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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Search for the semi-leptonic decays Λ c + → Λ π + π - e + ν e and Λ c + → p K S 0 π - e + ν e

We search for the semi-leptonic decays $Λ^+_c$ → Λπ + π - e + ν e and $Λ^+_c$ → p$K^0_S$π - e + ν e in a sample of 4.5 fb -1 of e + e - annihilation data collected in the center-of-mass energy region between 4.600 GeV and 4.699 GeV by the BESIII detector at the BEPCII. No significant signals are observed, and the upper limits on the decay branching fractions are set to be B($Λ^+_c$ → Λπ + π - e + ν e ) < 3.9 × 10 -4 and B($Λ^+_c$ → p$K^0_S$π - e + ν e ) < 3.3 × 10 -4 at the 90% confidence level, respectively

$Λ^+_c$↗
DOE OSTI2024

Extracting the femtometer structure of strange baryons using the vacuum polarization effect

Abstract One of the fundamental goals of particle physics is to gain a microscopic understanding of the strong interaction. Electromagnetic form factors quantify the structure of hadrons in terms of charge and magnetization distributions. While the nucleon structure has been investigated extensively, data on hyperons are still scarce. It has recently been demonstrated that electron-positron annihilations into hyperon-antihyperon pairs provide a powerful tool to investigate their inner structure. We present a method useful for hyperon-antihyperon pairs of different types which exploits the cross section enhancement due to the effect of vacuum polarization at theJ/ψresonance. Using the 10 billionJ/ψevents collected with the BESIII detector, this allows a precise determination of the hyperon structure function. The result is essentially a precise snapshot of the$$\bar{\Lambda }{\Sigma }^{0}\,(\Lambda {\bar{\Sigma }}^{0})$$ Λ ¯ Σ 0 ( Λ Σ ¯ 0 ) transition process, encoded in the transition form factor ratio and phase. Their values are measured to beR = 0.860 ± 0.029(stat.) ± 0.015(syst.),$$\Delta {\Phi }_{\bar{\Lambda }{\Sigma }^{0}}=(1.011\pm 0.094({{\rm{stat.}}})\pm 0.010({{\rm{syst.}}}))\,{{\rm{r}}}ad$$ Δ Φ Λ ¯ Σ 0 = ( 1.011 ± 0.094 ( stat. ) ± 0.010 ( syst. ) ) r a d and$$\Delta {\Phi }_{\Lambda {\bar{\Sigma }}^{0}}=(2.128\pm 0.094({{\rm{stat.}}})\pm 0.010({{\rm{syst.}}}))\,{{\rm{r}}}ad$$ Δ Φ Λ Σ ¯ 0 = ( 2.128 ± 0.094 ( stat. ) ± 0.010 ( syst. ) ) r a d . Furthermore, charge-parity (CP) breaking is investigated in this reaction and found to be consistent with CP symmetry.

Science & Technology - Other Topics↗
DOE OSTI2022

Luminosities and energies of e + e - collision data taken between $\sqrt{s}$=4.61 GeV and 4.95 GeV at BESIII*

From December 2019 to June 2021, the BESIII experiment collected approximately 5.85 fb -1 of data at center-of-mass energies between 4.61 and 4.95 GeV. This is the highest collision energy BEPCII has reached to date. The accumulated e + e - annihilation data samples are useful for studying charmonium(-like) states and charmed-hadron decays. By adopting a novel method of analyzing the production of $Λ^{+}_{c}$ $\overline{Λ}$ $^{-}_{c}$ pairs in e + e - annihilation, the center-of-mass energies are measured with a precision of ~0.6 MeV. Integrated luminosities are measured with a precision of better than 1% by analyzing the events of large-angle Bhabha scattering. These measurements provide important inputs to analyses based on these data samples.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Observation of the Y(4230) and a new structure in ${\boldsymbol e^+\boldsymbol e^- \boldsymbol\rightarrow \boldsymbol K^+\boldsymbol K^-\boldsymbol J/\boldsymbol\psi}$

The cross sections of $e^+e^- \rightarrow K^+K^-J/\psi$ at center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb -1 data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in the line shape of the cross sections. The mass and width of the first structure are measured to be ($4225.3\pm2.3\pm21.5$) MeV and ($72.9\pm6.1\pm30.8$) MeV, respectively. They are consistent with those of the established $Y(4230)$. The second structure is observed for the first time with a statistical significance greater than 8σ, denoted as $Y(4500)$. Its mass and width are determined to be ($4484.7\pm13.3\pm24.1$) MeV and ($111.1\pm30.1\pm15.2$) MeV, respectively. The first presented uncertainties are statistical and the second ones are systematic. The product of the electronic partial width with the decay branching fraction $\Gamma(Y(4230)\to e^+ e^-) \mathcal{B}(Y(4230) \to K^+ K^- J/\psi)$ is reported.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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 OSTI2022

Observations of the Cabibbo-Suppressed decays $Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ 0 , $\mathcal{n}$$π$ + $π$ - $π$ + and the Cabibbo-Favored decay $Λ^{+}_{c}$ → $\mathcal{n}$$K$ - $π$ + $π$ + *

Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb -1 , collected by the BESIII detector in the energy region between $4599.53$ $MeV$ and $4698.82$ $MeV$ we report the first observations of the Cabibbo-suppressed decays $Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ 0 , $Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ - $π$ + , and the Cabibbo-favored decay $Λ^{+}_{c}$ → $\mathcal{n}$$K$ - $π$ + $π$ + with statistical significances of $7.9σ$, $7.8σ$, and Misplaced &, respectively. The branching fractions of these decays are measured to be $\mathcal{B}$($Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ 0 ) = ($0.64 ± 0.09 ± 0.02$)%, $\mathcal{B}$($Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ - $π$ + ) = ($0.45 ± 0.07 ± 0.03$)%, and $\mathcal{B}$ $Λ^{+}_{c}$ → $\mathcal{n}$$K$ - $π$ + $π$ + ) = ($1.90 ± 0.08 ± 0.09$)% where the first uncertainties are statistical and the second are systematic. We find that the branching fraction of the decay $Λ^{+}_{c}$ → $\mathcal{n}$$π$ + $π$ 0 is about one order of magnitude higher than that of $Λ^{+}_{c}$ → $\mathcal{n}$ $π$ + .

$Λ^{+}_{c}$ baryon↗
DOE OSTI2022

Search for hidden-charm tetraquark with strangeness in e + e - → $K$ + $D^{*}_{s}$ - $D$ *0 + c.c.*

We report a search for a heavier partner of the recently observed Z cs (3985) - state, denoted as $Z^{'-}_{cs}$, in the process e + e - → $K$ + $D^{*}_{s}$ - $D$ *0 + c.c., based on e + e - collision data collected at the center-of-mass energies of $\sqrt{s}$ = 4.661, 4.682 and 4.699 GeV with the BESIII detector. The $Z^{'-}_{cs}$ is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate K + recoil-mass spectra, which are probed for a potential contribution from $Z^{'-}_{cs}$ → $D^{*}_{s}$ - $D$ *0 + (c.c.). We find an excess of $Z^{'-}_{cs}$ → $D^{*}_{s}$ - $D$ *0 + (c.c.) candidates with a significance of 2.1σ, after considering systematic uncertainties, at a mass of 4123.5 ± 0.7 stat. ± 4.7 syst. ) MeV/c 2 . As the data set is limited in size, the upper limits are evaluated at the 90% confidence level on the product of the Born cross sections (σ BORN ) and the branching fraction ($\mathcal{B}$) of $Z^{'-}_{cs}$ → $D^{*}_{s}$ - $D$ *0 , under different assumptions of the $Z^{'-}_{cs}$ mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies. The upper limits of σ BORN ∙ $\mathcal{B}$ are found to be at the level of $\mathcal{O}$(1) pb at each energy. Larger data samples are needed to confirm the $Z^{'-}_{cs}$ state and clarify its nature in the coming years.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Observation of e⁺e⁻ → pp$\bar{p}\bar{n}\pi^-$ + c. c.

Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESIII detector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8 fb -1 , the process e⁺e⁻ → pp$\overline{p}\overline{n}\pi^-$ + c. c. is observed for the first time with a statistical significance of 11.5σ. The average Born cross sections in the energy ranges of (4.160, 4.380) GeV, (4.400, 4.600) GeV and (4.610, 4.700) GeV are measured to be (21.5 ± 5.7 ± 1.2) fb, (46.3 ± 10.6 ± 2.5) fb and (59.0 ± 9.4 ± 3.2) fb, respectively, where the first uncertainties are statistical and the second are systematic. The line shapes of the $\overline{p}\overline{n}$ and ppπ⁻ invariant mass spectra are consistent with phase space distributions, indicating that no hexaquark or di-baryon state is observed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Amplitude analysis of the decays and *

Abstract Usingannihilation data corresponding to an integrated luminosity of 2.93taken at the center-of-mass energyGeV with the BESIII detector, a joint amplitude analysis is performed on the decaysand(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays,,, andare observed in both channels. With the obtained amplitude model, the-even fractions ofand(non-η) are determined to be% and%, respectively. The branching fractions ofand(non-η) are measured to be% and%, respectively. The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters ofwhen used to determine the CKM anglevia thedecay.

Physics↗
DOE OSTI2025

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↗