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DOE OSTI2025

Quadrupole forces between quark and gluon subsystems inside higher-spin particles

We generalize the mechanical interpretation of the forces between quark and gluon subsystems, previously studied for the nucleon, to arbitrary higher-spin particles. For spin-0 and spin-1/2 particles, this force is characterized by the nonconserved $\overline{𝑐}$⁡(𝑡) form factor. However, such an interpretation has not yet been established for higher-spin particles due to the intricate structure of the nonconserved energy-momentum tensor (EMT) form factors. By performing a multipole expansion, we identify the physically meaningful combinations of the nonconserved covariant EMT form factors and provide them with a clear mechanical interpretation.

Baryons↗

NASA NTRS1988

The ijk forms of factorization methods. II - Parallel systems

The paper considers the 'ijk forms' of LU and Cholesky factorization on certain parallel computers. This extends an earlier analysis for vector computers. Attention is restricted to local memory systems with processors that may or may not have vector capability. Special attention is given to bus architectures but qualitative analyses are given for other interconnection systems.

Ortega, J. M.↗

NASA NTRS2013

SpaceCube Version 1.5

SpaceCube 1.5 is a high-performance and low-power system in a compact form factor. It is a hybrid processing system consisting of CPU (central processing unit), FPGA (field-programmable gate array), and DSP (digital signal processor) processing elements. The primary processing engine is the Virtex- 5 FX100T FPGA, which has two embedded processors. The SpaceCube 1.5 System was a bridge to the SpaceCube 2.0 and SpaceCube 2.0 Mini processing systems. The SpaceCube 1.5 system was the primary avionics in the successful SMART (Small Rocket/Spacecraft Technology) Sounding Rocket mission that was launched in the summer of 2011. For SMART and similar missions, an avionics processor is required that is reconfigurable, has high processing capability, has multi-gigabit interfaces, is low power, and comes in a rugged/compact form factor. The original SpaceCube 1.0 met a number of the criteria, but did not possess the multi-gigabit interfaces that were required and is a higher-cost system. The SpaceCube 1.5 was designed with those mission requirements in mind. The SpaceCube 1.5 features one Xilinx Virtex-5 FX100T FPGA and has excellent size, weight, and power characteristics [4×4×3 in. (approx. = 10×10×8 cm), 3 lb (approx. = 1.4 kg), and 5 to 15 W depending on the application]. The estimated computing power of the two PowerPC 440s in the Virtex-5 FPGA is 1100 DMIPS each. The SpaceCube 1.5 includes two Gigabit Ethernet (1 Gbps) interfaces as well as two SATA-I/II interfaces (1.5 to 3.0 Gbps) for recording to data drives. The SpaceCube 1.5 also features DDR2 SDRAM (double data rate synchronous dynamic random access memory); 4- Gbit Flash for storing application code for the CPU, FPGA, and DSP processing elements; and a Xilinx Platform Flash XL to store FPGA configuration files or application code. The system also incorporates a 12 bit analog to digital converter with the ability to read 32 discrete analog sensor inputs. The SpaceCube 1.5 design also has a built-in accelerometer. In addition, the system has 12 receive and transmit RS- 422 interfaces for legacy support. The SpaceCube 1.5 processor card represents the first NASA Goddard design in a compact form factor featuring the Xilinx Virtex- 5. The SpaceCube 1.5 incorporates backward compatibility with the Space- Cube 1.0 form factor and stackable architecture. It also makes use of low-cost commercial parts, but is designed for operation in harsh environments.

Geist, Alessandro↗

DOE OSTI2017

Phenomenology of $ {\Lambda}_b\to {\Lambda}_c\tau {\overline{\nu}}_{\tau } $ using lattice QCD calculations

In a recent paper we studied the effect of new-physics operators with different Lorentz structures on the semileptonic Λ b → Λ c τ ν ¯ τ decay. This decay is of interest in light of the R(D (*)) puzzle in the semileptonic B ¯ → D ( ∗ ) τ ν ¯ τ decays. In this work we add tensor operators to extend our previous results and consider both model-independent new physics (NP) and specific classes of models proposed to address the R(D (*)) puzzle. We show that a measurement of R ( Λ c ) = B [ Λ b → Λ c τ ν ¯ τ ] / B [ Λ b → Λ c ℓ ν ¯ ℓ ] can strongly constrain the NP parameters of models discussed for the R(D (*)) puzzle. We use form factors from lattice QCD to calculate all Λ b → Λ c τ ν ¯ τ observables. The Λ b → Λ c tensor form factors had not previously been determined in lattice QCD, and we present new lattice results for these form factors here.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2017

Analysis of $D$ + → $K¯$ 0 $e$ + $ν$ $e$ and $D$ + → $π$ 0 $e$ + $ν$ $e$ semileptonic decays

Using 2.93 fb –1 of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays D + → K¯ 0 e + ν e and D + → π 0 e + ν e . Here, we measure the absolute decay branching fractions B(D + → K¯ 0 e + ν e ) = (8.60 ± 0.06 ± 0.15) × 10 –2 and B(D + → π 0 e + ν e ) = (3.63 ± 0.08 ± 0.05) × 10 –3 , where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of |V cs | and |V cd | from Particle Data Group fits assuming CKM unitarity, we obtain the values of the form factors at q 2 = 0, $f$ $^{K}_{+}$(0) = 0.725 ± 0.004 ± 0.012 and $f$ $^{π}_{+}$(0) = 0.622 ± 0.012 ± 0.003. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements |V cs | = 0.944 ± 0.005 ± 0.015 ± 0.024 and |V cd | = 0.210 ± 0.004 ± 0.001 ± 0.009, where the third uncertainties are theoretical.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS2012

SpaceCube Mini

This version of the SpaceCube will be a full-fledged, onboard space processing system capable of 2500+ MIPS, and featuring a number of plug-andplay gigabit and standard interfaces, all in a condensed 3x3x3 form factor [less than 10 watts and less than 3 lb (approximately equal to 1.4 kg)]. The main processing engine is the Xilinx SIRF radiation- hardened-by-design Virtex-5 FX-130T field-programmable gate array (FPGA). Even as the SpaceCube 2.0 version (currently under test) is being targeted as the platform of choice for a number of the upcoming Earth Science Decadal Survey missions, GSFC has been contacted by customers who wish to see a system that incorporates key features of the version 2.0 architecture in an even smaller form factor. In order to fulfill that need, the SpaceCube Mini is being designed, and will be a very compact and low-power system. A similar flight system with this combination of small size, low power, low cost, adaptability, and extremely high processing power does not otherwise exist, and the SpaceCube Mini will be of tremendous benefit to GSFC and its partners. The SpaceCube Mini will utilize space-grade components. The primary processing engine of the Mini is the Xilinx Virtex-5 SIRF FX-130T radiation-hardened-by-design FPGA for critical flight applications in high-radiation environments. The Mini can also be equipped with a commercial Xilinx Virtex-5 FPGA with integrated PowerPCs for a low-cost, high-power computing platform for use in the relatively radiation- benign LEOs (low-Earth orbits). In either case, this version of the Space-Cube will weigh less than 3 pounds (.1.4 kg), conform to the CubeSat form-factor (10x10x10 cm), and will be low power (less than 10 watts for typical applications). The SpaceCube Mini will have a radiation-hardened Aeroflex FPGA for configuring and scrubbing the Xilinx FPGA by utilizing the onboard FLASH memory to store the configuration files. The FLASH memory will also be used for storing algorithm and application code for the PowerPCs and the Xilinx FPGA. In addition, it will feature highspeed DDR SDRAM (double data rate synchronous dynamic random-access memory) to store the instructions and data of active applications. This version will also feature SATA-II and Gigabit Ethernet interfaces. Furthermore, there will also be general-purpose, multi-gigabit interfaces. In addition, the system will have dozens of transceivers that can support LVDS (low-voltage differential signaling), RS-422, or SpaceWire. The SpaceCube Mini includes an I/O card that can be customized to meet the needs of each mission. This version of the SpaceCube will be designed so that multiple Minis can be networked together using SpaceWire, Ethernet, or even a custom protocol. Scalability can be provided by networking multiple SpaceCube Minis together. Rigid-Flex technology is being targeted for the construction of the SpaceCube Mini, which will make the extremely compact and low-weight design feasible. The SpaceCube Mini is designed to fit in the compact CubeSat form factor, thus allowing deployment in a new class of missions that the previous SpaceCube versions were not suited for. At the time of this reporting, engineering units should be available in the summer 2012.

Michael Lin↗

DOE OSTI2013

Porous media properties of reticulated shape memory polymer foams and mock embolic coils for aneurysm treatment

Background: Shape memory polymer (SMP) foams are being investigated as an alternative aneurysm treatment method to embolic coils. The goal of both techniques is the reduction of blood flow into the aneurysm and the subsequent formation of a stable thrombus, which prevents future aneurysm rupture. The purpose of this study is to experimentally determine the parameters, permeability and form factor, which are related to the flow resistance imposed by both media when subjected to a pressure gradient. Methods: The porous media properties—permeability and form factor—of SMP foams and mock embolic coils (MECs) were measured with a pressure gradient method by means of an in vitro closed flow loop. We implemented the Forchheimer-Hazen-Dupuit-Darcy equation to calculate these properties. Mechanically-reticulated SMP foams were fabricated with average cell sizes of 0.7E-3 and 1.1E-3 m, while the MECs were arranged with volumetric packing densities of 11-28%. Results: The permeability of the SMP foams was an order of magnitude lower than that of the MECs. The form factor differed by up to two orders of magnitude and was higher for the SMP foams in all cases. The maximum flow rate of all samples tested was within the inertial laminar flow regime, with Reynolds numbers ranging between 1 and 35. Conclusions: The SMP foams impose a greater resistance to fluid flow compared to MECs, which is a result of increased viscous and inertial losses. These results suggest that aneurysms treated with SMP foam will have flow conditions more favorable for blood stasis than those treated with embolic coils having packing densities ≤ 28%.

36 MATERIALS SCIENCE↗

DOE OSTI2016

Radiative decays of resonances on the lattice

We discuss a generalization of the Lüscher approach to the calculation of the matrix elements of the unstable states. A theoretical framework for the lattice extraction of the ΔNγ* transition form factors is formulated. The procedure to measure the form factors at the resonance pole is given. The current theoretical progress on the B → K*γ* decays is briefly summarized.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2015

MO-F-CAMPUS-I-03: Tissue Equivalent Material Phantom to Test and Optimize Coherent Scatter Imaging for Tumor Classification

Purpose: To accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Methods: A breast phantom has been designed to assess the capability of coded aperture coherent x-ray scatter imaging system to classify different types of breast tissue (adipose, fibroglandular, tumor). The tissue-equivalent phantom was modeled as a hollow plastic cylinder containing multiple cylindrical and spherical inserts that can be positioned, rearranged, or removed to model different breast geometries. Each enclosure can be filled with a tissue-equivalent material and excised human tumors. In this study, beef and lard, placed inside 2-mm diameter plastic Nalgene containers, were used as surrogates for fibroglandular and adipose tissue, respectively. The phantom was imaged at 125 kVp, 40 mA for 10 seconds each with a 1-mm pencil beam. The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor, or momentum transfer (q) spectrum of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: The tissue equivalent phantom was found to accurately model different types of breast tissue by qualitatively comparing our measured form factors to those of adipose and fibroglandular tissue from literature. Our imaging system has been able to define the location and composition of the various materials in the phantom. Conclusion: This work introduces a new tissue equivalent phantom for testing and optimization of our coherent scatter imaging system for material classification. In future studies, the phantom will enable the use of a variety of materials including excised human tissue specimens in evaluating and optimizing our imaging system using pencil- and fan-beam geometries. United States Department of Homeland Security Duke University Medical Center - Department of Radiology Carl E Ravin Advanced Imaging Laboratories Duke University Medical Physics Graduate Program.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

Separated response functions in exclusive, forward π ± electroproduction on deuterium

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q 2 , and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π⁻ and π⁺ electroproduction are particularly informative. Ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central Q 2 values of 0.6, 1.0, 1.6 GeV 2 at W=1.95 GeV, and Q 2 =2.45 GeV 2 at W=2.22 GeV. There was significant coverage in Φ And ϵ, which allowed separation of σ L,T,LT,TT . Results: σL shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, σ T is much flatter versus t. The longitudinal/transverse ratios evolve with Q 2 and t, and at the highest Q 2 =2.45 GeV 2 show a slight enhancement for π⁻ Production compared to π⁺. The π⁻/π⁺+ ratio for transverse photons exhibits only a small Q 2 -dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The σ TT /σ T ratio also drops rapidly with Q 2 , qualitatively consistent with s-channel helicity conservation. The π⁻/π⁺ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2019

Colloquium: Roper resonance: Toward a solution to the fifty year puzzle

Discovered in 1963, the Roper resonance appears to be an exact copy of the proton except that its mass is 50% greater and it is unstable. These features of the Roper have been very difficult to explain so that for half a century this lightest excited state of the proton has defied understanding. The last decade has presented a new challenge, viz. precise information on the proton-to-Roper electroproduction transition form factors. Reaching to momentum transfer Q 2 ≈ 4.5 GeV 2 , the data probe a domain within which hard valence-quark degrees of freedom could be expected to determine form factor behavior. An explanation of the Roper should combine an understanding of all these things. This is a prodigious task, but a ten-year international collaborative effort, involving experimentalists and theorists, has presented a candidate solution to the puzzle. Namely, the observed Roper is at the heart of the proton’s first radial excitation, consisting of a dressed-quark core augmented by a meson cloud that reduces the core mass by approximately 20% and materially alters its electroproduction form factors on Q 2 < 2 m N 2 , where m N is the proton’s mass. This Colloquium describes the experimental developments which enabled electroproduction data to be procured within a domain that is the purview of strong quantum chromodynamics, thereby providing challenges and opportunities for modern theory, and surveys the developments in reaction models and QCD theory that have enabled this picture of the Roper resonance to be drawn.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

Bootstrapping 2d ϕ 4 theory with Hamiltonian truncation data

We combine the methods of Hamiltonian Truncation and the recently proposed generalisation of the S-matrix bootstrap that includes local operators to determine the two-particle scattering amplitude and the two-particle form factor of the stress tensor at s > 0 in the 2d Φ 4 theory. We use the form factor of the stress tensor at s ≤ 0 and its spectral density computed using Lightcone Conformal Truncation (LCT), and inject them into the generalized S-matrix bootstrap set-up. The obtained results for the scattering amplitude and the form factor are fully reliable only in the elastic regime. We independently construct the “pure” S-matrix bootstrap bounds (bootstrap without including matrix elements of local operators), and find that the sinh-Gordon model and its analytic continuation the “staircase model” saturate these bounds. Surprisingly, the Φ 4 two-particle scattering amplitude also very nearly saturates these bounds, and moreover is extremely close to that of the sinh-Gordon/staircase model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Neutral-current neutrino scattering from the deuteron

Neutral-current neutrino scattering from the deuteron leading to proton-neutron final states is considered using an approach that incorporates relativistic dynamics and consequently provides robust modeling at relatively high energies and momenta. In this work the focus is placed on the fully exclusive reaction where both the proton and neutron in the final state are assumed to be detected. Accordingly, the incident neutrino energy, the neutrino scattering angle and the scattered neutrino's energy can all be reconstructed. It is shown that for specific choices of kinematics the reaction proceeds mainly via scattering from the proton, while for other choices of kinematics it proceeds mainly from the neutron. Specific asymmetries are introduced to focus on these attributes. Measurements in both regions have the potential to yield valuable information on the nucleon's electroweak form factors at momentum transfers up to a (GeV/c)$^2$. In particular, the cross sections are shown to be very sensitive to the isoscalar axial-vector form factor, and sensitive but less so to the magnetic strangeness form factor. Comparisons with other reactions, specifically charge-changing neutrino reactions and both parity-conserving and -violating electron scattering, have the potential to provide new ways to test the Standard Model.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2025

Appraising constrained second-order power corrections in HQET with Λ b →Λ c Ι⁢ν

We derive the Λ b →Λ c form factors for the Standard Model and beyond at second order in heavy quark effective theory, applying the recently proposed residual chiral expansion to reduce the set of unknown subsubleading hadronic functions to a single, highly constrained function, that is fully determined by hadron mass parameters at zero recoil. We fit a form factor parametrization based on these results to all available lattice QCD predictions and experimental data. We find that the constrained and predictive structure of the form factors under the residual chiral expansion is in excellent agreement with lattice QCD predictions and experimental data, as well as prior heavy-quark-effective-theory-based fits.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

New opportunities for Insight into Emergence of Hadron Mass from Studies of Nucleon Resonance Electroexcitation

Understanding the emergence of hadron mass (EHM) represents one of the most challenging and still open problems in the Standard Model. Results of EHM studies from the nucleon resonance electroexcitation amplitudes (gvpN* electrocouplings) determined from exclusive meson electroproduction data measured with the CLAS detector will be presented in this talk. These CLAS data have provided the first and only available results on the evolution of the ?vpN* electrocouplings with photon virtuality Q2 up to 5 GeV2 for most nucleon resonances in the mass range up to 1.8 GeV. A successful description of the CLAS results on the Q2-evolution of the ?(1232)3/2+, N(1440)1/2+, and ?(1600)3/2+ electrocouplings achieved within the CSM approach by employing the same dressed quark mass function inferred from the QCD Lagrangian, which also provided a successful description of the pion elastic electromagnetic form factor and PDF, and nucleon elastic form factor, conclusively demonstrated the capability of gaining insight into EHM. The expected results from the CLAS12 detector on the Q2-evolution of the gvpN* electrocouplings for all prominent resonances in the mass range up to 2 GeV at the still almost unexplored range of Q2>5 GeV2 will allow us to place tight constraints on the dressed quark mass function in the range of quark momenta where the substantial part of hadron mass ~50% is expected to be generated. Consistent results on the momentum dependence of the dressed quark mass obtained from analyses of the ?vpN* electrocouplings of nucleon resonances of different structure will validate insight into EHM in a nearly model-independent way, allowing us to address key open problems in hadron physics on the emergence of hadron mass and nucleon resonance structure from QCD.

Mokeev, Viktor↗

DOE OSTI2017

Exploring Hadron Structure Through Exclusive Kaon Electroproduction

The kaon electroproduction cross section was extracted from data from the E93-018 and the E01-004 (FPI-2) experiments taken at the Thomas Jefferson National Accelerator Facility in the p(e,e'K + )Λ channel. The cross section was fully separated into longitudinal, transverse, and two interference components at four-momentum transfers Q 2 of 1.0 (GeV/c) 2 (with center of mass energy W=1.81 GeV), 1.36 and 2.07 (GeV/c) 2 (W=2.31 GeV). The kaon form factor (FK) was extracted from the longitudinal cross section in these kinematics using the Regge model by Vanderhaeghen, Guidal, and Laget. Results show F K to be systematically lower than the empirical monopole form, although still compatible with this form within the estimated uncertainties. The resulting kaon form factor values were combined with the world pion and kaon form factor data to extract the transverse change densities of the pion and kaon. These were compared to that of the proton, showing a possible experimental glimpse of the transition between the proton core and the meson cloud in terms of transverse densities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2018

Quark Mass Functions and Pion Structure in the Covariant Spectator Theory

The Covariant Spectator Theory is applied to the description of quarks and the pion. The dressed quark mass function is calculated dynamically in Minkowski space and used in the calculation of the pion electromagnetic form factor. The effects of the mass function on the pion form factor and the different quark-pole contributions to the triangle diagram then are analyzed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2014

Chiral dynamics and peripheral transverse densities

In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗