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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 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Measurement of Inclusive Charged-Current $\barν_μ$ Scattering on C, CH, Fe, and Pb at $\langle E_{\barν}\rangle \sim$ 6 GeV with MINERvA

We report MINERvA's first measurement of inclusive charged-current $\barν_μ$ cross sections on carbon, hydrocarbon, iron, and lead, and their ratios to the cross section on hydrocarbon, as functions of the antimuon transverse momentum, $p_{\mathrm{T}}$. Using a wide-band $\barν_μ$ beam with mean energy $\sim 6~\text{GeV}$, these measurements probe all interaction modes, including the transition from resonance production to deep-inelastic scattering. The total uncertainties are typically $5-10\%$ for the absolute cross sections and $2-5\%$ for the ratios. Comparisons with multiple neutrino interaction models reveal significant discrepancies in the $p_{\mathrm{T}}$ dependence, particularly for heavier nuclei. The disagreements are most pronounced at low $p_{\mathrm{T}}$ but extend across the full $p_{\mathrm{T}}$ range, indicating missing or mis-modelled nuclear effects.

Klustová, A. [Imperial Coll., London] (ORCID:00000↗
DOE OSTI2026

First evaluation of the tracking performance of the ARCADIA Fully Depleted MAPS with 120 GeV proton beam

This work presents test beam characterization of the ARCADIA Main Demonstrator 3, a 200 $μ$m thick Fully Depleted MAPS developed using a custom LFoundry 110 nm CIS process on a high-resistivity substrate. Measurements using a 120 GeV proton beam demonstrate a detection efficiency exceeding 99% and a spatial resolution down to 3.8 $μ$m. The study evaluates cluster size, spatial resolution, and efficiency as a function of the threshold, front-end currents, and backside bias voltage.

Rignanese, M. [Padua U.; INFN, Padua]↗
DOE OSTI2011

Dependence of elliptic flow on participant nucleon number in Au + Au collisions at {radical}(s{sub NN})=200 GeV

Elliptic flows of charged particles produced in nucleus-nucleus collisions at high energy are studied in the framework of a multisource ideal-gas model. The participant nucleon number at a fixed impact parameter is calculated by a geometrical picture of the participant-spectator model. Then, the dependence of elliptic flow on participant nucleon number is obtained in the combined framework of the two models. Our calculated results are approximately in agreement with the experimental data of the PHENIX Collaboration.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Unified description of nuclear stopping in central heavy-ion collisions from 10A MeV to 1.2A GeV

A detailed analysis of the wide excitation function of nuclear stopping has been conducted within a transport model, isospin-dependent quantum molecular dynamics model, and an overall good agreement with the INDRA and FOPI Collaborations' experimental data has been achieved. It is found that the mean value of isotropy in central heavy-ion collision (HIC) reaches a minimum near-Fermi energy and approaches a maximum at around 300-400A MeV. This suggests that, in statistical average, the equilibration is far from being reached, even in central HIC especially near Fermi energy. A hierarchy in the stopping of fragments, which favors heavy fragments to penetrate, provides a robust restriction on the global trend of nuclear stopping and could serve as a probe for nuclear equations of state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Instanton effects on the twist-three light-cone distribution amplitudes of pion and light scalar mesons above 1 GeV

By use of a single-instanton approximation the twist-three light-cone distribution amplitudes of the pion as well as the p-wave mesons, i.e., f{sub 0}(1370), K{sub 0}*(1430), and a{sub 0}(1450), are investigated within the framework of QCD moment sum rules with the inclusion of instanton effects based on the valence quark model. The results show that there is much change on light-cone distribution amplitudes due to the isospin- and chirality-dependent instanton contribution compared with the instanton-free ones. We find that the instanton-involved twist-three light-cone distribution amplitudes are non-positive-definite within some range of the momentum fraction and that there are rapid changes at two ends of the momentum fraction. To guarantee the convergence of moments using the method in this work, a low instanton density should be adopted; for instance, n{sub c}=(1/2) fm{sup -4}. Possible ingredients which might have an impact on the results are briefly discussed. These light-cone distribution amplitudes may be helpful to analyze exclusive heavy-flavored processes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

PHENIX Measurement of Parity-Violating Single Spin Asymmetry in W Production in p+p Collisions at 500 GeV

The flavor-separated polarized parton distribution functions for light quarks and anti-quarks in the proton can be studied in the production of W bosons in p+p collisions. The Ws are produced in processes like u+d-bar{yields}W{sup +} and u-bar+d{yields}W{sup -} and we observe the lepton (an electron or muon) from the decay channel W{sup {+-}}{yields}l{sup {+-}}{nu}. The electron energy spectrum from W decays measured with an integrated luminosity of approximately 10 pb{sup -1} will be shown, with a measurement of the electron single spin asymmetry in central rapidity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2012

Muon g - 2 anomaly and 125 GeV Higgs: Extra vector-like quark and LHC prospects

The ATLAS and CMS collaborations recently reported indication of a Higgs boson around 125GeV. If we add extra vector-like quarks to the MSSM, such a relatively heavy Higgs can be naturally realized in the GMSB framework, simultaneously explaining the muon g - 2 anomaly. I will discuss LHC prospect of this attractive model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Toward construction of the unified lepton-nucleus interaction model from a few hundred MeV to GeV region

Next generation neutrino oscillation experiments will need a quantitative understanding of neutrino-nucleus interaction far better than ever. Kinematics covered by the relevant neutrino-nucleus interaction spans wide region, from the quasi-elastic, through the resonance region, to the deeply inelastic scattering region. The neutrino-nucleus interaction in each region has quite different characteristics. Obviously, it is essential to combine different expertise to construct a unified model that covers all the kinematical region of the neutrino-nucleus interaction. Recently, several experimentalists and theorists got together to form a collaboration to tackle this problem. In this contribution, we report the collaboration’s recent activity and a goal in near future.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

RADIATION MECHANISMS AND PHYSICAL PROPERTIES OF GeV-TeV BL Lac OBJECTS

BL Lac objects are the best candidates to study the jet properties since their spectral energy distributions (SEDs) are less contaminated by the emission from the accretion disk and external Compton processes. We compile the broadband SEDs observed with Fermi/LAT and other instruments from literature for 24 TeV BL Lac objects. Two SEDs, which are identified as a low or high state according to its flux density at 1 TeV, are available for each of 10 objects. These SEDs can be explained well with the synchrotron+synchrotron-self-Compton model. We constrain the magnetic field strength (B) and the Doppler factor ({delta}) of the radiation region by incorporating the {chi}{sup 2}-minimization technique and the {gamma}-ray transparency condition. Twenty-four out of the 34 SEDs can constrain B and {delta} in the 1{sigma} significance level, and others only present the limits for both B and {delta}. The typical values of B and {delta} are 0.1-0.6 G and 10-35, respectively. The derived values of {gamma}{sub b} are significantly different among sources and even among the low and high states of a given source. Prominent flux variations with a clear spectral shift are observed, and a tentative correlation between the ratio of the flux density at 1 TeV and the ratio of {gamma}{sub b} in the low and high states is presented, likely indicating that the relativistic shocks for the electron acceleration may be responsible for the flux variations and the spectral shift. A weak anti-correlation between the jet power and the mass of the central black hole is observed, i.e., P{sub jet}{proportional_to}M{sup -1}{sub BH}, which disfavors the scenario of a pure accretion-driven jet. Implications for the blazar sequence and the intergalactic magnetic field from our results are also briefly discussed.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

'Self-absorbed' GeV light curves of gamma-ray burst afterglows

We investigate the effect that the absorption of high-energy (above 100 MeV) photons produced in gamma-ray burst afterglow shocks has on the light curves and spectra of Fermi Large Area Telescope (LAT) afterglows. Afterglows produced by the interaction of a relativistic outflow with a wind-like medium peak when the blast wave deceleration sets in, and the afterglow spectrum could be hardening before that peak, as the optical thickness to pair formation is decreasing. In contrast, in afterglows produced in the interaction with a homogeneous medium, the optical thickness to pair formation should increase and yield a light curve peak when it reaches unity, followed by a fast light curve decay, accompanied by spectral softening. If energy is injected in the blast wave, then the accelerated increase of the optical thickness yields a convex afterglow light curve. Other features, such as a double-peak light curve or a broad hump, can arise from the evolution of the optical thickness to photon-photon absorption. Fast decays and convex light curves are seen in a few LAT afterglows, but the expected spectral softening is rarely seen in (and difficult to measure with) LAT observations. Furthermore, for the effects of photon-photon attenuation to shape the high-energy afterglow light curve without attenuating it too much, the ejecta initial Lorentz factor must be in a relatively narrow range (50-200), which reduces the chance of observing those effects.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Discovery of GeV emission from the direction of the luminous infrared galaxy NGC 2146

Recent detections of high-energy gamma-ray emission from starburst galaxies M82 and NGC 253 suggest that starburst galaxies are huge reservoirs of cosmic rays and these cosmic rays convert a significant fraction of their energy into gamma-rays by colliding with the dense interstellar medium. In this paper, we report the search for high-energy gamma-ray emission from several nearby star-forming and starburst galaxies using the 68 month data obtained with the Fermi Large Area Telescope. We found a ∼5.5σ detection of gamma-ray emission above 200 MeV from a source spatially coincident with the location of the luminous infrared galaxy NGC 2146. Also taking into account the temporal and spectral properties of the gamma-ray emission, we suggest that the gamma-ray source is likely to be the counterpart of NGC 2146. The gamma-ray luminosity suggests that cosmic rays in NGC 2146 convert most of their energy into secondary pions, so NGC 2146 is a 'proton calorimeter'. It is also found that NGC 2146 obeys the quasi-linear scaling relation between gamma-ray luminosity and total infrared luminosity for star-forming galaxies, strengthening the connection between massive star formation and gamma-ray emission of star-forming galaxies. Possible TeV emission from NGC 2146 is predicted and the implications for high-energy neutrino emission from starburst galaxies are discussed.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

The 130 GeV gamma-ray line and Sommerfeld enhancements

Recently, possible indications of line spectral features in the Fermi-LAT photon spectrum towards the galactic center have been reported. If the distinct line features arise from dark matter (DM) annihilation into γX(X = γ,Z{sup 0} or h{sup 0}), the corresponding annihilation cross-section is unnaturally large for typical loop-induced radiative processes. On the other hand, it is still too small to be responsible for the observed DM relic density. We show that the mechanism of Sommerfeld enhancement with scalar force-carrier can provide a simple solution to these puzzles. The possibly large Sommerfeld enhancement of the cross-section for s-wave DM annihilation can significantly reduce the required effective couplings between DM and charged particles in typical loop diagrams. The DM particles necessarily annihilate into scalar force-carriers through tree-level p-wave process, which can dominate the total DM annihilation cross-section at freeze out, resulting in the correct thermal relic density, but has subdominant contributions to the DM annihilation today due to velocity suppression. We perform detailed analysis on the effects of p-wave Sommerfeld enhancement on freeze out. The results show that with the constraints from the thermal relic density, the required effective couplings can be reduced by an order of magnitude.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically reduced, and the point-source sensitivity improved, by selecting a narrow time window around possible neutrino production periods. Blazars, being radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the very high-energy cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions with the surrounding medium. Moreover, blazars generally show high time variability in their light curves at different wavelengths and on various time scales. This paper presents a time-dependent analysis applied to a selection of flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012. The results are compatible with fluctuations of the background. Upper limits on the neutrino fluence have been produced and compared to the measured gamma-ray spectral energy distribution.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2011

Cross sections for monitor reactions {sup 27}Al((p, x){sup 24}Na, {sup 27}Al(p, x){sup 22}Na, and {sup 27}Al(p, x){sup 7}Be at proton energies in the range 0.04-2.6 GeV

The cross sections for the monitor reactions {sup 27}Al(p, x){sup 24}Na, {sup 27}Al(p, x){sup 22}Na, and {sup 27}Al(p, x){sup 7}Be at 12 proton energies, 2605, 1598, 1199, 799, 600, 400, 249, 147.6, 97.2, 66.0, 44.6, and 40.8 MeV, have been determined with 72 Multiplication-Sign 72-mm square and 10.5-mm-diameter round aluminum foils. The rates of the reactions of the production of {sup 24}Na, {sup 22}Na, and {sup 7}Be in the foils in each irradiation run have been determined by {gamma} spectrometry, whereas the number of protons transmitted through these foils has been determined using calibrated fast current transformers. The cross sections have been determined as the ratios of the corresponding reaction to the average proton fluence.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Long-term Study of the Light Curve of PKS 1510-089 in GeV Energies

We have analyzed data from the flat-spectrum radio quasar PKS 1510-089 collected over a period of eight years from 2008 August to 2016 December with the Fermi -LAT. We have identified several flares of this highly variable source, studied their temporal and spectral properties in detail, and compared with previous works on flares of PKS 1510-089. Five major flares and a few subflares or substructures have been identified in our study. The fastest variability time is found to be 1.30 ± 0.18 hr between MJD 55852.063 and 55852.188, where we estimate the minimum size of the emission region to be 4.85 × 10{sup 15} cm. In most of the flares, the spectral energy distributions are better fitted with a log-parabolic distribution compared to a simple power law or a power law with exponential cutoffs. This has strong physics implications regarding the nature of the high-energy gamma-ray emission region.

79 ASTRONOMY AND ASTROPHYSICS↗