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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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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Measurement of the azimuthal anisotropy of charged particles in sNN=5.36TeV O16+O16 and Ne20+Ne20 collisions with the ATLAS detector

This paper presents the first measurements of the azimuthal anisotropy coefficients , which quantify the -order Fourier modulation of charged-particle azimuthal distributions, for in and collisions recorded with the ATLAS detector at the CERN Large Hadron Collider in 2025. The coefficients are measured as a function of transverse momentum ( ), collision centrality, and event multiplicity. They are extracted using two complementary methods: two-particle correlations with a template-fit subtraction of short-range nonflow contributions, and four-particle subevent cumulants, which intrinsically suppress nonflow effects and provide sensitivity to flow fluctuations. The results show a clear hierarchy and a nonmonotonic dependence on , reaching a maximum around , consistent with trends observed in heavy-ion collisions. Detailed comparisons between the two collision systems reveal an enhanced in central collisions, consistent with theory expectations based on the predicted prolate deformation of neon nuclei, in contrast to the slightly tetrahedral structure predicted for oxygen. The four-particle cumulant results highlight strong event-by-event fluctuations and provide the greatest sensitivity to nuclear shape effects. These measurements can place new constraints on the initial geometry and the hydrodynamic response in light-ion collisions, offering valuable input for models of nuclear structure.

Aad, G↗
DOE OSTI2025

Measurement of the azimuthal anisotropy of charged particles in $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV $^{16}$O$+^{16}$O and $^{20}$Ne$+^{20}$Ne collisions with the ATLAS detector

This paper presents the first measurements of the azimuthal anisotropy coefficients $v_{n}$, which quantify the $n^{\mathrm{th}}$-order Fourier modulation of charged-particle azimuthal distributions, for $n=2$-4 in $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV $\mathrm{^{16}O}+\mathrm{^{16}O}$ and $\mathrm{^{20}Ne}+\mathrm{^{20}Ne}$ collisions recorded with the ATLAS detector at the Large Hadron Collider in 2025. The $v_{n}$ coefficients are measured as a function of transverse momentum ($p_{\mathrm{T}}$), collision centrality, and event multiplicity. They are extracted using two complementary methods: two-particle correlations with a template-fit subtraction of short-range non-flow contributions, and four-particle subevent cumulants, which intrinsically suppress non-flow effects and provide sensitivity to flow fluctuations. The results show a clear hierarchy $v_{2} > v_{3} > v_{4}$ and a non-monotonic dependence on $p_{\mathrm{T}}$, reaching a maximum around 2 GeV, consistent with trends observed in heavy-ion collisions. Detailed comparisons between the two collision systems reveal an enhanced $v_{2}$ in central $\mathrm{^{20}Ne}+\mathrm{^{20}Ne}$ collisions, consistent with theory expectations based on the predicted prolate deformation of neon nuclei, in contrast to the slightly tetrahedral structure predicted for oxygen. The four-particle cumulant results highlight strong event-by-event fluctuations and provide the greatest sensitivity to nuclear shape effects. These measurements can place new constraints on the initial geometry and the hydrodynamic response in light-ion collisions, offering valuable input for models of nuclear structure.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Atomically Precise Nanoclusters as Co‐Catalysts for Light‐Activated Microswimmer Motility

Microswimmers are self-propelled particles that navigate fluid environments, offering significant potential for applications in environmental pollutant decomposition, biosensing, and targeted drug delivery. Their performance relies on engineered catalytic surfaces. Gold nanoclusters (AuNCs), with atomically precise structures, tunable optical properties, and high surface area-to-volume ratio, provide a new optimal catalyst for enhancing microswimmer propulsion. Unlike bulk gold or nanoparticles, AuNCs may deliver tunable photocatalytic activity and increased catalytic specificity, making them ideal co-catalysts for hybrid microswimmers. For the first time, this study combines AuNCs with TiO 2 /Cr 2 O 3 Janus microswimmers, combining the unique properties of both materials. This hybrid system capitalizes on the tuned optical properties of AuNCs and their role as co-catalysts with TiO 2 , driving enhanced photocatalytic performance under ultraviolet (UV) excitation. Using motion analysis, it is shown that the AuNC-microswimmers exhibit significantly greater propulsion and mean squared displacement (MSD) as compared to controls. These findings suggest that the integration of nanoclusters with semiconductor materials enables state of the art, light-switchable microswimmers. These AuNC-microswimmer systems may thus offer new opportunities for environmental catalysis and other applications, providing precise control over catalytic and motile behaviors at the microscale.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Application of Superconducting Cavities as Ultra-Sensitive RF Photon Detectors

Superconducting radio frequency (SRF) cavities are the world’s most efficient engineered oscillators, and they have long been employed for extremely high efficiency transfer of energy to beams of charged particles. Decades of R&D for particle accelerators have led to modern treatments for SRF cavities that achieve higher performance than was previously possible. Advanced SRF cavities using particle accelerator technology are now being used to search for new physics, including dark matter and gravitational waves. The extremely high Q makes it possible to search for very small signals from photons in the radio frequency range, and the extremely high electric fields makes it possible to perform experiments that involve pumping one mode of a cavity in order to search for power transfer mediated by new physics. This talk will present novel experiments that employ SRF cavities, including searches for axions and dark photons dark matter, light-shining-through-walls, and high frequency gravitational waves. Results to be presented include searches with world record sensitivity.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Precision spectroscopy of nuclear decays using quantum optomechanical sensors

This project developed and demonstrated a fundamentally new way to detect individual nuclear decays: rather than capturing the energy that decay products deposit in a detector, we measure the tiny mechanical recoil of the entire micron- or nanometer-sized particle in which the decaying nucleus is embedded. Because momentum is conserved, this approach is sensitive even to neutral, weakly interacting particles, including neutrinos, that escape conventional detectors. During the award, the Yale group reported the first-ever mechanical detection of single nuclear decays, a result featured widely in the scientific press, and pushed the sensitivity of smaller levitated nanoparticles into the quantum measurement regime, reaching an impulse resolution within a factor of five of the fundamental Standard Quantum Limit (SQL), good enough in principle to detect the momentum kicked to the particle by a single emitted neutrino. In parallel, the LBNL group developed the theory of quantum-enhanced (sub-SQL) readout tailored to this experiment, showing how squeezed light can push the sensitivity below the SQL. Together these results establish levitated optomechanical sensors as a new tool for precision nuclear decay spectroscopy, with further applications in neutrino physics, quantum metrology, and nuclear forensics and safeguards.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

The impact of new d(p,γ)3 rates on Big Bang Nucleosynthesis

We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the d(p,γ) 3 He cross section by the LUNA Collaboration. These have an important effect on the primordial abundance of D/H which is also sensitive to the baryon density at the time of BBN. We have re-evaluated the thermal rate for this reaction, using a world average of cross section data, which we describe with model-independent polynomials; our results are in good agreement with a similar analysis by LUNA. We then perform a full likelihood analysis combining BBN and Planck cosmic microwave background (CMB) likelihood chains using the new rate combined with previous measurements and compare with the results using previous rates. Concordance between BBN and CMB measurements of the anisotropy spectrum using the old rates was excellent. The predicted deuterium abundance at the Planck value of the baryon density was (D/H) BBN+CMB old = (2.57 ± 0.13) × 10 –5 which can be compared with the value determined from quasar absorption systems (D/H) obs = (2.55 ± 0.03) × 10 –5 . Using the new rates we find (D/H) BBN+CMB = (2.51 ± 0.11) × 10 –5 . We thus find consistency among BBN theory, deuterium and 4He observations, and the CMB, when using reaction rates fit in our data-driven approach. We also find that the new reaction data tightens the constraints on the number of relativistic degrees of freedom during BBN, giving the effective number of light neutrino species N ν = 2.880 ± 0.144 in good agreement with the Standard Model of particle physics. Lastly, we note that the observed deuterium abundance continues to be more precise than the BBN+CMB prediction, whose error budget is now dominated by d(d,n) 3 He and d(d,p) 3 H.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Impact of anatomical fractionation of corn stover on hammer mill throughput and energy consumption

The goal of this Case Study was to quantify the impacts of variable moisture and ash on hammer mill throughput and energy consumption and on loss of very wet stover that causes failures in the first stage grinder and that are not able to be fed to conversion, as compared to a status quo Base Case system. Also considered was convertible carbohydrate content (minimum total carbohydrate specification) and maximum ash content and the delivered feedstock cost impacts of not being able to feed stover not meeting the total carbohydrate specification to the conversion reactor. Laboratory data on the impacts of moisture content and tissue fraction on throughput and energy consumption in a stage 2 hammer mill were received from FCIC Subtask 5.1. Additional air classifier throughput, energy consumption and separation efficiency data were obtained from FCIC Subtask 5.1 for the new air classifier, which has three exit streams (lights, middle and heavies). These data were utilized to develop the necessary response surface equations to perform throughput analysis using discrete event simulation. Because the ash contents and particle sizes had not been analyzed in the laboratory at the time of the model runs, we assumed that the ash distributed proportionally with total mass into the lights and heavies in an air classifier having two exit streams (lights and heavies) and that the lights fraction from the air classifier was not removed. Key takeaways from this Case Study are that due to lower energy consumption, it is more cost effective to hammer mill fractionated corn stover tissues than whole stover. Reduction of grinding energy was significant and may possibly be connected to particle-particle interactions in the grinder that lead to increased residence time of leaves and husks, resulting in decreased throughput and higher generation of fines when milling whole stover. While we did not see significant impacts to throughput, this was due to moisture failures of the first stage grinder in each system dominating failures and downtime. The operating cost savings of reduced grinding energy savings in the second stage hammer mills alone was high enough to offset the added capital cost of the air classifier and extra grinding line.

09 BIOMASS FUELS↗
DOE OSTI2023

Impact of Anatomical Fractionation of Corn Stover on Hammer Mill Throughput and Energy Consumption

The goal of this Case Study was to quantify the impacts of variable moisture and ash on hammer mill throughput and energy consumption and on loss of very wet stover that causes failures in the first stage grinder and that are not able to be fed to conversion, as compared to a status quo Base Case system. Also considered was convertible carbohydrate content (minimum total carbohydrate specification), maximum ash content and the delivered feedstock cost impacts of not being able to feed stover that did not meet the total carbohydrate specification to the conversion reactor. Laboratory data on the impacts of moisture content and tissue fraction on throughput and energy consumption in a stage 2 hammer mill were received from FCIC Subtask 5.1: Preprocessing, Corn Stover Preprocessing (Neal Yancey and Sergio Hernandez, INL). Additional air classifier throughput, energy consumption and separation efficiency data were obtained from FCIC Subtask 5.1 (Neal Yancey, INL) for the new air classifier, which has three exit streams (lights, middle and heavies). These data were utilized to develop the necessary response surface equations to perform throughput analysis using discrete event simulation. Because the ash contents and particle sizes had not been analyzed in the laboratory at the time of the model runs, we assumed that the ash distributed proportionally with total mass into the lights and heavies in an air classifier having two exit streams (lights and heavies) and that the lights fraction from the air classifier was not removed.

ash content↗
DOE OSTI2023

High-Performance Coal-Based Commercial Facade Panels and Architectural Components (Phase I Final Report)

Semplastics has developed, tested, and documented the viability for commercialization of a new class of composite architectural panel materials that use coal as the primary constituent. This project produced sample panels using these novel materials that comprise 55% coal by mass (71% carbon by mass) and are comparable in dimensions to commercially available materials, while displaying superior mechanical strength, significant weight savings, and better insulating ability at a competitive cost. Phase I moved this coal-based composite materials technology from a Technology Readiness Level (TRL) of 3 to TRL 5. Semplastics’ new coal-based composite materials display an array of high-performance characteristics, including light weight, mechanical durability, temperature stability, and water resistance. These new materials require less energy to produce than comparable commercial products and could be manufactured on existing conventional plastic resin processing equipment in commercial quantities. The coal particles are completely encapsulated in ceramic from a polymer-derived ceramic (PDC) precursor, then bonded together by another inorganic resin. The material can be molded and cured to produce fireproof components such as ceiling panels, facades, and extruded underlayment, blocking, and backer boards, as well as other architectural design components such as moldings. The project included the production of sample panels for proof of concept, testing of the panels to show their improved characteristics, and development of a scale-up strategy to demonstrate the viability of the coal-based panels as a commercial alternative to existing building materials.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Simultaneous measurement of organic scintillator response to carbon and proton recoils

Organic scintillators are widely used for neutron detection in both basic nuclear physics and applications. While the proton light yield of organic scintillators has been extensively studied, measurements of the light yield from neutron interactions with carbon nuclei are scarce. Demonstrate a new approach for the simultaneous measurement of the proton and carbon light yield of organic scintillators. Provide new carbon light yield data for the EJ-309 liquid and EJ-204 plastic organic scintillators. A 33-MeV 2 H + beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory was impinged upon a 3-mm-thick Be target to produce a high-flux, broad-spectrum neutron beam. The double time-of-flight technique was extended to simultaneously measure the proton and carbon light yields of the organic scintillators, wherein the light output associated with the recoil particle was determined using np and nC elastic scattering kinematics. The proton and carbon light yield relations of the EJ-309 liquid and EJ-204 plastic organic scintillators were measured over a recoil energy range of approximately 0.3 to 1 MeV and 2 to 5 MeV, respectively, for EJ-309, and 0.2 to 0.5 MeV and 1 to 4 MeV, respectively, for EJ-204. Furthermore, these data provide new insight into the ionization quenching effect in organic scintillators and key input for simulation of the response of organic scintillators for both basic science and a broad range of applications.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

A review of NEST models for liquid xenon and an exhaustive comparison with other approaches

This paper discusses the microphysical simulation of interactions in liquid xenon, the active detector medium in many leading rare-event searches for new physics, and describes experimental observables useful for understanding detector performance. The scintillation and ionization yield distributions for signal and background are presented using the Noble Element Simulation Technique (NEST), a toolkit based on experimental data and simple empirical formulas, which mimic previous microphysics modeling but are guided by data. The NEST models for light and charge production as a function of the particle type, energy, and electric field are reviewed, along with models for energy resolution and final pulse areas. NEST is compared with other models or sets of models and validated against real data, with several specific examples drawn from XENON, ZEPLIN, LUX, LZ, PandaX, and table-top experiments used for calibrations.

WIMPs↗
DOE OSTI2022

Light scalars in neutron star mergers

Due to their unique set of multimessenger signals, neutron star mergers have emerged as a novel environment for studies of new physics beyond the Standard Model (SM). As a case study, we consider the simplest extension of the SM scalar sector involving a light CP-even scalar singlet S mixing with the SM Higgs boson. These S particles can be produced abundantly in neutron star mergers via the nucleon bremsstrahlung process. Here, we show that the S particles may either be trapped in or stream freely out of the merger remnant, depending on the S mass, its mixing with the SM Higgs boson, and the temperature and baryon density in the merger. In the free-streaming region, the scalar S will provide an extra channel to cool down the merger remnant, with cooling timescales as small as Script O(ms). On the other hand, in the trapped region, the Bose gas of S particles could contribute a larger thermal conductivity than the trapped neutrinos in some parts of the parameter space, thus leading to faster thermal equilibration than expected. Therefore, future observations of the early postmerger phase of a neutron star merger could effectively probe a unique range of the S parameter space, largely complementary to the existing and future laboratory and supernova limits. In view of these results, we hope the merger simulation community will be motivated to implement the effects of light CP-even scalars into their simulations in both the free-streaming and trapped regimes.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Search for dark matter produced in association with a Higgs boson decaying to bottom quarks in proton-proton collisions at $\sqrt{s}=13$ TeV

A search for dark matter particles produced in association with a Higgs boson decaying to a bottom quark-antiquark pair in proton-proton collisions at $\sqrt{s}=13$ TeV is presented. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 101 fb −1 . The analysis is performed in exclusive categories targeting both Lorentz-boosted (merged) and resolved 𝑏 jet pair topologies, covering a wide range of Higgs boson transverse momentum. A statistical combination is made with a previous search using data collected in 2016 and corresponding to an integrated luminosity of 35.9 fb −1 . The observed data agree with the standard model background predictions. Constraints are placed on models predicting new particles or interactions, such as those in the simplified frameworks of baryonic-𝑍′ and 2⁢HDM + 𝑎, where the latter is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the production cross section for these models. For the baryonic-𝑍′ model, 𝑍′ boson masses below 2.25 TeV are excluded for a dark matter particle candidate mass of 1 GeV. In the 2⁢HDM + 𝑎 model, heavy pseudoscalar masses between 850 and 1300 GeV are excluded for a light pseudoscalar mass of 350 GeV.

Hayrapetyan, A. [Yerevan Physics Institute]↗
DOE OSTI2022

Unleashing the full power of LHCb to probe stealth new physics

In this paper, we describe the potential of the LHCb experiment to detect stealth physics. This refers to dynamics beyond the standard model that would elude searches that focus on energetic objects or precision measurements of known processes. Stealth signatures include long-lived particles and light resonances that are produced very rarely or together with overwhelming backgrounds. We will discuss why LHCb is equipped to discover this kind of physics at the Large Hadron Collider and provide examples of well-motivated theoretical models that can be probed with great detail at the experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Design, construction, and operation of a 1-ton Water-based Liquid scintillator detector at Brookhaven National Laboratory

Water-based liquid scintillators (WbLS) are a new class of detector materials that provide efficient and tunable detection of both Cherenkov and scintillation light. A massive WbLS neutrino detector with suitable photosensor coverage for low intensity light detection could therefore reconstruct the momentum of an energetic charged particle and also have enhanced low-energy sensitivity. These materials are also better suited for metal doping broadening the potential scientific utility. Here, we recently constructed and commissioned a 1-ton WbLS detector with good photosensor coverage and a capable data acquisition and calibration system. We intend to use this flexible detector system as a testbed for WbLS R&D. In this paper we give an overview of the 1-ton system and provide some early results.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Toward UV models of kinetic mixing and portal matter. VII. A light dark photon in the 3 𝑐 ⁢3 𝐿 ⁢1 𝐴 ⁢1 𝐵 model

The kinetic mixing (KM) portal, by which the Standard Model (SM) photon mixes with a light dark photon arising from a new 𝑈⁢(1) 𝐷 gauge group, allows for the possibility of viable scenarios of sub-GeV thermal dark matter with appropriately suppressed couplings to the SM. This KM can only occur if particles having both SM and dark quantum numbers, here termed portal matter, also exist. The presence of such types of states and the strong suggestion of a need to embed 𝑈⁢(1) 𝐷 into a non-Abelian gauge structure not too far above the TeV scale based on the renormalization-group equation running of the 𝑈⁢(1)𝐷 gauge coupling is potentially indicative of an enlarged group linking together the visible and dark sectors. The gauge group 𝐺 = 𝑆⁢𝑈⁢(3) 𝑐 × 𝑆⁢𝑈⁢(3) 𝐿 × 𝑈⁢(1) 𝐴 × 𝑈⁢(1) 𝐵 = 3 𝑐 ⁢3 𝐿 ⁢1 𝐴 ⁢1 𝐵 is perhaps the simplest setup wherein the SM and dark interactions are partially unified in a non-Abelian fashion that is not a simple product group of the form 𝐺 = 𝐺 SM × 𝐺 𝐷 encountered frequently in earlier work. The present paper describes the implications and phenomenology of this type of setup.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Investigating Electro-Nuclear Interactions in a New Dark Matter Search

Electro-nuclear (EN) interactions are interactions in which an incident electron collides with a nucleus, scattering the electron and creating byproduct particles. Such interactions are of interest to neutrino physicists, who use EN interactions to inform model building of neutrino-nucleus interactions. The Light Dark Matter Experiment (LDMX) is a small-scale, fixed-target, electron beam experiment which seeks to probe for dark matter and mediator particle production in the sub-GeV mass region. The 8GeV LDMX electron beam will serve as an opportunity to study electro-nuclear interactions in their final states in the multi-GeV region. LDMX’s missing energy trigger however, will not be sufficient to efficiently capture EN interactions. An additional trigger needs to be created. Using simulated background events, including EN interactions, for the LDMX experiment, a trigger on momentum was developed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗