Search NASA⌕ Search

SEARCH · Search NASA

Results for “Collection 6”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Octahedral Distortion and Excitonic Behavior of Cs 3 Bi 2 Br 9 Halide Perovskite at Low Temperature

The metal halide ionic octahedron, represented as [MX 6 ] $n$- (M = metal cation, X = halide anion), serves as the basic structural unit in halide perovskites and plays a crucial role in determining their optoelectronic and chemical properties. Thus, it is possible to correlate the responses of metal halide perovskites to various environmental stimuli with the dynamic behaviors of the [MX 6 ] $n$- octahedra. In this study, with the temperature-dependent single-crystal X ray diffraction (SCXRD) measurements on Cs 3 Bi 2 Br 9 2D halide perovskites, we can identify two classes of distortions through the lowering of temperature: intraoctahedral distortion, which is the off-centering of Bi 3+ cation within a [BiBr 6 ] 3– octahedron due to the Bi 3+ 6s 2 lone pair electrons, and interoctahedral distortion, which is the collective misalignments among the [BiBr 6 ] 3– building blocks. Free exciton (FE) and self-trapped exciton (STE) models are used to study the relationship between the distortion of octahedra in Cs 3 Bi 2 Br 9 and the corresponding changes in its optoelectronic properties, which transform from dominating blue emission above 100 K to red emission at 4 K. In conclusion, this work provides new insights into the excitonic behaviors of perovskites and suggests a possibility that we can design and rationalize the optical properties of halide perovskites by regulating the environmental stimuli based on the knowledge of behaviors of the individual [MX 6 ] $n$- building blocks.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Study of the processes $χ_{cJ}$ → $Ξ^–\overline{Ξ}^+$ and $Ξ^0 \overline{Ξ} ^0$

Using 448.1 x 10 6 $\psi$(3686) decays collected with the BESIII detector at the BEPCII $e^+e^-$ storage rings, the branching fractions and angular distributions of the decays $χ_{cJ}$ → $Ξ^–\overline{Ξ}^+$ and $Ξ^0 \overline{Ξ} ^0$ (J = 0, 1, 2) are measured based on a partial-reconstruction technique. The decays $χ_{c1}$ → $Ξ^0 \overline{Ξ} ^0$ and $χ_{c2}$ → $Ξ^0 \overline{Ξ} ^0$ are observed for the first time with statistical significances of 7σ and 15σ, respectively. The results of this analysis are in good agreement with previous measurements and have significantly improved precision.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Search for lepton-flavor-violating tau decays to ℓα at Belle

We report a search for the lepton-flavor-violating decays τ ± → ℓ ± α (ℓ = e, μ), where α is an undetected spin-0 particle, such as an axion-like particle using 736 × 10 6 tau lepton pairs collected by the Belle detector at the KEKB asymmetric-energy e + e − collider. We find no evidence of signal and obtain the most stringent upper limits on the branching fractions at 95% confidence level: $\mathcal{B}$ (τ ± → e ± α) < (0.4–6.4) × 10 −4 and $\mathcal{B}$ (τ ± → μ ± α) < (0.2–3.5) × 10 −4 at 95% confidence level for an α mass in the range 0.0 ≤ m α ≤ 1.6 GeV/c 2 .

tau physics↗
DOE OSTI2021

Measurement of branching fractions of $J/\psi$ and $\psi$(3686) decays to $\Sigma^+$< and $\overline\Sigma^-$

Using 1310.6 x 10 6 J/ψ and 448.1 x 10 6 ψ(3686) events collected with the BESIII detector, the branching fractions of J/ψ decays to $Σ^+\overline{Σ}^-$ is measured to be (10.61 ± 0.04 ± 0.36) x 10 -4 , which is significantly more precise than the current world average. The branching fractions of ψ(3686) decays to $Σ^+\overline{Σ}^-$ is measured to be (2.52 ± 0.04 ± 0.09) x 10 -4 , which is consistent with the previous measurements. In addition, the ratio of $\mathcal{B}$(ψ(3686) → $Σ^+\overline{Σ}^-$)/$\mathcal{B}$(J/ψ → $Σ^+\overline{Σ}^-$) is determined to be (23.8 ± 1.1)% which violates the “12% rule”.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Observation of the decay ψ (3686) → $ {\Sigma}^{-}{\overline{\Sigma}}^{+} $ and measurement of its angular distribution

Using (448.1 ± 2.9) × 10 6 ψ(3686) events collected with the BESIII detector at the BEPCII collider, the decay ψ(3686) → Σ - $\overline{Σ}$ + is observed for the first time with a branching fraction of (2.82 ± 0.04 stat. ± 0.08 syst. ) × 10 -4 , and the angular parameter α Σ- is measured to be 0.96 ± 0.09 stat. ± 0.03 syst. .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

The POEMMA (Probe of Extreme Multi-Messenger Astrophysics) observatory

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to accurately observe ultra-high-energy cosmic rays (UHECRs) and cosmic neutrinos from space with sensitivity over the full celestial sky. POEMMA will observe the air fluorescence produced by extensive air showers (EASs) from UHECRs and potentially UHE neutrinos above 20 EeV. Additionally, POEMMA has the ability to observe the Cherenkov signal from upward-moving EASs induced by Earth-interacting tau neutrinos above 20 PeV. The POEMMA spacecraft are designed to quickly re-orientate to follow up transient neutrino sources and obtain currently unparalleled neutrino flux sensitivity. Developed as a NASA Astrophysics Probe-class mission, POEMMA consists of two identical satellites flying in loose formation in 525 km altitude orbits. Each POEMMA instrument incorporates a wide field-of-view (45°) Schmidt telescope with an optical collecting area of over 6 m 2 . The hybrid focal surface of each telescope includes a fast (1 μs) near-ultraviolet camera for EAS fluorescence observations and an ultrafast (10 ns) optical camera for Cherenkov EAS observations. In a 5-year mission, POEMMA will provide measurements that open new multi-messenger windows onto the most energetic events in the universe, enabling the study of new astrophysics and particle physics at these extreme energies.

Astronomy & Astrophysics↗
DOE OSTI2022

Search for the weak decay ψ (3686) → $Λ^{+}_{c}$ $\overline{Σ}$ - + c.c. *

Using (448.1 ± 2.9) x 10 6 ψ (3686) events collected with the BESIII detector, we perform the first search for the weak baryonic decay ψ (3686) → $Λ^{+}_{c}$ $\overline{Σ}$ - + c.c. . The analysis procedure is optimized using a blinded method. No significant signal is observed, and the upper limit on the branching fraction ($\mathcal{B}$) of ψ (3686) → $Λ^{+}_{c}$ $\overline{Σ}$ - + c.c. is set as 1.4 x 10 -5 at the 90% confidence level.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Analytic Chromaticity Formulas for the Muon g -2 experiment at fermilab

The Muon g-2 Experiment (E989) at Fermilab measured the muon anomalous magnetic moment aμ with unprecedented precision of 127 ppb using a storage ring. The experiment pushed the limits in terms of accuracy and systematic errors. Achieving the 78-ppb total systematic uncertainty required precise beam dynamics modeling and corrections for effects on the measured muon precession frequency. Here, we derived the first analytic aberration formulas up to the second order for the muon g-2 storage ring’s combined-function electrostatic quadrupoles (superimposed magnetic dipole and electric quadrupole fields) using an order-by-order perturbation method. From these, we obtained the exact chromaticity formulas for three ring models of different granularity and validated them against numerical calculations using COSY INFINITY, achieving analytic-numerical agreement to ⁠$\mathscr{O}(10^{-10})$. This work resolved discrepancies between previous approximate derivations and provided essential beam dynamics results for Runs 4-6 analyses. We also calculated nonlinear chromaticities up to ninth order. The experiment completed its final Run 6 in July 2023, collecting 21 times more data than the previous muon g-2 experiment at Brookhaven National Laboratory, with the final result announced in June 2025.

aberrations↗
DOE OSTI2021

Use of nucleic acid amplification testing for rapid detection of Mycobacterium tuberculosis complex among U.S. tuberculosis patients from 2011–2017

Background: Nucleic acid amplification (NAA) tests rapidly detect Mycobacterium tuberculosis complex directly from clinical specimens, providing valuable results for those evaluated for tuberculosis. Methods: We analyzed characteristics of cases with NAA testing performed, compared cases with positive and negative NAA test results, and calculated turnaround time and time to treatment for all verified cases reported to the National Tuberculosis Surveillance System in the United States during 2011–2017. Results: Among 67082 verified tuberculosis cases with NAA testing information, 30820 (45.9%) were reported as not having an NAA test performed; the proportion without NAA testing declined annually, from 60.5% in 2011 to 33.6% in 2017. Of 67082 verified cases, 27912 (41.6%) had positive, 8215 (12.2%) had negative, and 135 (0.2%) had indeterminate NAA test results. Among the 33937 cases with an acid-fast bacilli (AFB) smear-positive result, 24093 (70.9%) had an NAA test performed; 11490 of the 30244 (38.0%) with an AFB smear-negative result had an NAA test performed. Although sputum was the most common specimen type tested, 79.8% (7023/8804) of nonsputum specimen types had a positive NAA test result. Overall, 63.7% of cases with laboratory testing had NAA test results reported <6 days following specimen collection; for 13891 cases not yet on treatment, median time to treatment after the laboratory report date was 2 days. Conclusions: Our analyses demonstrate increased NAA test utilization between 2011 and 2017. However, a large proportion of cases did not have an NAA test performed, reflecting challenges in broader uptake, suggesting an opportunity to expand use of this diagnostic methodology.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Observation of the decay J / ψ → e + e − η ( 1405 ) with η ( 1405 ) → π 0 f 0 ( 980 )

Using a data sample of ( 10087 ± 44 ) × 10 6 J / ψ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process J / ψ → e + e − η ( 1405 ) is observed via the decay η ( 1405 ) → π 0 f 0 ( 980 ) , f 0 ( 980 ) → π + π − , with a significance of about 9.8 σ . The branching fraction of this decay is measured to be B ( J / ψ → e + e − η ( 1405 ) → e + e − π 0 f 0 ( 980 ) → e + e − π 0 π + π − ) = ( 2.04 ± 0.20 ( stat ) ± 0.08 ( syst ) ) × 10 − 7 . The branching fraction ratio B ( J / ψ → e + e − η ( 1405 ) ) / B ( J / ψ → γ η ( 1405 ) ) is determined to be ( 1.36 ± 0.17 ( stat ) ± 0.06 ( syst ) ) × 10 − 2 . Furthermore, an e + e − invariant mass dependent transition form factor of J / ψ → e + e − η ( 1405 ) is presented for the first time. The obtained result provides input for different theoretical models and is valuable for the improved understanding the intrinsic structure of the η ( 1405 ) meson. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Study of excited Ξ states in ψ ( 3686 ) → K − Λ Ξ ¯ + + c . c .

Based on a sample of ( 448.1 ± 2.9 ) × 10 6 ψ ( 3686 ) events collected with the BESIII detector at BEPCII, the decays of ψ ( 3686 ) → K − Λ Ξ ¯ + + c . c . with Ξ ¯ + → Λ ¯ π + , Λ ¯ → p ¯ π + are studied. We investigate the two excited resonances, Ξ ( 1690 ) − and Ξ ( 1820 ) − , which are each observed with large significance ( ≫ 10 σ ) in the K − Λ invariant mass distributions. A partial wave analysis is performed, and the spin-parities of Ξ ( 1690 ) − and Ξ ( 1820 ) − are measured to be 1 2 − and 3 2 − , respectively. The masses, widths, and product branching fractions of Ξ ( 1690 ) − and Ξ ( 1820 ) − are also measured. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Study of h c → 3 ( π + π − ) π 0 , h c → 2 ( π + π − ) ω , h c → 2 ( π + π − ) π 0 η , h c → 2 ( π + π − ) η , and h c → p p ¯

Based on ( 2712.4 ± 14.1 ) × 10 6 ψ ( 3686 ) events collected with the BESIII detector, we study the decays h c → 3 ( π + π − ) π 0 , h c → 2 ( π + π − ) ω , h c → 2 ( π + π − ) π 0 η , h c → 2 ( π + π − ) η , and h c → p p ¯ via ψ ( 3686 ) → π 0 h c . The decay channel h c → 3 ( π + π − ) π 0 is observed for the first time, and its branching fraction is determined to be ( 9.28 ± 1.14 ± 0.77 ) × 10 − 3 , where the first uncertainty is statistical and the second is systematic. In addition, first evidence is found for the modes h c → 2 ( π + π − ) π 0 η and h c → 2 ( π + π − ) ω with significances of 4.8 σ and 4.7 σ , and their branching fractions are determined to be ( 7.55 ± 1.51 ± 0.77 ) × 10 − 3 and ( 4.00 ± 0.86 ± 0.35 ) × 10 − 3 , respectively. No significant signals of h c → 2 ( π + π − ) η and h c → p p ¯ are observed, and the upper limits of the branching fractions of these decays are determined to be < 6.19 × 10 − 4 and < 4.40 × 10 − 5 at the 90% confidence level, respectively. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Measurement of C P asymmetries in B 0 → K S 0 K S 0 K S 0 decays at Belle II

We report a measurement of decay-time-dependent charge-parity ( C P ) asymmetries in B 0 → K S 0 K S 0 K S 0 decays. We use 387 × 10 6 B B ¯ pairs collected at the ϒ ( 4 S ) resonance with the Belle II detector at the SuperKEKB asymmetric-energy electron-positron collider. We reconstruct 220 signal events and extract the C P -violating parameters S and C from a fit to the distribution of the decay-time difference between the two B mesons. The resulting confidence region is consistent with previous measurements in B 0 → K S 0 K S 0 K S 0 and B 0 → ( c c ¯ ) K 0 decays and with predictions based on the standard model. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Search for X ( 1870 ) via the decay J / ψ → ω K + K − η

Using a sample of ( 10087 ± 44 ) × 10 6 J / ψ events collected by the BESIII detector at the BEPCII collider, we search for the decay X ( 1870 ) → K + K − η via the J / ψ → ω K + K − η process for the first time. No significant X ( 1870 ) signal is observed. The upper limit on the branching fraction of the decay J / ψ → ω X ( 1870 ) → ω K + K − η is determined to be 9.55 × 10 − 7 at the 90% confidence level. In addition, the branching faction B ( J / ψ → ω K + K − η ) is measured to be ( 3.33 ± 0.02 ( stat ) ± 0.12 ( syst ) ) × 10 − 4 . Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Search for h c → π + π − J / ψ via ψ ( 3686 ) → π 0 h c

Using ( 2712.4 ± 14.3 ) × 10 6 ψ ( 3686 ) events collected with the BESIII detector operating at the BEPCII collider, we search for the hadronic transition h c → π + π − J / ψ via ψ ( 3686 ) → π 0 h c . No significant signal is observed. We set the most stringent upper limits to date on the branching fractions B ( ψ ( 3686 ) → π 0 h c ) × B ( h c → π + π − J / ψ ) and B ( h c → π + π − J / ψ ) at the 90% confidence level, which are determined to be 6.7 × 10 − 7 and 9.4 × 10 − 4 , respectively. Published by the American Physical Society 2024

Ablikim, M.↗
DOE OSTI2025

Observation of η c ( 1 S , 2 S ) and χ c J decays to 2 ( π + π − ) η via ψ ( 3686 ) radiative transitions

Based on ( 2712.4 ± 14.1 ) × 10 6 ψ ( 3686 ) decays collected with the BESIII detector, we have observed, for the first time, the hadronic decays of S- and P-wave charmonium states into 2 ( π + π − ) η via radiative transitions from ψ ( 3686 ) . The branching fraction of the decay η c ( 1 S ) → 2 ( π + π − ) η has a significant dependence on the interference pattern between η c ( 1 S ) and non- η c ( 1 S ) processes. We measure it in both the destructive and constructive interference scenarios for the first time. The mass and width of the η c ( 1 S ) are measured to be M = ( 2984.14 ± 0.13 ± 0.38 ) MeV / c 2 and Γ = ( 28.82 ± 0.11 ± 0.82 ) MeV , respectively. Clear signals for the decays of the χ c J ( J = 0 , 1 , 2 ) and the η c ( 2 S ) to 2 ( π + π − ) η are also observed for the first time, and the corresponding branching fractions are measured. The ratio of the branching fractions between the η c ( 2 S ) and η c ( 1 S ) decays is significantly lower than the theoretical prediction, which might suggest different dynamics in their decays. Published by the American Physical Society 2025

Ablikim, M.↗
DOE OSTI2025

Search for η c ( 2 S ) → p p ¯ K + K − and measurement of χ c J → p p ¯ K + K − in ψ ( 3686 ) radiative decays

A search for η c ( 2 S ) → p p ¯ K + K − , together with measurement of branching fractions of χ c J ( J = 0 , 1 , 2 ) → p p ¯ K + K − in the ψ ( 3686 ) → γ η c ( 2 S ) and the ψ ( 3686 ) → γ χ c J radiative decays, is performed with ( 2712.4 ± 14.3 ) × 10 6 ψ ( 3686 ) events collected with the BESIII detector at the BEPCII collider. An evidence for η c ( 2 S ) → p p ¯ K + K − is found, with a significance of 3.3 σ . The product branching fraction of B [ ψ ( 3686 ) → γ η c ( 2 S ) ] · B [ η c ( 2 S ) → p p ¯ K + K − ] is determined to be ( 1.98 ± 0.4 1 stat ± 0.9 9 syst ) × 10 − 7 . The product branching fractions of B [ ψ ( 3686 ) → γ χ c J ] · B [ χ c J → p p ¯ K + K − ] are measured to be ( 2.49 ± 0.0 3 stat ± 0.1 5 syst ) × 10 − 5 , ( 1.83 ± 0.0 2 stat ± 0.1 1 syst ) × 10 − 5 , and ( 2.43 ± 0.0 2 stat ± 0.1 5 syst ) × 10 − 5 , for J = 0 , 1, and 2, respectively. Published by the American Physical Society 2025

Ablikim, M.↗
DOE OSTI2024

Investigation of the Δ I = 1 / 2 Rule and Test of C P Symmetry through the Measurement of Decay Asymmetry Parameters in Ξ − Decays

Using ( 10 087 ± 44 ) × 10 6 J / ψ events collected with the BESIII detector, numerous Ξ − and Λ decay asymmetry parameters are simultaneously determined from the process J / ψ → Ξ − Ξ ¯ + → Λ ( p π − ) π − Λ ¯ ( n ¯ π 0 ) π + and its charge-conjugate channel. The precisions of α Λ 0 for Λ → n π 0 and α ¯ Λ 0 for Λ ¯ → n ¯ π 0 compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ → n π 0 to that of Λ → p π − , ⟨ α Λ 0 ⟩ / ⟨ α Λ − ⟩ , is determined to be 0.873 ± 0.01 2 − 0.010 + 0.011 , where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5 σ , which signifies the existence of the Δ I = 3 / 2 transition in Λ for the first time. Besides, we test for C P symmetry in Ξ − → Λ π − and in Λ → n π 0 with the best precision to date. Published by the American Physical Society 2024

Physics↗