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All sources NASA NTRS DOE OSTI

DOE OSTI2024

Energy loss of a heavy fermion in a collisional QED plasma

We compute the energy loss of heavy fermions moving in a plasma, taking into account the modification of the photon collective modes induced by collisions using a Bhatnagar-Gross–Krook collisional kernel. We include contributions from both hard and soft scatterings of the heavy fermion using a collisionally modified hard-thermal-loop resummed propagator. Using this method, one does not need to introduce a separation scale between hard- and soft-momentum exchanges. To place our calculation in context, we review other theoretical approaches to computing the collisional energy loss of fermions and discuss the systematics and results obtained in each approach compared to using a resummed propagator for both hard and soft momentum exchanges. Our final results indicate that self-consistently including the effect of collisions in the self-energies of the resummed propagator results in an increased energy loss compared to using collisionless hard-thermal-loop propagators. The effect becomes larger as the magnitude of the coupling constant and the velocity of the fermion increase. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

NASA NTRS1998

The Effect of Interruptions on Part 121 Air Carrier Operations

The primary purpose of this study was to determine the relative priorities of various events and activities by examining the probability that a given activity was interrupted by a given event. The analysis will begin by providing frequency of interruption data by crew position (captain versus first officer) and event type. Any differences in the pattern of interruptions between the first officers and the captains will be explored and interpreted in terms of standard operating procedures. Subsequent data analyses will focus on comparing the frequency of interruptions for different types of activities and for the same activities under normal versus emergency conditions. Briefings and checklists will receive particular attention. The frequency with which specific activities are interrupted under multiple- versus single-task conditions also will be examined; because the majority of multiple-task data were obtained under laboratory conditions, LOFT-type tapes offer a unique opportunity to examine concurrent task performance under 'real-world' conditions. A second purpose of this study is to examine the effects of the interruptions on performance. More specifically, when possible, the time to resume specific activities will be compared to determine if pilots are slower to resume certain types of activities. Errors in resumption or failures to resume specific activities will be noted and any patterns in these errors will be identified. Again, particular attention will be given to the effects of interruptions on the completion of checklists and briefings. Other types of errors and missed events (i.e., the crew should have responded to the event but did not) will be examined. Any methodology using interruptions to examine task prioritization must be able to identify when an interruption has occurred and describe the ongoing activities that were interrupted. Both of these methodological problems are discussed In detail in the following section,

Damos, Diane L.↗

NASA NTRS1996

Alterations of Body Mass Gain of Neonates (P7&P14) During Certrifugation AT 2G

Previous research has shown animal body mass to be significantly affected by centrifugation. At the onset of centrifugation, animals have a selective loss of fat, causing an initial body mass loss. Body mass gain will resume at the same rate as uncentrifuged animals, but this subsequent gain will be lower. For this study, two different ages of Sprague Hawley neonate families were observed during centrifugation. Eight litters (dam with eight neonates) of postnatal day (PN) seven and four litters (dam with ten neonates) of PN 14 were separated into two separate groups each, centrifuge (+2G(sub z)) and environmental controls (EC) and placed into either the centrifuge or an animal holding unit in the centrifuge rotunda for a total of 16 days. P7: Total litter start mass of +2G(sub z) litter = 138.90 g/end = 311.0 g EC litter = 150.85 g/end = 516.9 g. P14: Total litter start mass of +2G(sub z) litter = 287.70 g/end = 762.5g; EC litter = 245 g/end = 942.9 g. An initial body mass loss was observed in both groups of +2G(sub z) animals for two days after the onset of centrifugation, but then an increase began to occur. Literature suggests adult animals at +2G(sub z), will have an initial loss, but will resume similar growth rates over time as compared to control animals. The P7 +2G(sub z) animals began to gain body mass, but showed a significantly slower growth rate than their EC animals for the duration of the test (pace). The P14 +2G(sub z) animals began to show similar growth rates to their EC after day nine. At day 16, both groups of +2Gz animals were significantly smaller than the EC animals (pace). At +2Gz, animals experience an initial body mass loss. Older animals are able to resume similar growth rates as their controls, but younger animals showed growth rates to be significantly reduced.

Baer, L. A.↗

NASA NTRS2018

Lessons Learned During the Transition of SORCE Science Operations to Daylight Only Operations

In July 2013, NASA's Solar Radiation and Climate Experiment experienced a battery anomaly which placed it into safemode halting all science observations. Initial attempts to recover the spacecraft to an operational configuration failed due to the reduced capacity of the battery. As the keystone mission for measuring total solar irradiance, and the cornerstone mission for measuring the solar spectral irradiance there was a strong motivation for developing a new operations concept that would allow SORCE to resume daily measurements of the Sun. The operations team faced many challenges over the next several months. For a five-day period in late 2013 the operations team was able resume science observations to cross-calibrate SORCE data with a new instrument launched in November 2013. After the cross-calibration campaign was completed a new operations concept was deployed which allowed SORCE to perform daylight only operations. In this mode of operations all non-essential components are powered off at each eclipse entry and then turned back on at sunrise. In March 2014 SORCE resumed making daily measurements of the Sun. This paper will review the events and lessons learned from the six-month recovery effort.

Spacecraft Anomaly↗

DOE OSTI2023

Transverse momentum resummation at N$^{3}$LL+NNLO for diboson processes

Diboson processes are one of the most accessible and stringent probes of the electroweak gauge structure of the Standard Model at the LHC. They will be probed at the percent level at the high-luminosity LHC, challenging current theory predictions. We present transverse momentum resummed calculations at N$^{3}$LL+NNLO for the processes ZZ, WZ, WH and ZH, compare our predictions with most recent LHC data and present predictions at 13.6 TeV including theory uncertainty estimates. For W$^{+}$W$^{−}$ production we further present jet-veto resummed results at N$^{3}$LL$_{p}$+NNLO. Our calculations will be made publicly available in the upcoming MCFM release and allow future analyses to take advantage of improved predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

Drell-Yan q T resummation of fiducial power corrections at N 3 LL

We consider Drell-Yan production pp → V*X → LX at small q T << Q, where q T and Q are the total transverse momentum and invariant mass of the leptonic final state L. Experimental measurements require fiducial cuts on L, which in general introduce enhanced, linear power corrections in q T /Q. We show that they can be unambiguously predicted from factorization, and resummed to the same order as the leading-power contribution. For the fiducial q T spectrum, they constitute the complete linear power corrections. We thus obtain predictions for the fiducial q T spectrum to N 3 LL and next-to-leading-power in q T /Q. Matching to full NNLO ($α$$^{2}_{s}$), we find that the linear power corrections are indeed the dominant ones, and once included by factorization, the remaining fixed-order corrections become almost negligible below q T ≲ 40 GeV. We also discuss the implications for more complicated observables, and provide predictions for the fiducial Φ* spectrum at N 3 LL+NNLO. We find excellent agreement with ATLAS and CMS measurements of q T and Φ*. We also consider the $p$$^{ℓ}_{T}$ spectrum. We show that it develops leptonic power corrections in q T /(Q – 2$p$$^{ℓ}_{T}$), which diverge near the Jacobian peak $p$$^{ℓ}_{T}$ ~ Q/2 and must be kept to all powers to obtain a meaningful result there. Doing so, we obtain for the first time an analytically resummed result for the $p$$^{ℓ}_{T}$ spectrum around the Jacobian peak at N 3 LL+NNLO. Our method is based on performing a complete tensor decomposition for hadronic and leptonic tensors. We show that in practice this is equivalent to often-used recoil prescriptions, for which our results now provide rigorous, formal justification. Our tensor decomposition yields nine Lorentz-scalar hadronic structure functions, which for Z/γ* → ℓℓ or W → ℓν directly map onto the commonly used angular coefficients, but also holds for arbitrary leptonic final states. In particular, for suitably defined Born-projected leptons it still yields a LO-like angular decomposition even when including QED final-state radiation. Finally, we also discuss the application to q T subtractions. Including the unambiguously predicted fiducial power corrections significantly improves their performance, and in particular makes them applicable near kinematic edges where they otherwise break down due to large leptonic power corrections.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Refining the GENEVA method for Higgs boson production via gluon fusion

We describe a number of improvements to the Geneva method for matching NNLO calculations to parton shower programs. In particular, we detail changes to the resummed calculation used in the matching procedure, including disentangling the cross section dependence on factorisation and beam scales, and an improved treatment of timelike logarithms. We also discuss modifications in the implementation of the splitting functions which serve to make the resummed calculation differential in the higher multiplicity phase space. These changes improve the stability of the numerical cancellation of the nonsingular term at small values of the resolution parameter. As a case study, we consider the gluon-initiated Higgs boson production process gg → H. We validate the NNLO accuracy of our predictions against independent calculations, and compare our showered and hadronised results with recent data taken at the ATLAS and CMS experiments in the diphoton decay channel, finding good agreement.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Subleading power resummation of rapidity logarithms: the energy-energy correlator in $ \mathcal{N} $ = 4 SYM

We derive and solve renormalization group equations that allow for the resummation of subleading power rapidity logarithms. Our equations involve operator mixing into a new class of operators, which we term the “rapidity identity operators”, that will generically appear at subleading power in problems involving both rapidity and virtuality scales. To illustrate our formalism, we analytically solve these equations to resum the power suppressed logarithms appearing in the back-to-back (double light cone) limit of the Energy-Energy Correlator (EEC) in $ \mathcal{N} $ = 4 super-Yang-Mills. These logarithms can also be extracted to $ \mathcal{O}\left({\alpha}_s^3\right) $ from a recent perturbative calculation, and we find perfect agreement to this order. Instead of the standard Sudakov exponential, our resummed result for the subleading power logarithms is expressed in terms of Dawson’s integral, with an argument related to the cusp anomalous dimension. We call this functional form “Dawson’s Sudakov”. Our formalism is widely applicable for the resummation of subleading power rapidity logarithms in other more phenomenologically relevant observables, such as the EEC in QCD, the p T spectrum for color singlet boson production at hadron colliders, and the resummation of power suppressed logarithms in the Regge limit.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Lattice QCD calculation of the pion distribution amplitude with domain wall fermions at physical pion mass

We present a direct lattice QCD calculation of the x-dependence of the pion distribution amplitude (DA), which is performed using the quasi-DA in large momentum effective theory on a domain-wall fermion ensemble at physical quark masses and spacing a ≈ 0.084 fm. The bare quais-DA matrix elements are renormalized in the hybrid scheme and matched to $\overline{MS}$ with a subtraction of the leading renormalon in the Wilson-line mass. For the first time, we include threshold resummation in the perturbative matching onto the light-cone DA, which resums the large logarithms in the soft gluon limit at next-to-next-to-leading log. The resummed results show controlled scale-variation uncertainty within the range of momentum fraction x ϵ [0.25, 0.75] at the largest pion momentum P z ≈ 1.85 GeV. In addition, we apply the same analysis to quasi-DAs from a highly-improved-staggered-quark ensemble at physical pion mass and a = 0.076 fm. By comparison we find with 2σ confidence level that the DA obtained from chiral fermions is flatter and lower near x = 0.5.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2021

The importance of kinematic twists and genuine saturation effects in dijet production at the Electron-Ion Collider

We compute the differential yield for quark anti-quark dijet production in high-energy electron-proton and electron-nucleus collisions at small x as a function of the relative momentum P ⊥ and momentum imbalance k ⊥ of the dijet system for different photon virtualities Q 2 , and study the elliptic and quadrangular anisotropies in the relative angle between P ⊥ and k ⊥ . We review and extend the analysis in [1], which compared the results of the Color Glass Condensate (CGC) with those obtained using the transverse momentum dependent (TMD) framework. In particular, we include in our comparison the improved TMD (ITMD) framework, which resums kinematic power corrections of the ratio k ⊥ over the hard scale Q ⊥ . By comparing ITMD and CGC results we are able to isolate genuine higher saturation contributions in the ratio Q s /Q ⊥ which are resummed only in the CGC. These saturation contributions are in addition to those in the Weizsäcker-Williams gluon TMD that appear in powers of Q s /k ⊥ . We provide numerical estimates of these contributions for inclusive dijet production at the future Electron-Ion Collider, and identify kinematic windows where they can become relevant in the measurement of dijet and dihadron azimuthal correlations. We argue that such measurements will allow the detailed experimental study of both kinematic power corrections and genuine gluon saturation effects.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

NNLL resummation of Sudakov shoulder logarithms in the heavy jet mass distribution

The heavy jet mass event shape has large perturbative logarithms near the leading order kinematic threshold at ρ = $\frac{1}{3}$. Catani and Webber named these logarithms Sudakov shoulders and resummed them at double-logarithmic level. A resummation to next-to-leading logarithmic level was achieved recently. Here, we extend the resummation using an effective field theory framework to next-to-next-to-leading logarithmic order and show how to combine it with the resummation of dijet logarithms. We also solve the open problem of an unphysical singularity in the resummed momentum space distribution, in a way similar to how it is resolved in the Drell-Yan q T spectrum: through a careful analysis of the kinematics and scale-setting in position space. The heavy jet mass Sudakov shoulder is the first observable that does not involve transverse momentum for which position space resummation is critical. These advances may lead to a more precise extraction of the strong coupling constant from e + e – data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

Phenomenological Model of Nonlinear Dynamics and Deterministic Chaotic Gas Migration in Bentonite: Experimental Evidence and Diagnostic Parameters

Understanding gas migration in compacted clay materials, e.g., bentonite and claystone, is important for the design and performance assessment of an engineered barrier system of a radioactive waste repository system, as well as many practical applications. Existing field and laboratory data on gas migration processes in low-permeability clay materials demonstrate the complexity of flow and transport processes, including various types of instabilities, caused by nonlinear dynamics of coupled processes of liquid–gas exchange, dilation, fracturing, fracture healing, etc., which cannot be described by classical models of fluid dynamics in porous media. We here show that the complexity of gas migration processes can be explained using a phenomenological concept of nonlinear dynamics and deterministic chaos theory. To do so, we analyzed gas pressure and gas influx (i.e., input) and outflux (i.e., output), recorded during the gas injection experiment in the compact Mx80-D bentonite sample, and calculated a set of the diagnostic parameters of nonlinear dynamics and chaos, such a global embedding dimension, a correlation dimension, an information dimension, and a spectrum of Lyapunov exponents, as well as plotted 2D and 3D pseudo-phase-space strange attractors, based on the univariate influx and outflux time series data. These results indicate the presence of phenomena of low-dimensional deterministic chaotic behavior of gas migration in bentonite. In particular, during the onset of gas influx in the bentonite core, before the breakthrough, the development of gas flow pathways is characterized by the process of chaotic gas diffusion. After the breakthrough, with inlet-to-outlet movement of gas, the prevailing process is chaotic advection. During the final phase of the experiment, with no influx to the sample, the relaxation pattern of gas outflux is resumed back to a process of chaotic diffusion. The types of data analysis and a proposed phenomenological model can be used to establish the basic principles of experimental data-gathering, modeling predictions, and a research design.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Hydrodynamic generators in relativistic kinetic theory

Here, we resum the nonequilibrium gradient corrections to a single-particle distribution function evolved by the Boltzmann equation in the relaxation time approximation (RTA). We first study a system undergoing Bjorken expansion and show that, for a constant relaxation time, the exact solution of the RTA Boltzmann equation at late times (i.e., after the decay of nonhydrodynamic modes) generates the Borel resummed Chapman-Enskog series. Extending this correspondence to systems without Bjorken symmetry, we construct a ( 3 + 1 )-dimensional hydrodynamic generator for RTA kinetic theory, which is an integral representation of the Chapman-Enskog series in the limit of vanishing nonhydrodynamic modes. Relaxing this limit, we discover at earlier times a set of nonhydrodynamic modes coupled to the RTA Chapman-Enskog expansion. Including the dynamics of these nonhydrodynamic modes is shown to control the emergence of hydrodynamics as an effective field theory description of nonequilibrium fluids, which works well even for far-off-equilibrium situations where the Knudsen number is initially large.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2024

Effects of renormalon scheme and perturbative scale choices on determinations of the strong coupling from e + e − event shapes

We study the role of renormalon cancellation schemes and perturbative scale choices in extractions of the strong coupling constant α s ( m Z ) and the leading nonperturbative shift parameter Ω 1 from resummed predictions of the e + e − event shape thrust. We calculate the thrust distribution to N L 3 L ′ resummed accuracy in soft-collinear effective theory (SCET) matched to the fixed-order O ( α s 2 ) prediction, and perform a new high-statistics computation of the O ( α s 3 ) matching in , although we do not include the latter in our final α s fits due to some observed systematics that require further investigation. We are primarily interested in testing the phenomenological impact sourced from varying amongst three renormalon cancellation schemes and two sets of perturbative scale profile choices. We then perform a global fit to available data spanning center-of-mass energies between 35–207 GeV in each scenario. Relevant subsets of our results are consistent with prior SCET-based extractions of α s ( m Z ) , but we are also led to a number of novel observations. Notably, we find that the combined effect of altering the renormalon cancellation scheme and profile parameters can lead to few-percent-level impacts on the extracted values in the α s − Ω 1 plane, indicating a potentially important systematic theory uncertainty that should be accounted for. We also observe that fits performed over windows dominated by dijet events are typically of a higher quality than those that extend into the far tails of the distributions, possibly motivating future fits focused more heavily in this region. Finally, we discuss how different estimates of the three-loop soft matching coefficient c S ˜ 3 can also lead to measurable changes in the fitted { α s , Ω 1 } values. Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Direct quarkonium production in DIS from a joint CGC and NRQCD framework

We compute the differential cross section for direct quarkonium production in high-energy electron-nucleus collisions at small 𝑥. Our computation is performed within the nonrelativistic QCD factorization formalism that separates the calculation into short distance coefficients and long distance matrix elements that depend on the color and spin of the state. We obtain the short distance coefficients of the production of the heavy quark pair within the framework of the color glass condensate effective field theory, which resums coherent multiple interactions of the heavy quark pair with the nucleus to all orders. Our results are expressed as the convolution of perturbatively calculable functions with multipoint lightlike Wilson line correlators. In the correlation limit, we establish the correspondence between our color glass condensate formulation with calculations employing the transverse momentum dependent (TMD) framework. We extend this correspondence by resumming kinematic power corrections within the improved TMD framework, which interpolates between the TMD formalism and 𝑘 ⊥ -factorization formalism. We present a detailed numerical analysis, focusing on 𝐽/𝜓 production in the kinematics accessible at the future Electron-Ion Collider, highlighting the importance of genuine higher-order saturation contributions when the electron collides with a large nucleus. Our results are also valid in the photoproduction limit where we expect the largest contribution from genuine higher-order saturation contributions which could be accessed in ultraperipheral collisions of relativistic heavy ions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

The diphoton $$q_T$$ spectrum at N$$^3$$LL$$^\prime $$ + NNLO

Abstract We present a $$q_T$$ q T -resummed calculation of diphoton production at order N $$^3$$ 3 LL $$^\prime $$ ′ + NNLO. To reach the primed level of accuracy we have implemented the recently published three-loop $${\mathcal {O}}(\alpha _s^3)$$ O ( α s 3 ) virtual corrections in the $$q\bar{q}$$ q q ¯ channel and the three-loop transverse momentum dependent beam functions and combined them with the existing infrastructure of , a code performing resummation at order N $${}^3$$ 3 LL. While the primed predictions are parametrically not more accurate, one typically observes from lower orders and other processes that they are the dominant effect of the next order. We include in both the $$q\bar{q}$$ q q ¯ and loop-induced gg channel the hard contributions consistently together at order $$\alpha _s^3$$ α s 3 and find that the resummed $$q\bar{q}$$ q q ¯ channel without matching stabilizes indeed. Due to large matching corrections and large contributions and uncertainties from the gg channel, the overall improvements are small though. We furthermore study the effect of hybrid-cone photon isolation and hard-scale choice on our fully matched results to describe the ATLAS $$\text {8}$$ 8 TeV data and find that the hybrid-cone isolation worsens agreement at small $$q_T$$ q T compared to smooth-cone isolation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

AmeriFlux US-UiD University of Illinois Restored Native Prairie

This is the AmeriFlux version of the carbon flux data for the site US-UiD University of Illinois Restored Native Prairie. Site Description - Site harvested annually with a mower during winters starting 2009. No fertilizer was applied, and not irrigated. Measurements were paused on March 23, 2016 and resumed in June 2024.

Bernacchi, Carl↗

DOE OSTI2020

Summary for Z-Petawatt Laser Activities (CY2019)

The high-energy upgrade of the Z-Petawatt (ZPW) laser system involved a shot hiatus starting in October 2018 to allow the installation of full-aperture optics in the chain, including in the main amplifier section as well as in the branches associated with the ZPW compressor and co-injection (the narrowband nanosecond operating mode that is co-bored with Z-Beamlet). Laser shots resumed May 1 st , with most shots since being in the ns mode to reduce complexity (while conditioning optics and calibrating diagnostics) as well as to support experimental requests. To facilitate experimental needs while a final full-sized co-injection optic was prepared, a sub-apertured beam has been used for experimental applications and a full-apertured beam has been used to validate the system. In the latter case, the beam is directed to a large calorimeter placed before branching occurs to the ZPW compressor or co-injection. As of September 2019, full-aperture co-injection shots had ramped up to 960J in 2.3ns, with many cross-calibrations being used to map out a relative humidity dependency in the leaky diagnostic mirror. Several such cross-calibration shots have been done using a chirped pulse seed as well, verifying that the diagnostic calibrations are valid in both broadband and narrow-band modes. Summarizing, since May 1 st of 2019 when shots resumed, 93 full system shots were performed with the ZPW laser. This included 2 co-injection shots with ZBL into Z (in support of MagLIF), 26 Pecos gas cell shots (in support of MagLIF), 11 Conchas gas cell shots (in support of UXI applications development), 6 Jemez shots (in support of backlighter development), and 48 calorimeter shots (in support of validating the system performance). Of these 93 shots, 45 shots were in conjunction with ZBL.

43 PARTICLE ACCELERATORS↗