Precise Detections of Solar Particle Events and a New View of the Moon
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Jody K. Wilson↗
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Detection of alpha particles in auroral phenomena.
Auroral energetic alpha particle to proton differential flux ratio after solar flare from rocket-borne detector and ground based photometer data
Eather, R. H.↗
ATS-6 - UCSD auroral particles experiment
The University of California at San Diego Auroral Particles Experiment aboard Applications Technology Satellite-6 (ATS-6) is discussed. The experiment is designed to investigate the time development of geomagnetic substorm particles, the confinement and loss of such particles, and the roles of plasma wave instabilities and characteristic system periodicities in substorm and general magnetospheric processes. The instrumentation includes a complement of five electrostatic charged particle detectors. Two detector assemblies are capable of rotation through 220 deg. The electrostatic curved plate energy/unit charge analyzers are ovoid, requiring particles to be bent only 55 deg to obtain azimuthal focusing. The inside of the plates is serrated to eliminate particles striking the sides. A post-analysis electrostatic lens consisting of two wire grids, one at the potential of the inner plate and one at the potential of ground, focuses particles strongly upon the center of the sensor. A spiraltron particle sensor detects the charged particles. The system has an energy range of five orders of magnitude with a lower extreme of less than 1 eV. Preliminary data are presented to illustrate phenomena which are observed as a result of the novel features described.
Mauk, B. H.↗
Particle Impact Noise Detection (PIND) test
Technique applies water-soluble ultrasonic couplant to transducer to facilitate acoustical nondestructive test for sealed and semisealed devices.
Reilly, W.↗
Neural Networks Analyze Data In Particle-Impact-Noise Tests
Electronic neural networks and computers put to use in analyzing data acquired in particle-impact-noise-detection (PIND) tests of packaged electronic components. PIND tests detect loose particles in packages that cause failures during subsequent operation of packages in presence of accelerations or other effects - for example, loose electrically conductive particles that bounce into positions in which they cause short circuits. Interpretation of test data more objective and accurate. Preliminary results suggest use of neural networks result in significant improvement in quality and reliability and decrease in cost of PIND testing.
Scaglione, Lois J.↗
Chemical Pollution from Combustion of Modern Spacecraft Materials
Fire is one of the most critical contingencies in spacecraft and any closed environment including submarines. Currently, NASA uses particle based technology to detect fires and hand-held combustion product monitors to track the clean-up and restoration of habitable cabin environment after the fire is extinguished. In the future, chemical detection could augment particle detection to eliminate frequent nuisance false alarms triggered by dust. In the interest of understanding combustion from both particulate and chemical generation, NASA Centers have been collaborating on combustion studies at White Sands Test Facility using modern spacecraft materials as fuels, and both old and new technology to measure the chemical and particulate products of combustion. The tests attempted to study smoldering pyrolysis at relatively low temperatures without ignition to flaming conditions. This paper will summarize the results of two 1-week long tests undertaken in 2012, focusing on the chemical products of combustion. The results confirm the key chemical products are carbon monoxide (CO), hydrogen cyanide (HCN), hydrogen fluoride (HF) and hydrogen chloride (HCl), whose concentrations depend on the particular material and test conditions. For example, modern aerospace wire insulation produces significant concentration of HF, which persists in the test chamber longer than anticipated. These compounds are the analytical targets identified for the development of new tunable diode laser based hand-held monitors, to replace the aging electrochemical sensor based devices currently in use on the International Space Station.
Mudgett, Paul D.↗
Measurement of the phase between strong and electromagnetic amplitudes in the decay J/ψ → ϕη
The first direct measurement of the relative phase between the strong and electromagnetic amplitudes for a J/ψ decaying into a vector-pseudoscalar final state is performed using 26 energy points of e + e − annihilation data between 3.00 GeV and 3.12 GeV. The data sets were collected by the BESIII detector with a total integrated luminosity of 452 pb −1 . By investigating the interference pattern in the cross section lineshape of e + e − → ϕη, the relative phase between the strong and electromagnetic amplitudes of J/ψ decay is determined to be within [133°, 228°] at 68% confidence level.
QCD↗
Measurement of the Born cross section for 𝑒 + 𝑒 − → 𝜂ℎ 𝑐 at center-of-mass energies between 4.1 and 4.6 GeV
We measure the Born cross section for the reaction 𝑒 + 𝑒 − → 𝜂ℎ 𝑐 from $\sqrt{𝑠}$ = 4.129 to 4.600 GeV using datasets collected by the BESIII detector running at the BEPCII collider. A resonant structure in the cross-section line shape near 4.200 GeV is observed with a statistical significance of 7𝜎. The parameters of this resonance are measured to be 𝑀 = 4188.8 ± 4.7 ± 8.0 MeV/𝑐 2 and Γ = 49 ± 16 ± 19 MeV, where the first uncertainties are statistical and the second systematic.
exotic mesons↗
Partial wave analysis of 𝑒 + 𝑒 − → 𝜋 + 𝜋 − 𝐽/𝜓 and cross section measurement of 𝑒 + 𝑒 − → 𝜋 ± 𝑍 𝑐 (3900) ∓ from 4.1271 to 4.3583 GeV
Based on 12.0 fb −1 of 𝑒 + 𝑒 − collision data samples collected by the BESIII detector at center-of-mass energies from 4.1271 to 4.3583 GeV, a partial wave analysis is performed for the process 𝑒 + 𝑒 − → 𝜋 + 𝜋 − 𝐽/𝜓. The cross sections for the subprocesses 𝑒 + 𝑒 − → 𝜋 + 𝑍 𝑐 (3900) − + c.c. → 𝜋 + 𝜋 − 𝐽/𝜓, 𝑓 0 (980)(→ 𝜋 + 𝜋 − )𝐽/𝜓, and (𝜋 + 𝜋 − ) S−wave 𝐽/𝜓 are measured for the first time. The mass and width of the 𝑍 𝑐 (3900) ± are determined to be 3884.6 ± 0.7 ± 3.3 MeV/𝑐 2 and 37.2 ± 1.3 ± 6.6 MeV, respectively. The first errors are statistical and the second systematic. The final state (𝜋 + 𝜋 − ) S−wave 𝐽/𝜓 dominates the process 𝑒 + 𝑒 − → 𝜋 + 𝜋 − 𝐽/𝜓. By analyzing the cross sections of 𝜋 ± 𝑍 𝑐 (3900) ∓ and 𝑓 0 (980)𝐽/𝜓, 𝑌(4220) has been observed. Its mass and width are determined to be 4225.7 ± 4.1 ± 3.4 MeV/𝑐 2 and 57.5 ± 9.4 ± 12.1 MeV, respectively.
lepton colliders↗
Search for the isospin-violating decays 𝜒 𝑐𝐽 → $Λ\bar{Σ}^0$ + c.c. and 𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c.
Using a sample of (2712.4 ± 14.3) × 10 6 𝜓(3686) events collected with the BESIII detector, we perform a search for the isospin-violating decays 𝜒 𝑐𝐽 → $Λ\bar{Σ}^0$ + c.c.(𝐽 = 0,1,2) and 𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c. No significant signal for 𝜒 𝑐𝐽 or 𝜂 𝑐 is observed in the $Λ\bar{Σ}^0$ invariant mass distribution. The upper limits on the branching fractions at the 90% confidence level are set to be ℬ(𝜒 𝑐0 → $Λ\bar{Σ}^0$ + c.c.) < 1.5 × 10 −6 , ℬ(𝜒 𝑐1 → $Λ\bar{Σ}^0$ + c.c.) < 1.6 × 10 −6 , ℬ(𝜒 𝑐2 → $Λ\bar{Σ}^0$ + c.c.) < 1.7 × 10 −6 , and ℬ(𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c.) < 6.2 × 10 −5 for the first time.
Ablikim, M. [Institute of High Energy Physics] (OR↗
Performance of laser Doppler velocimeter with polydisperse seed particles in high speed flows
The flowfield behind an oblique shock wave, where the LDV measured velocities are seed particle size dependent, was used to investigate the effects of LDV system parameters on the range of detectable polydisperse seed particles. The parameters included frequency shifting, laser power, scattered signal amplification level, and number of required fringe crossings. The results showed that with polydisperse seed particles ranging from 0.1 to 4.0 microns available in the flow, the average diameter of the detected particles could change from 0.2 to 3.0 microns by changing different LDV system parameters. The effects of this shift in the range of detectable particles on the frequency response of LDV was discussed.
Samimy, M.↗
Performance of laser Doppler velocimeter with polydisperse seed particles in high-speed flows
The flowfield behind an oblique shock wave, where the LDV measured velocities are seed-particle-size dependent, was used to investigate the effects of LDV system parameters on the range of detectable polydisperse seed particles. The parameters included frequency shifting, laser power, scattered signal amplification level, and number of required fringe crossings. The results showed that with polydisperse seed particles ranging from 0.1 to 4.0 microns available in the flow, the average diameter of the detected particles could change from 0.2 to 3.0 microns by changing different LDV system parameters. The effects of this shift in the range of detectable particles on the frequency response of LDV are discussed.
Samimy, M.↗
First JSNS 2 measurement of the electron neutrino flux using the 12 C(𝜈 𝑒 ,𝑒 − ) 12 N g.s. reaction
JSNS2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment searching for sterile neutrinos through the observation of ν¯μ→ν¯e appearance oscillations, using neutrinos produced by muon decay-at-rest. A key aspect of the experiment involves accurately understanding the neutrino flux and the quantities of pions and muons, which are progenitors of (anti)neutrinos, given that their production rates have yet to be measured. We present the first electron-neutrino flux measurement using C12(νe,e−)12Ng.s. reaction in JSNS2, yielding a flux of (6.7±1.6(stat)±1.7(syst))×10−9 cm−2 proton−1 at the JSNS2 detector location, located at 24 meters distance from the mercury target. This flux measurement is consistent with predictions from simulations based on hadron models.
Particle decays↗
Ultraheavy diquark decaying into vectorlike quarks at the LHC
We explore the discovery potential of ultraheavy (7–8.5 TeV) diquark scalars (𝑆 𝑢𝑢 ) produced in the collision of two up quarks at the LHC. Assuming that the diquark scalar decays into two vectorlike quarks of mass around 2 TeV, each of them decaying into a 𝑊 + boson and a 𝑏 quark, we focus on the fully hadronic final state. We present a signal-from-background separation study based on a discriminator built with machine learning techniques. For this six-jet final state and a luminosity of 3000 fb −1 , we estimate that a diquark scalar of mass near 8 TeV may be discovered or ruled out even when its coupling to up quarks is as low as 0.2.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Monophotons at neutrino experiments from neutrino polarizability
Nontrivial electromagnetic properties of neutrinos are an avenue to physics beyond the Standard Model (SM). To this end, we investigate the power of monophoton signals at neutrino experiments to probe a higher-dimensional operator connecting neutrinos to SM photons dubbed, neutrino polarizability. A simplified scenario giving rise to this operator involves a new pseudoscalar that couples to both neutrinos and photons, with clear implications for axionlike particle (ALP) and Majoron physics. By analyzing the photon energy spectrum and angular distributions, we find that NOMAD and MiniBooNE currently set the most stringent limits, while short baseline near detector and the DUNE near detector will soon provide significantly improved constraints.
Particle detection signatures↗
Particles from comet Kohoutek detected by the micrometeoroid experiment on HEOS 2
HEOS B measurements on particles ejected from comet Kohoutek reflect average particle rate as a function of particle speed and mass in relation to random distribution with known speed from the interplanetary region. The micrometeoroid experiment detector onboard the satellite passed through the orbital plane of the comet and encountered ejected particles for approximately two months.
Hoffmann, H. J.↗
Plasma-Based Detector of Outer-Space Dust Particles
A report presents a concept for an instrument to be flown in outer space, where it would detect dust particles - especially those associated with comets. The instrument would include a flat plate that would intercept the dust particles. The anticipated spacecraft/dust-particle relative speeds are so high that the impingement of a dust particle on the plate would generate a plasma cloud. Simple electric dipole sensors located equidistantly along the circumference of the plate would detect the dust particle indirectly by detecting the plasma cloud. The location of the dust hit could be estimated from the timing of the detection pulses of the different dipoles. The mass and composition of the dust particle could be estimated from the shapes and durations of the pulses from the dipoles. In comparison with other instruments for detecting hypervelocity dust particles, the proposed instrument offers advantages of robustness, large collection area, and simplicity.
Tsurutani, Bruce↗
The Auroral Particles experiment
An instrument for the detection of particles in the energy range of 0.1 ev to 80 Kev was designed, built, tested, calibrated, and flown onboard the spacecraft ATS-6. Data from this instrument generated the following research: intensive studies of the plasma in the vicinity of the spacecraft; global variations of plasmas; correlative studies using either other spacecraft or ground based measurements; and studies of spacecraft interactions with ambient plasmas including charging, local electric fields due to differential charging, and active control of spacecraft potential. Results from this research are presented.
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