distribution of the virial pressure in a drop at equilibrium, a systematic study is carried out to characterize the sensitivity of the surface tension coefficient with respect to the inter-particle interaction parameters. For the first time, this study highlights the approximately cubic dependence of the surface tension coefficient on the bulk density of the fluid. In capillary flow, MDPD solutions are shown to satisfy the condition on the wavelength of an axial disturbance leading to the pinch-off of a cylindrical liquid thread. Correctly, no pinch-off occurs below the cutoff wavelength. MDPD is augmented by a set of bell-shaped weight functions to model interaction with a solid wall. There, hydrophilic and hydrophobic behaviors, including the occurrence of slip in the latter, are reproduced using a modification in the weight function that avoids particle clustering. Finally, the dynamics of droplets entering an inverted Y-shaped fracture junction is correctly captured in simulations parameterized by the Bond number, proving the flexibility of MDPD in modeling interface-dominated flows.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Communication: Accurate higher-order van der Waals coefficients between molecules from a model dynamic multipole polarizability
Due to the absence of the long-range van der Waals (vdW) interaction, conventional density functional theory (DFT) often fails in the description of molecular complexes and solids. In recent years, considerable progress has been made in the development of the vdW correction. However, the vdW correction based on the leading-order coefficient C{sub 6} alone can only achieve limited accuracy, while accurate modeling of higher-order coefficients remains a formidable task, due to the strong non-additivity effect. Here, we apply a model dynamic multipole polarizability within a modified single-frequency approximation to calculate C{sub 8} and C{sub 10} between small molecules. We find that the higher-order vdW coefficients from this model can achieve remarkable accuracy, with mean absolute relative deviations of 5% for C{sub 8} and 7% for C{sub 10}. Inclusion of accurate higher-order contributions in the vdW correction will effectively enhance the predictive power of DFT in condensed matter physics and quantum chemistry.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗