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NASA NTRS2001

Doppler and Reflectivity Measurements at Two Closely-Spaced Frequencies

Spaceborne and airborne radars are limited with a respect to the mass and size of the instrument and the power available to operate it. As a consequence, dual-wavelength radars that require separate antennas and power amplifiers are expensive and often impractical. However, if the frequency difference can be reduced so that a single antenna and the same radio-frequency subsystem can be used for both frequencies, dual- wavelength Doppler measurements can be made with a radar of about the same size and mass as its single-frequency counterpart. In the first part of the paper we present calculations of the reflectivity factor differences as functions of the center frequency from 10 to 35 GHz and for frequency differences between -10% and 10% of the center frequency. The results indicate that differential-frequency operation at Ka-band frequencies (26.5 - 40 GHz) provides relatively strong differential signals if the frequencies can be separated by at least 5%. Unlike lower frequency operation, the differential signals at Ka-band (both reflectivity and Doppler) are directly related to the median mass diameter. An important feature of the differential mean Doppler is that it depends only on the drop-size dependent part of the radial velocity. In principle, the mean and mean differential Doppler data from a nadir-looking platform can be used to infer vertical air motion and characteristics of the particle size distribution. To test the instrument concept, the ER-2 Doppler radar was modified for differential frequency operation. Measurements by the modified radar, operating at frequencies of 9.1 GHz and 10 GHz, were made using an 8 degree zenith-pointing offset parabolic antenna. Simultaneous data were taken with an optical rain gauge and an impact disdrometer. Measured and DSD-estimated values of the differential dBZ mean Doppler are presented.

Meneghini, Robert↗

NASA NTRSDate not supplied

Using NASA Earth Observations to Identify Wildfire Impacts on Hydrologic Functions and Recovery in the Gila National Forest

Wildfires can dramatically influence both abiotic and biotic components of a landscape, including soil stability and chemistry; vegetation health, density, and composition; and water flow and quality. In addition to the immediate hazards posed by wildfires, subsequent hazards such as flooding and debris flow can impact the area. In New Mexico’s Gila National Forest, wildfire events have occurred with increasing frequency and severity over recent years, notably including the Whitewater Baldy Complex Fire (2012) and Silver Fire (2013), which burned over 290,000 acres and 138,698 acres, respectively, according to the Burned Area Emergency Response Team Executive Summary reports. Following a significant wildfire, land and resource management decisions are made, including when and where to focus vegetation and stream restoration efforts. This research is the result of a collaboration between the NASA DEVELOP National Program and the US Forest Service, which aimed to utilize NASA Earth observations to help inform those critical land management decisions. The project had two main objectives: 1) assess the efficacy of post-fire vegetation restoration efforts and 2) analyze the impact of burn events on the hydrology at the watershed-scale. To accomplish this first goal, data from Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI) were used to study the vegetation health over time of treated and non-treated burn areas. To accomplish the latter, various aspects of stream behavior were examined in relation to burn events, including the runoff coefficient and “flashiness” of streams based on USGS stream gauge data and Integrated Multi-satelllite Retrievals for GPM (IMERG) precipitation data. This will allow land managers to better understand the complex ecological relationship between the cascading effects after wildfire and the greater forest ecosystem.

Madeline Allen↗

DOE OSTI2024

Universal Bound on Effective Central Charge and Its Saturation

The effective central charge (denoted by 𝑐 eff ) is a measure of entanglement through a conformal interface, while the transmission coefficient (encoded in the coefficient 𝑐 𝐿⁢𝑅 of the two-point function of the energy-momentum tensor across the interface) is a measure of energy transmission through the interface. It has been pointed out that these two are generally different. In this Letter, we propose the inequalities, 0 ≤ 𝑐 𝐿⁢𝑅 ≤ 𝑐 eff ≤ min⁡(𝑐 𝐿 ,𝑐 𝑅 ). They have the simple but important implication that the amount of energy transmission can never exceed the amount of information transmission. We verify them using the AdS/CFT correspondence, using the perturbation method, and in examples beyond holography. We also show that these inequalities are sharp by constructing a class of interfaces that saturate them.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

NASA NTRS1989

Ecological applications of high resolution spectrometry

Future directions of NASA's space program plans include a significant effort at studying the Earth as a system of interrelated ecosystems. As part of NASA's Earth Observing System (Eos) Program a series of space platforms will be launched and operated to study the Earth with a variety of active and passive instruments. Several of the Eos instruments will be capable of imaging the planet's surface reflectance on a large number of very narrow portions of the solar spectrum. After the development of appropriate algorithms, this reflectance information will be used to determine key parameters about the structure and function of terrestrial and aquatic ecosystems and the pattern and processes of those systems across large areas of the globe. Algorithm development applicable to terrestrial systems will permit the inference of ecological processes from high resolution spectrometry data, similar to that to be forthcoming from the Eos mission. The first summer was spent working with tropical soils and relating their reflectance characteristics to particle size, iron content, and color. This summer the emphasis is on vegetation and work was begun with the Forest Ecosystems Dynamics Project in the Earth Resources Branch where both optical and radar characteristics of a mixed conifer/hardwood forest in Maine are being studied for use in a ecological modeling effort. A major series of aircraft overflights will take place throughout the summer. Laboratory and field spectrometers are used to measure the spectral reflectance of a hierarchy of vegetation from individual leaves to whole canopies for eventual modeling of their nutrient content using reflectance data. Key leaf/canopy parameters are being approximated including chlorophyll, nitrogen, phosphorus, water content, and leaf specific weight using high resolution spectrometry alone. Measurements are made of carbon exchange across the landscape for input to a spatial modeling effort to gauge production within the forest. A Geographic Information System approach is used to associate these data, images, and other collateral information for the forest into a database with a common projection suitable for spatial modeling.

Lawrence, William T.↗

NASA NTRS2014

A Preliminary Analysis of Precipitation Properties and Processes during NASA GPM IFloodS

The Iowa Flood Studies (IFloodS) is a NASA Global Precipitation Measurement (GPM) ground measurement campaign, which took place in eastern Iowa from May 1 to June 15, 2013. The goals of the field campaign were to collect detailed measurements of surface precipitation using ground instruments and advanced weather radars while simultaneously collecting data from satellites passing overhead. Data collected by the radars and other ground instruments, such as disdrometers and rain gauges, will be used to characterize precipitation properties throughout the vertical column, including the precipitation type (e.g., rain, graupel, hail, aggregates, ice crystals), precipitation amounts (e.g., rain rate), and the size and shape of raindrops. The impact of physical processes, such as aggregation, melting, breakup and coalescence on the measured liquid and ice precipitation properties will be investigated. These ground observations will ultimately be used to improve rainfall estimates from satellites and in particular the algorithms that interpret raw data for the upcoming GPM mission's Core Observatory satellite, which launches in 2014. The various precipitation data collected will eventually be used as input to flood forecasting models in an effort to improve capabilities and test the utility and limitations of satellite precipitation data for flood forecasting. In this preliminary study, the focus will be on analysis of NASA NPOL (S‐band, polarimetric) radar (e.g., radar reflectivity, differential reflectivity, differential phase, correlation coefficient) and NASA 2D Video Disdrometers (2DVDs) measurements. Quality control and processing of the radar and disdrometer data sets will be outlined. In analyzing preliminary cases, particular emphasis will be placed on 1) documenting the evolution of the rain drop size distribution (DSD) as a function of column melting processes and 2) assessing the impact of range on ground‐based polarimetric radar estimates of DSD properties.

Carey, Lawrence↗

NASA NTRS2011

High-Sensitivity, Broad-Range Vacuum Gauge Using Nanotubes for Micromachined Cavities

A broad-range vacuum gauge has been created by suspending a single-walled carbon nanotube (SWNT) (metallic or semiconducting) in a Schottky diode format or in a bridge conductor format, between two electrically charged mesas. SWNTs are highly sensitive to molecular collisions because of their extremely small diameters in the range of 1 to 3 nanometers. The measurement parameter will be the change in conductivity of SWNT due to decreasing rate of molecular collisions as the pressure inside a chamber decreases. The rate of heat removal approaches a saturation limit as the mean free path (m.f.p.) lengths of molecules increase due to decreasing pressure. Only those sensing elements that have a long relaxation time can produce a measureable response when m.f.p. of molecules increases (or time between two consecutive collisions increases). A suspended SWNT offers such a capability because of its one-dimensional nature and ultrasmall diameter. In the initial approach, similar architecture was used as that of a SWNT-Schottky diode that has been developed at JPL, and has its changing conductivity measured as the test chamber is pumped down from atmospheric pressure to high vacuum (10(exp -7) Torr). Continuous response of decreasing conductivity has been measured as a function of decreasing pressure (SWNT is a negative thermal coefficient material) from atmosphere to less than 10(exp -6) Torr. A measureable current change in the hundreds of nA range has been recorded in the 10(exp -6) Torr regime.

Manohara, Harish↗

NASA NTRS2004

Method Developed for Noninterference Measurement of Blade Damping

Although noninterference optical instrumentation has been previously used to monitor and measure rotor blade vibrations, it has not been used at the NASA Glenn Research Center for the determination of damping. This article describes such a measurement in Glenn's Spin Rig facility. The optical system was chosen because installation of the slip rig for this particular configuration was not feasible, ruling out strain gauge instrumentation. The shaft in this facility was suspended with two radial magnetic bearings, and the excitation was supplied to the bearings by a signal generator. For the first mode, the direction of excitation force was always perpendicular to the blade as described by Morrison. The preceding graph shows blade displacements, as measured by an optical probe during a frequency sweep designed to locate the first mode resonance. The resonance determines the frequency at which the shaft is excited. Because the sampling rate was fixed to only once per revolution with these transducers, and the first mode frequency was much larger than the rotational frequency, the data in this figure were undersampled with an apparent frequency that was only 1 Hz at the beginning of the sweep, about 14 Hz at the maximum amplitude, and about 20 Hz at the end of the sweep. The true excitation frequency varied during the sweep from 320 to 340 Hz, and the resonance occurred at 334 Hz. Damping is determined by applying a frequency burst to the shaft. Upon cessation of the burst, the blade undergoes free decay. The apparent damping is then obtained by a least squares fit of the theoretical cosine decay function through the experimental points. The following graph illustrates this procedure. Because of frequency aliasing, the apparent measured damping must be divided by the ratio of the true resonant frequency to the apparent measured frequency to obtain the true damping. Note that the contribution of the shaft vibration to the blade vibration could be neglected because it was shown that it is an order of magnitude smaller and that its decay is an order of magnitude faster.

Kurkov, Anatole P.↗

NASA NTRS2004

SiC-Based Miniature High-Temperature Cantilever Anemometer

The figure depicts a miniature cantilever-type anemometer that has been developed as a prototype of compact, relatively nonintrusive anemometers that can function at temperatures up to 600 C and that can be expected to be commercially mass-producible at low cost. The design of this anemometer, and especially the packaging aspect of the design, is intended to enable measurement of turbulence in the high-temperature, high-vibration environment of a turbine engine or in any similar environment. The main structural components of the anemometer include a single-crystal SiC cantilever and two polycrystalline SiC clamping plates, all made from chemical-vapor-deposited silicon carbide. Fabrication of these components from the same basic material eliminates thermal-expansion mismatch, which has introduced spurious thermomechanical stresses in cantilever-type anemometers of prior design. The clamping plates are heavily oxidized to improve electrical insulation at high temperature. A cavity that serves as a receptacle for the clamped end of the cantilever is etched into one end of one clamping plate. Trenches that collectively constitute a socket for a multipin electrical plug (for connection to external electronic circuitry) are etched into the opposite end of this clamping plate. Metal strips for electrical contact are deposited on one face of the other clamping plate. Piezoresistive single-crystal SiC thin-film strain gauges are etched in the n-type SiC epilayer in a Wheatstone-bridge configuration. Metal contact pads on the cantilever that extend into the clamping-receptacle area, are obtained by deposition and patterning using standard semiconductor photolithography and etching methods. The cantilever and the two clamping plates are assembled into a sandwich structure that is then clamped in a stainless-steel housing. The Wheatstone- bridge carrying SiC cantilever with the metal contact pads on the piezoresistors is slid into the receptacle in the bottom clamping plate. The top clamping plate is brought into contact with the bottom plate so that the narrow section of the metal strips on the top clamp plate aligns with the metal contact pads on the cantilever. When the parts are clamped together, the metal strips provide electrical connections between the Wheatstone-bridge contact points and the sides the trenches that constitute the socket for the multipin electrical plug. Hence, to connect the Wheatstone bridge to external circuitry for processing of the anemometer readout, one need only insert the plug in the socket. In operation, the cantilever end of the stainless-steel housing is mounted flush with an engine wall and the unclamped portion of the cantilever is exposed into the flow. The cantilever is deflected in direct proportion to the force induced by component of flow parallel to the engine wall and perpendicular to the broad exposed face of the cantilever. The maximum strain on the cantilever occurs at the clamped edge and is measured by the piezoresistors, which are located there. The corresponding changes in resistance manifest themselves in the output of the Wheatstone bridge.

Okojie, Robert S.↗

NASA NTRS1992

Cyclic axial-torsional deformation behavior of a cobalt-base superalloy

Multiaxial loading, especially at elevated temperature, can cause the inelastic response of a material to differ significantly from that predicted by simple flow rules, i.e., von Mises or Tresca. To quantify some of these differences, the cyclic high-temperature, deformation behavior of a wrought cobalt-based superalloy, Haynes 188, is investigated under combined axial and torsional loads. Haynes 188 is currently used in many aerospace gas turbine and rocket engine applications, e.g., the combustor liner for the T800 turboshaft engine for the RAH-66 Comanche helicopter and the liquid oxygen posts in the main injector of the space shuttle main engine. The deformation behavior of this material is assessed through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue data base has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gauge section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress versus engineering shear strain, axial strain versus engineering shear strain, and axial stress versus shear stress spaces are presented for cyclic, in-phase and out-of-phase, axial torsional tests. For in-phase tests three different values of the proportionality constant, lambda (ratio of engineering shear strain amplitude to axial strain amplitude), are examined, viz., 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 deg with lambda = 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase and out-of-phase axial-torsional fatigue tests. These comparisons are accomplished through simple Ramberg-Osgood type stress-strain functions for cyclic, axial stress-strain and shear stress-engineering shear strain curves.

Bonacuse, Peter J.↗

NASA NTRS2017

Ecological Study of Lagoons Surrounding the John F. Kennedy Space Center, Brevard County, Florida : Theses and Project Reports - Volume 2

Many of the detailed studies done in connection with Ecological Study of the Lagoons surrounding the John F. Kennedy Space Port were performed as Master's Thesis investigations by various graduate students enrolled at F. I. T. during and subsequent to the report. The scope and purpose of what we came to call "the KSC Baseline Study" caught the imagination and interest of our student body. Many who were not financially or otherwise connected with the project found their inspiration in studies that were directly connected with project, and thus added materially to the totality of the knowledge gained. An example of one such study is the first article included in this Volume, A Master's Thesis study performed by Shen Phillip Chen, who chose the site for his investigation so that his results would correlate with and extend the results of others. In addition to the Master's Theses contained in this Volume, six other graduate studies must be acknowledged here as contributing to this Report, although they have not reached the stage of final publication. Ms. Sandra Fettes has completed a study of the amounts of five trace metals in mangrove leaves from plants at various locations around the Kennedy Space Center. Mr. Bernard Cohenour has isolated and identified a number of oil consuming bacteria endemic in the waters of the Indian Rivers. Mr. Charles Waterhouse has analyzed historic data of tidal gauges in the lagoonal area and correlated it with wind field records. Mr. Renkert Meyer has measured the vertical and horizontal currents of the lagoons and is attempting an interpretation of them in terms of the wind field as a driving force. Mr. Richard Campbell has measured the rate of nitrogen fixation in both the water columns and the sediments under them in the lagoons. Mr. Craig Weiderhold has measured thl3 annual variations in the populations of benthic invertebrates in the lagoons. An integral part of the F. I. T. curriculum is a requirement that each undergraduate student perform an independent study during his Senior year and submit his results in the form and format of a professional scientific report. While none of these senior Project Reports have been included in this Volume because of space limitations, many of them aided significantly in the overall study. Typical of these were: light and dark bottle studies of the blue-green algae respiration; writing and executing computer studies comparing the water chemistry data from various sites; detection and identification of nitrogen fixation bacteria in the Indian River; measurement of dissolved oils and greases in the river, photographically recording the benthic life-forms found in the river bottom; measuring the vertical structure of drift and slope currents in too lagoons; and measurement of water level variations along the long axis of a lagoon as a function of wind stress. These articles are published as a part of this Final Report in an effort to make available for the record as much of the basic data as possible. The few articles published on the Indian River have in general not contained much detailed data, so that comparisons of current status to conditions of the past are difficult or impossible. A major effort of both the Oceanographic and Ecological communities for the past decade has been the retrieval and storage of basic data in order to permit determinations of trends or changes in baseline conditions. It is believed that the information compiled here will be of great value in any future investigations.

Source record↗

DOE OSTI2025

Towards a real-time computation of timelike hadronic vacuum polarization and light-by-light scattering: Schwinger Model tests

Hadronic vacuum polarization (HVP) and light-by-light scattering (HLBL) are crucial for evaluating the Standard Model predictions concerning the muon’s anomalous magnetic moment. However, direct first-principle lattice gauge theory-based calculations of these observables in the timelike region remain challenging. Discrepancies persist between lattice quantum chromodynamics (QCD) calculations in the spacelike region and dispersive approaches relying on experimental data parametrization from the timelike region. Here, we introduce a methodology employing 1+1-dimensional quantum electrodynamics (QED), i.e. the Schwinger Model, to investigate the HVP and HLBL. To that end, we use both tensor network techniques, specifically matrix product states, and classical emulators of digital quantum computers. Demonstrating feasibility in a simplified model, our approach sets the stage for future endeavors leveraging digital quantum computers.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS2017

Oxygen Candle Background for Subs and Space

"At any time and without warning, a submarine may have to remain submerged for several days on account of the presence of the enemy, or rough weather, or serious accident to the machinery. Fortunately such occurrences are rare; but every commanding officer must be prepared to meet such an emergency that will afford his men the greatest possible chance of survival." Reference (1) This quotation is taken from a review of submarine air purification technology published by the Bureau of Medicine and Surgery in 1919. At that time, the U.S. Navy had just begun to experiment with possible air purification devices and supplies of oxygen that might permit submarines to remain submerged longer that the untreated closed atmosphere would allow. Submariners were exposed to elevated levels of carbon dioxide and reduced levels of oxygen that would be considered completely unacceptable by current standards. It was a different world, but humans are still humans, and the requirements for safe and effective functioning in a self-contained environment are really unchanged. The maximum submergence time for submarines as published in that work was approximately 48 hours, reference (1) In early submarines, the preferred supply of oxygen was 1800 psig compressed gas bled into the boat as needed, references (1,2). The need for added oxygen was occasionally "measured" by the physiological impact on the crew rather than a reliable instrument, reference (1). The design of submarine oxygen supply was limited to approximately 25 day submerged operation, reference (2). It was not until 1958 that U.S. submarines were able to carry out dives beyond that period and necessitated new sources of oxygen, reference (2). A curious second source of oxygen at the time was compressed air vessels that were bled into the boat while "vitiated" air (air with reduced oxygen and elevated carbon dioxide) from the opposite end of the boat was compressed into waiting empty vessels, reference (1). The periodic use of pressurized air to control oxygen caused swings in ambient pressure that was uncomfortable to the crew, reference (1). As early as 1919, liquid oxygen was a commercially available product and its use on submarines was contemplated, reference (1). It is interesting that even at this date, 1919, the danger of oils or greases when exposed to compressed or liquid oxygen was recognized: "One precaution must be always taken. No oil or grease should be used in the gauge or fittings or a dangerous explosion may result."

Graf, John↗

NASA NTRS2003

Retrieval of Precipitation Profiles from Multiresolution, Multifrequency, Active and Passive Microwave Observations

In this study, a technique for estimating vertical profiles of precipitation from multifrequency, multiresolution active and passive microwave observations is investigated. The technique is applicable to the Tropical Rainfall Measuring Mission (TRMM) observations and it is based on models that simulate high-resolution brightness temperatures as functions of observed reflectivity profiles and a parameter related to the rain drop-size-distribution. The modeled high-resolution brightness temperatures are used to determine normalized brightness temperature polarizations at the microwave radiometer resolution. An optimal estimation procedure is employed to minimize the differences between the simulated and observed normalized polarizations by adjusting the drop-size-distribution parameter. The impact of other unknowns that are not independent variables in the optimal estimation but affect the retrievals is minimized through statistical parameterizations derived from cloud model simulations. The retrieval technique is investigated using TRMM observations collected during the Kwajalein Experiment (KWAJEX). These observations cover an area extending from 5 deg to deg N latitude and 166 deg to 172 deg E longitude from July to September 1999, and are coincident with various ground-based observations, facilitating a detailed analysis of the retrieved precipitation. Using the method developed in this study, precipitation estimates consistent with both the passive and active TRMM observations are obtained. Various parameters characterizing these estimates, i.e. the rain rate, the precipitation water content, the drop-size-distribution intercept, and the mass weighted mean drop diameter, are in good qualitative agreement with independent experimental and theoretical estimates. Combined rain estimates are in general higher than the official TRMM Precipitation Radar (PR) only estimates for the area and the period considered in the study. Ground-based precipitation estimates, derived from an analysis of rain gauge and ground radar data, are in better agreement with the combined estimates than with the TRMM PR-only estimates, which suggests that information useful for improving the radar-only estimates is contained in the brightness temperature data.

Grecu, Mircea↗

DOE OSTI2026

Filling the gap: hunting for vector bosons at the MUonE experiment with displaced decay signature

The upcoming MUonE experiment aims to precisely measure the running of the fine structure constant via elastic muon-electron scattering, to shed light on the current tension in the muon’s anomalous magnetic moment. In addition to its primary function as a precision experiment, MUonE also offers a unique testing ground to probe long-lived vector bosons. Such vector bosons can be produced via μe → μeV or μN → μNV scattering and decay into an electron/positron pair a few centimeters away from the interaction point. With its high-resolution tracking system and unique geometric design, MUonE is well-suited to reconstruct displaced vertices close to the target, allowing it to probe parameter space previously unattainable at colliders and longer-baseline beam dump experiments. We present a comprehensive study of the discovery potential of BSM vector boson mediators at the MUonE experiment. We show that MUonE can fill the long-standing gap in the parameter space of vector boson mediators with masses up to around 100 MeV.

Models for Dark Matter↗

DOE OSTI2025

Searches for New Physics With Muon Conversion at Fermilab and Triboson Production at the LHC

We report on several efforts to search for physics beyond the standard model of particle physics at broad energy scales. The Mu2e experiment at Fermilab will search for charged lepton flavor violation via the muon to electron conversion process, which is suppressed in the Standard Model. Mu2e will be operated at a low energy, yet can probe New Physics at very high mass scales (O(1e3 - 1e4 ) TeV). At high energies, the CMS experiment at the CERN LHC continues to deliver an impressive suite of Standard Model measurements and limits on a variety of New Physics signatures. Mu2e is under construction and slated to collect its first physics data in the coming years. This thesis describes work done during the construction phase of Mu2e and focuses on two critical areas: magnetic field modeling and statistical analysis. We describe a novel method for field modeling which we validate using a simulated dataset representing the expected magnetic field in the Detector Solenoid. This method blends a standard least-squares fitting technique that utilizes physically motivated analytical model functions with a novel physics informed network that is constructed to obey Maxwell’s equations. We show the technique can model the field with an accuracy of 10−7 despite the presence of injected noise in the pseudo-measurements at the 10−5 level. We then present preliminary results of the calibration of 3D Hall probes at the sub-10−4 level. These probes will be used to directly measure the Mu2e Detector Solenoid magnetic field on a sparse grid; these measurements serve as the input to the field model fitting. Finally, we describe the first implementation of both an unbinned shape analysis and a Bayesian interpretation applied to Mu2e pseudo-data. Up to 20% tighter limits can be set by the shape analysis compared to a standard cut & count analysis. The AlCap experiment collected data at PSI in 2015 to measure several important quantities related to nuclear muon capture on an aluminum target, which is a significant background process for Mu2e. The neutron emission from muon capture can introduce background hits in the Mu2e detectors and can increase radiation damage in various elements of the apparatus. We present measurements of the neutron group fluence and mean neutron multiplicity for muon capture on aluminum nuclei. Finally, we discuss an analysis of triboson production at CMS using an Effective Field Theory framework. Standard Model triboson production, which was first observed at CMS in 2020, has a relatively small cross section and provides direct access to both anomalous triple gauge couplings and quartic gauge couplings. These couplings, interpreted in the Standard Model Effective Field Theory, are studied in the present work. We target the boosted regime where the background rate is low and yields are enhanced when dimension-6 and dimension-8 Wilson coefficients are non-zero. We do not observe an excess in the data and therefore set bounds on the Wilson coefficients. For dimension-6 coefficients the tightest observed (expected) bounds are set on cW /Λ2 where Λ is the mass scale of new physics; the bounds are [−0.13, 0.12] TeV−2 ([−0.12, 0.12] TeV−2 ) at 95% CL. The tightest bounds in dimension-8 are set on fT,0 / Λ4 ; the observed (expected) bounds at 95% CL are [−0.63, 0.69] TeV−4 ([−0.54, 0.62] TeV−4 ). Additional results are presented which include scenarios where multiple Wilson coefficients are non-zero, the application of signal model clipping to address unitarity violation in Effective Field Theories, and a novel template fit developed for easier reinterpretation of our results.

Kampa, Cole Erik [Northwestern U. (main)] (ORCID:0↗

NASA NTRS2010

Transfer of Satellite Rainfall Uncertainty from Gauged to Ungauged Regions at Regional and Seasonal Timescales

Hydrologists and other users need to know the uncertainty of the satellite rainfall data sets across the range of time/space scales over the whole domain of the data set. Here, uncertainty' refers to the general concept of the deviation' of an estimate from the reference (or ground truth) where the deviation may be defined in multiple ways. This uncertainty information can provide insight to the user on the realistic limits of utility, such as hydrologic predictability, that can be achieved with these satellite rainfall data sets. However, satellite rainfall uncertainty estimation requires ground validation (GV) precipitation data. On the other hand, satellite data will be most useful over regions that lack GV data, for example developing countries. This paper addresses the open issues for developing an appropriate uncertainty transfer scheme that can routinely estimate various uncertainty metrics across the globe by leveraging a combination of spatially-dense GV data and temporally sparse surrogate (or proxy) GV data, such as the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar and the Global Precipitation Measurement (GPM) mission Dual-Frequency Precipitation Radar. The TRMM Multi-satellite Precipitation Analysis (TMPA) products over the US spanning a record of 6 years are used as a representative example of satellite rainfall. It is shown that there exists a quantifiable spatial structure in the uncertainty of satellite data for spatial interpolation. Probabilistic analysis of sampling offered by the existing constellation of passive microwave sensors indicate that transfer of uncertainty for hydrologic applications may be effective at daily time scales or higher during the GPM era. Finally, a commonly used spatial interpolation technique (kriging), that leverages the spatial correlation of estimation uncertainty, is assessed at climatologic, seasonal, monthly and weekly timescales. It is found that the effectiveness of kriging is sensitive to the type of uncertainty metric, time scale of transfer and the density of GV data within the transfer domain. Transfer accuracy is lowest at weekly timescales with the error doubling from monthly to weekly.However, at very low GV data density (<20% of the domain), the transfer accuracy is too low to show any distinction as a function of the timescale of transfer.

Tang, Ling↗

NASA NTRS2020

Multiwavelength Variability and Correlation Studies of Mrk 421 During Historically Low X-ray and Y-ray Activity in 2015–2016

We report a characterization of the multiband flux variability and correlations of the nearby (z=0.031) blazar Markarian 421(Mrk 421) using data from Mets ̈ahovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1TeV<1.7×10−12ph cm−2s−1) and in the 2–10 keV (X-ray) band (F2−10 keV<3.6×10−11erg cm−2s−1),during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E>0.1 TeV)γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our dataset with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9−6d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process.

Mrk 421↗

DOE OSTI2024

Scalable Circuits for Preparing Ground States on Digital Quantum Computers: The Schwinger Model Vacuum on 100 Qubits

The vacuum of the lattice Schwinger model is prepared on up to 100 qubits of IBM’s Eagle-processor quantum computers. A new algorithm to prepare the ground state of a gapped translationally invariant system on a quantum computer is presented, which we call “scalable circuits ADAPT-VQE” (SC-ADAPT-VQE). This algorithm uses the exponential decay of correlations between distant regions of the ground state, together with ADAPT-VQE, to construct quantum circuits for state preparation that can be scaled to arbitrarily large systems. These scalable circuits can be determined with use of classical computers, avoiding the challenging task of optimizing parameterized circuits on a quantum computer. SC-ADAPT-VQE is applied to the Schwinger model, and is shown to be systematically improvable, with an accuracy that converges exponentially with circuit depth. Both the structure of the circuits and the deviations of prepared wave functions are found to become independent of the number of spatial sites, L . This allows a controlled extrapolation of the circuits, determined with use of small or modest-sized systems, to arbitrarily large L . The circuits for the Schwinger model are determined on lattices up to L = 14 (28 qubits) with the Qiskit classical simulator, and are subsequently scaled up to prepare the L = 50 (100 qubits) vacuum on IBM’s 127-superconducting-qubit quantum computers ibm_brisbane and ibm_cusco. After introduction of an improved error-mitigation technique, which we call “operator decoherence renormalization”, the chiral condensate and charge-charge correlators obtained from the quantum computers are found to be in good agreement with classical matrix product state simulations. Published by the American Physical Society 2024

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗