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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Observation of e + e - → ηψ(2S) at center-of-mass energies from 4.236 to 4.600 GeV

Using a total of 5 25 fb -1 of e + e - collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the processe + e - → ηψ(2S) with a statistical significance of 4.9 standard deviations. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of Λ transverse polarization in e+e− collisions at $$ \sqrt{s} $$ = 3.68 − 3.71 GeV

Abstract With data samples collected with the BESIII detector at seven energy points at$$ \sqrt{s} $$ s = 3.68−3.71 GeV, corresponding to an integrated luminosity of 333 pb −1 , we present a study of the Λ transverse polarization in thee + e − →$$ \Lambda \overline{\Lambda} $$ Λ Λ ¯ reaction. The significance of polarization by combining the seven energy points is found to be 2.6σincluding the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the$$ \Lambda \overline{\Lambda} $$ Λ Λ ¯ helicity states. The modulus ratio and the relative phase of EM-psionicform factors combined with all energy points are measured to beR Ψ =$$ {0.71}_{-0.10}^{+0.10} $$ 0.71 − 0.10 + 0.10 ±0.03 and ∆Φ Ψ =$$ {23}_{-8.0}^{+8.8} $$ 23 − 8.0 + 8.8 ±1.6°, where the first uncertainties are statistical and the second systematic.

Physics↗
DOE OSTI2025

Amplitude analysis of ψ3686→γKS0KS0

Using (2712 ± 14) × 106ψ(3686) events collected with the BESIII detector, we perform the first amplitude analysis of the radiative decay ψ3686→γKS0KS0$$ \psi (3686)\to \gamma {K}_S^0{K}_S^0 $$ within the mass region MKS0KS0<2.8$$ {M}_{K_S^0{K}_S^0}<2.8 $$ GeV/c2. Employing a one-channel K-matrix approach for the description of the dynamics of the KS0KS0$$ {K}_S^0{K}_S^0 $$ system, the data sample is well described with four poles for the f0-wave and three poles for the f2-wave. The determined pole positions are consistent with those of well-established resonance states. The observed f0 and f2 states are found to be in agreement with those produced in radiative J/ψ decays. The production behaviors of f0 and f2 poles in ψ3686→γKS0KS0$$ \psi (3686)\to \gamma {K}_S^0{K}_S^0 $$ are qualified with their residues and the converted branching fractions. By comparing with J/ψ→γKS0KS0$$ J/\psi \to \gamma {K}_S^0{K}_S^0 $$ decay, the ratios Bψ3686→γf0,2BJ/ψ→γf0,2$$ \frac{\mathcal{B}\left(\psi (3686)\to \gamma {f}_{0,2}\right)}{\mathcal{B}\left(J/\psi \to \gamma {f}_{0,2}\right)} $$ are determined, which provides crucial experimental inputs on the internal structure of the f0,2 states, especially their potential mixing with glueball components.

Ablikim, M↗
DOE OSTI2021

Observation of the decays $χ$ cJ → $\mathrm{nK}^0_s\overline{Λ}$ + $c.c.$

By analyzing 4.48 x 10 8 ψ(3686) events collected with the BESIII detector, we observe the decays $χ$ cJ → $\mathrm{nK}^0_s\overline{Λ}$ + $c.c.$ (J = 0, 1, 2) for the first time, via the radiative transition ψ(3686) → $γχ_{cJ}$. The branching fractions are determined to be (6.65 ± 0.26 stat ± 0.41 syst ) x 10 -4 , (1.66 ± 0.12 stat ± 0.12 syst ) x 10 -4 , and (3.58 ± 0.16 stat ± 0.23 syst ) x 10 -4 for J = 0, 1, and 2, respectively.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
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 OSTI2023

Measurement of the branching fractions of the singly Cabibbo-suppressed decays $$ {\Lambda}_{\textrm{c}}^{+}\to \textrm{p}\eta $$ and $$ {\Lambda}_{\textrm{c}}^{+}\to \textrm{p}\omega $$

Abstract Based on 4.5 fb −1 e + e − collision data collected with BESIII detector at seven energy points between 4.600 and 4.699 GeV, the branching fractions for$$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη and$$ {\Lambda}_c^{+}\to p\omega $$ Λ c + → pω were measured by means of single-tag method. The branching fractions of$$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη and$$ {\Lambda}_c^{+}\to p\omega $$ Λ c + → pω are determined to be (1.57±0.11 stat ±0.04 syst )×10 −3 and (1.11±0.20 stat ±0.07 syst )×10 −3 , with a statistical significance of greater than 10σand 5.7σ, respectively. These results are consistent with the previous measurements by BESIII, LHCb and Belle, and the result of$$ {\Lambda}_c^{+}\to p\eta $$ Λ c + → pη is the most precise to date.

Physics↗
DOE OSTI2023

Measurement of the cross section of $$ {e}^{+}{e}^{-}\to {\Xi}^{-}{\overline{\Xi}}^{+} $$ at center-of-mass energies between 3.510 and 4.843 GeV

Abstract Usinge + e − collision data corresponding to a total integrated luminosity of 12.9 fb −1 collected with the BESIII detector at the BEPCII collider, the exclusive Born cross sections and the effective form factors of the reaction$$ {e}^{+}{e}^{-}\to {\Xi}^{-}{\overline{\Xi}}^{+} $$ e + e − → Ξ − Ξ ¯ + are measured via the single baryon-tag method at 23 center-of-mass energies between 3.510 and 4.843 GeV. Evidence for the decay$$ \psi (3770)\to {\Xi}^{-}{\overline{\Xi}}^{+} $$ ψ 3770 → Ξ − Ξ ¯ + is observed with a significance of 4.5σby analyzing the measured cross sections together with earlier BESIII results. For the other charmonium(-like) statesψ(4040),ψ(4160),Y(4230),Y(4360),ψ(4415), andY(4660), no significant signal of their decay to$$ {\Xi}^{-}{\overline{\Xi}}^{+} $$ Ξ − Ξ ¯ + is found. For these states, upper limits of the products of the branching fraction and the electronic partial width at the 90% confidence level are provided.

Physics↗
DOE OSTI2025

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↗
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 OSTI2022

Partial wave analysis of the charmed baryon hadronic decay $ {\Lambda}_c^{+} $ → Λ π +π 0

Based on e + e - collision samples corresponding to an integrated luminosity of 4.4 fb -1 collected with the BESIII detector at center-of-mass energies between 4.6 GeV and 4.7 GeV, a partial wave analysis of the charmed baryon hadronic decay ${\Lambda}_c^{+}$ → Λπ + π 0 is performed, and the decays ${\Lambda}_c^{+}$ → Λρ(770) + and ${\Lambda}_c^{+}$ → Σ(1385)π are studied for the first time. Making use of the world-average branching fraction $\mathcal{B}$ (${\Lambda}_c^{+}$ → Λπ + π 0 ), their branching fractions are determined to be $\mathcal{B}$(${\Lambda}_c^{+}$ → Λρ(770) + ) = (4.06 ± 0.30 ± 0.35 ± 0.23) x 10 -2 , $\mathcal{B}$(${\Lambda}_c^{+}$ → Σ(1385) + )π 0 ) = (5.86 ± 0.49 ± 0.52 ± 0.35) x 10 -3 , $\mathcal{B}$(${\Lambda}_c^{+}$ → Σ(1385) 0 )π + ) = (6.47 ± 0.59 ± 0.66 ± 0.38) x 10 -3 , where the first uncertainties are statistical, the second are systematic, and the third are from the uncertainties of the branching fractions $\mathcal{B}$ ${\Lambda}_c^{+}$ → Λπ + π 0 and $\mathcal{B}$(Σ(1385) → Λπ). In addition, the decay asymmetry parameters are measured to be αΛρ(770)+ = - 0.763 ± 0.053 ± 0.045, $\alpha$ Σ(1385)+π 0 = -0.917 ± 0.069 ± 0.056, and $\alpha$ Σ(1385) 0 π + = -0.789 ± 0.098 ± 0.056.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Measurement of the cross section of e + e - → ηπ + π - at center-of-mass energies from 3.872 GeV to 4.700 GeV

Using data samples with an integrated luminosity of 19 fb -1 at twenty-eight center-of-mass energies from 3.872 GeV to 4.700 GeV collected with the BESIII detector at the BEPCII electron-positron collider, the process e + e - → ηπ + π - and the intermediate process e + e - → ηρ 0 are studied for the first time. The Born cross sections are measured. No significant resonance structure is observed in the cross section lineshape.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of $$ {e}^{+}{e}^{-}\to p{K}^{-}\overline{\Lambda}+c.c. $$ cross sections between 4.009 GeV and 4.951 GeV

Abstract Usinge + e − collision datasets corresponding to a total integrated luminosity of 21.7 fb −1 collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 4.009 GeV to 4.951 GeV, the energy-dependent cross sections of$$ {e}^{+}{e}^{-}\to p{K}^{-}\overline{\Lambda}+c.c. $$ e + e − → p K − Λ ¯ + c . c . are measured for the first time. By fitting these energy-dependent cross sections, we search for the excitedψstatesψ(4160) andψ(4415), and the vector charmonium-like statesψ(4230),ψ(4360), andψ(4660). No evidence for these is observed and the upper limits on the branching fractions of these states decaying into$$ p{K}^{-}\overline{\Lambda}+c.c. $$ p K − Λ ¯ + c . c . are set at the 90% confidence level.

Physics↗
DOE OSTI2023

Studies of the decay $$ {\textrm{D}}_{\textrm{s}}^{+}\to {\textrm{K}}^{+}{\textrm{K}}^{-}{\mu}^{+}{\nu}_{\mu } $$

Abstract The$$ {D}_s^{+}\to {K}^{+}{K}^{-}{\mu}^{+}{\nu}_{\mu } $$ D s + → K + K − μ + ν μ decay is studied based on 7.33 fb −1 ofe + e − collision data collected with the BESIII detector at center-of-mass energies in the range from 4.128 to 4.226 GeV. The absolute branching fraction is measured as$$ \mathcal{B}\left({D}_s^{+}\to \phi {\mu}^{+}{\nu}_{\mu}\right)=\left(2.25\pm 0.09\pm 0.07\right)\times {10}^{-2} $$ B D s + → ϕ μ + ν μ = 2.25 ± 0.09 ± 0.07 × 10 − 2 , the most precise measurement to date. Combining with the world average of$$ \mathcal{B}\left({D}_s^{+}\to \phi {e}^{+}{\nu}_e\right) $$ B D s + → ϕ e + ν e , the ratio of the branching fractions obtained is$$ \frac{\mathcal{B}\left({D}_s^{+}\to \phi {\mu}^{+}{\nu}_{\mu}\right)}{\mathcal{B}\left({D}_s^{+}\to \phi {e}^{+}{\nu}_e\right)}=0.94\pm 0.08 $$ B D s + → ϕ μ + ν μ B D s + → ϕ e + ν e = 0.94 ± 0.08 , in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios atq 2 = 0 are extracted, finding$$ {r}_V=\frac{V(0)}{A_1(0)}=1.58\pm 0.17\pm 0.02 $$ r V = V 0 A 1 0 = 1.58 ± 0.17 ± 0.02 and$$ {r}_2=\frac{A_2(0)}{A_1(0)}=0.71\pm 0.14\pm 0.02 $$ r 2 = A 2 0 A 1 0 = 0.71 ± 0.14 ± 0.02 , where the first uncertainties are statistical and the second are systematic. No significantS-wave contribution fromf 0 (980)→ K + K − is found. The upper limit$$ \mathcal{B}\left({D}_s^{+}\to {f}_0(980){\mu}^{+}{\nu}_{\mu}\right)\cdot \mathcal{B}\left({f}_0(980)\to {K}^{+}{K}^{-}\right)<5.45\times {10}^{-4} $$ B D s + → f 0 980 μ + ν μ ⋅ B f 0 980 → K + K − < 5.45 × 10 − 4 is set at 90% credibility level.

Physics↗
DOE OSTI2022

Gamma-ray spectra analyses of molten salts in spent nuclear fuels pyroprocessing facilities for mass measurement

To evaluate radioactive tracer dilution and gamma spectroscopy as a safeguards technique for monitoring the mass of liquid salt in molten salt systems, the gamma spectroscopy data of salt samples from the pyroprocessing facilities in Idaho National Laboratory were acquired and analyzed. The primary focus is the uncertainty analysis of the gamma radioactivity of 154 Eu isotope in the molten salts. The facilities include an electrorefiner for pyroprocessing spent oxide fuels (SOF-ER) and Mark-IV ER for processing the metallic fuels from Experimental Breeder Reactor-II (EBR-II). The relative gamma radioactivity uncertainty was consistently at 3% for 137 Cs for both Mark-IV ER and SOF-ER salts. However, for 154 Eu, it was 8% for SOF-ER salt and 7% for Mark-IV ER salt. Here, the main reason for the higher uncertainty for 154 Eu is believed to be the lower counting statistics in gamma spectroscopy. To improve the gamma radioactivity uncertainty of isotope 154 Eu, a longer data acquisition time (12 h instead of 4 h) and a higher count rate gamma detector for gamma spectroscopy were tested and it was found that the uncertainty for 154 Eu was significantly improved from 7% or 8–3%.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2026

Salt mass determination by 22 Na-based radioactive tracer dilution of a highly radioactive molten salt system for pyroprocessing spent oxide nuclear fuels

To demonstrate the feasibility of the 22 Na-based radioactive tracer dilution (RTD) for determining the total salt mass in a 60-kg oxide reduction (OR) system at Idaho National Laboratory (INL) for pyroprocessing spent oxide nuclear fuels, a LiCl- 22 NaCl tracer salt was prepared and spiked to the OR vessel, and salt samples were analyzed by gamma spectroscopy. Due to the high radioactivity (around 10 mCi/g) of the OR salt, mainly from 137 Cs, traditional gamma spectroscopy methods, which typically involve diluted salt samples, was not effective for analyzing the RTD samples. Since the 22 Na tracer radioactivity was very low, undiluted samples were necessary to detect the small amount of 22 Na tracer. Here, despite the high gamma radioactivity of the OR salt, increasing the detector-sample distance from 20 cm to 40 cm during gamma spectroscopy allowed the detection of radioactivity as low as 0.12 µCi/g 22 Na. The preparation of the 22 NaCl-LiCl tracer salt suitable for spiking into the OR salt was successful, and the mass determined by RTD was consistent with that estimated by salt level measurement. Therefore, the 22 Na-based RTD technique for total mass determination of the 60-kg molten salt system for OR is feasible, though more development work, particularly in the improving the uncertainty, is needed .

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

MOF-Transformed In 2 O 3-x @C Nanocorn Electrocatalyst for Efficient CO 2 Reduction to HCOOH

For electrochemical CO 2 reduction to HCOOH, an ongoing challenge is to design energy efficient electrocatalysts that can deliver a high HCOOH current density (J HCOOH ) at a low overpotential. Indium oxide is good HCOOH production catalyst but with low conductivity. In this work, we report a unique corn design of In 2 O 3-x @C nanocatalyst, wherein In 2 O 3-x nanocube as the fine grains dispersed uniformly on the carbon nanorod cob, resulting in the enhanced conductivity. Excellent performance is achieved with 84% Faradaic efficiency (FE) and 11 mA cm –2 J HCOOH at a low potential of – 0.4 V versus RHE. At the current density of 100 mA cm –2 , the applied potential remained stable for more than 120 h with the FE above 90%. Density functional theory calculations reveal that the abundant oxygen vacancy in In 2 O 3-x has exposed more In 3+ sites with activated electroactivity, which facilitates the formation of HCOO* intermediate. Operando X-ray absorption spectroscopy also confirms In 3+ as the active site and the key intermediate of HCOO* during the process of CO 2 reduction to HCOOH.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Dual active site tandem catalysis of metal hydroxyl oxides and single atoms for boosting oxygen evolution reaction

We report the high voltage in oxygen evolution reaction (OER) often causes structural change in electrocatalysts and forms multiple active sites. Therefore, exploring the synergy of various active sites is extremely significant to develop catalysts for OER with multiple elementary steps. Herein, we adopt the physically adsorbed metal ions method to successfully synthesize a highly-efficient electrocatalyst containing the dual active sites of Fe-NiOOH and NiC4 single atoms (marked as Ni SAs/Fe-NiOOH). The Ni SAs/Fe-NiOOH displays outstanding OER performance with an overpotential of 269 mV to deliver current density of 10 mA/cm 2 that shows 55 mV superior to commercial IrO 2 /CB at the same condition. Experiments and density functional theory calculations indicate that the excellent OER activity of Ni SAs/Fe-NiOOH catalyst is attributed to the synergy of dual active sites of NiC 4 SAs and Fe-NiOOH. A tandem catalysis mechanism is also proposed to reveal the synergism of two active centers, which makes the potential-determining step more facile and accordingly decreases the OER overpotential. This work offers a new concept of tandem catalysis to develop the electrocatalysts with many elemental steps, like OER and oxygen reduction reaction catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗