Engineering Papers⌕ Search

Engineering topics

Balossino, I.

Publications and source records attributed to Balossino, I..

86 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

First Study of Antihyperon-Nucleon Scattering Λ ¯ p → Λ ¯ p and Measurement of Λ p → Λ p Cross Section

Using ( 10.087 ± 0.044 ) × 10 9 J / ψ events collected with the BESIII detector at the BEPCII storage ring, the processes Λ p → Λ p and Λ ¯ p → Λ ¯ p are studied, where the Λ / Λ ¯ baryons are produced in the process J / ψ → Λ Λ ¯ and the protons are the hydrogen nuclei in the cooling oil of the beam pipe. Clear signals are observed for the two reactions. The cross sections in − 0.9 ≤ cos θ Λ / Λ ¯ ≤ 0.9 are measured to be σ ( Λ p → Λ p ) = ( 12.2 ± 1.6 stat ± 1.1 syst ) and σ ( Λ ¯ p → Λ ¯ p ) = ( 17.5 ± 2.1 stat ± 1.6 syst ) mb at the Λ / Λ ¯ momentum of 1.074 GeV / c within a range of ± 0.017 GeV / c , where the θ Λ / Λ ¯ are the scattering angles of the Λ / Λ ¯ in the Λ p / Λ ¯ p rest frames. Furthermore, the differential cross sections of the two reactions are also measured, where there is a slight tendency of forward scattering for Λ p → Λ p , and a strong forward peak for Λ ¯ p → Λ ¯ p . We present an approach to extract the total elastic cross sections by extrapolation. The study of Λ ¯ p → Λ ¯ p represents the first study of antihyperon-nucleon scattering, and these new measurements will serve as important inputs for the theoretical understanding of the (anti)hyperon-nucleon interaction. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Search for the production of deuterons and antideuterons in e + e − annihilation at center-of-mass energies between 4.13 and 4.70 GeV

Using a data sample of e + e − collision data corresponding to an integrated luminosity of 19 fb − 1 collected with the BESIII detector at the BEPCII collider, we search for the production of deuterons and antideuterons via e + e − → p p π − d ¯ + c . c . for the first time at center-of-mass energies between 4.13 and 4.70 GeV. No significant signal is observed and the upper limit of the e + e − → p p π − d ¯ + c . c . cross section is determined to be from 9.0 to 145 fb depending on the center-of-mass energy at the 90% confidence level. Published by the American Physical Society 2024

Ablikim, M.↗
DOE OSTI2024

Measurement of e + e − → η J / ψ cross section from s = 3.808 GeV to 4.951 GeV

Using data samples with an integrated luminosity of 22.42 fb − 1 collected by the BESIII detector operating at the BEPCII storage ring, we measure the cross sections of the e + e − → η J / ψ process at center-of-mass energies from 3.808 to 4.951 GeV. Three structures are observed in the line shape of the measured cross sections. A maximum-likelihood fit with ψ ( 4040 ) , two additional resonances, and a nonresonant component are performed. The mass and width of the first additional state are ( 4219.7 ± 2.5 ± 4.5 ) MeV / c 2 and ( 80.7 ± 4.4 ± 1.4 ) MeV , respectively, consistent with the ψ ( 4230 ) . For the second state, the mass and width are ( 4386 ± 13 ± 17 ) MeV / c 2 and ( 177 ± 32 ± 13 ) MeV , respectively, consistent with the ψ ( 4360 ) . The first uncertainties are statistical, and the second ones are systematic. The statistical significance of ψ ( 4040 ) is 8.0 σ and those for ψ ( 4230 ) and ψ ( 4360 ) are more than 10.0 σ . Published by the American Physical Society 2024

Ablikim, M.↗
DOE OSTI2024

Evidence of the singly Cabibbo suppressed decay Λ c + → p π 0

Evidence for the singly Cabibbo suppressed decay Λ c + → p π 0 is reported for the first time with a statistical significance of 3.7 σ based on 6.0 fb − 1 of e + e − collision data collected at center-of-mass energies between 4.600 and 4.843 GeV with the BESIII detector at the BEPCII collider. The absolute branching fraction of Λ c + → p π 0 is measured to be ( 1.5 6 − 0.58 + 0.72 ± 0.20 ) × 10 − 4 . Combining with the branching fraction of Λ c + → n π + , ( 6.6 ± 1.3 ) × 10 − 4 , the ratio of the branching fractions of Λ c + → n π + and Λ c + → p π 0 is calculated to be 3.2 − 1.2 + 2.2 . As an important input for the theoretical models describing the decay mechanisms of charmed baryons, our result indicates that the nonfactorizable contributions play an essential role and their interference with the factorizable contributions should not be significant. In addition, the absolute branching fraction of Λ c + → p η is measured to be ( 1.63 ± 0.3 1 stat ± 0.1 1 syst ) × 10 − 3 . Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

First Observation of a Three-Resonance Structure in e + e − → Nonopen Charm Hadrons

We report the measurement of the inclusive cross sections for e + e − → nOCH (where nOCH denotes non-open charm hadrons) with improved precision at center-of-mass (c.m.) energies from 3.645 to 3.871 GeV. We observe three resonances: R ( 3760 ) , R ( 3780 ) , and R ( 3810 ) with significances of 8.1 σ , 13.7 σ , and 8.8 σ , respectively. The R ( 3810 ) state is observed for the first time, while the R ( 3760 ) and R ( 3780 ) states are observed for the first time in the nOCH cross sections. Two sets of resonance parameters describe the energy-dependent line shape of the cross sections well. In set I [set II], the R ( 3810 ) state has mass ( 3805.7 ± 1.1 ± 2.7 ) [ ( 3805.7 ± 1.1 ± 2.7 ) ] MeV / c 2 , total width ( 11.6 ± 2.9 ± 1.9 ) [ ( 11.5 ± 2.8 ± 1.9 ) ] MeV , and an electronic width multiplied by the nOCH decay branching fraction of ( 10.9 ± 3.8 ± 2.5 ) [ ( 11.0 ± 3.4 ± 2.5 ) ] eV . In addition, we measure the branching fractions B [ R ( 3760 ) → nOCH ] = ( 25.2 ± 16.1 ± 30.4 ) % [ ( 6.4 ± 4.8 ± 7.7 ) % ] and B [ R ( 3780 ) → nOCH ] = ( 12.3 ± 6.6 ± 8.3 ) % [ ( 10.4 ± 4.8 ± 7.0 ) % ] for the first time. The R ( 3760 ) state can be interpreted as an open-charm (OC) molecular state, but containing a simple four-quark state component. The R ( 3810 ) state can be interpreted as a hadrocharmonium state. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Determination of Spin-Parity Quantum Numbers of X ( 2370 ) as 0 − + from J / ψ → γ K S 0 K S 0 η ′

Based on ( 10 087 ± 44 ) × 10 6 J / ψ events collected with the BESIII detector, a partial wave analysis of the decay J / ψ → γ K S 0 K S 0 η ′ is performed. The mass and width of the X ( 2370 ) are measured to be 2395 ± 11 ( stat ) − 94 + 26 ( syst ) MeV / c 2 and 188 − 17 + 18 ( stat ) − 33 + 124 ( syst ) MeV , respectively. The corresponding product branching fraction is B [ J / ψ → γ X ( 2370 ) ] × B [ X ( 2370 ) → f 0 ( 980 ) η ′ ] × B [ f 0 ( 980 ) → K S 0 K S 0 ] = ( 1.31 ± 0.22 ( stat ) − 0.84 + 2.85 ( syst ) ) × 10 − 5 . The statistical significance of the X ( 2370 ) is greater than 11.7 σ and the spin parity is determined to be 0 − + for the first time. The measured mass and spin parity of the X ( 2370 ) are consistent with the predictions of the lightest pseudoscalar glueball. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Measurement of Born cross section of $$ {e}^{+}{e}^{-}\to {\Sigma}^{+}{\overline{\Sigma}}^{-} $$ at center-of-mass energies between 3.510 and 4.951 GeV

Abstract Using 24.1 fb −1 ofe + e − collision data collected with the BESIII detector at the BEPCII collider, the Born cross sections and effective form factors of the$$ {e}^{+}{e}^{-}\to {\Sigma}^{+}{\overline{\Sigma}}^{-} $$ e + e − → Σ + Σ ¯ − reaction are measured. The measurements are performed at center-of-mass energies ranging from 3.510 to 4.951 GeV. No significant evidence for the decay of the charmonium(-like) states,ψ(3770),ψ(4040),ψ(4160),Y(4230),Y(4360),ψ(4415), andY(4660), into a$$ {\Sigma}^{+}{\overline{\Sigma}}^{-} $$ Σ + Σ ¯ − final state is observed. Consequently, upper limits for the products of the branching fractions and the electronic partial widths at the 90% confidence level are reported for these decays.

Physics↗
DOE OSTI2024

Search for ∆S = 2 nonleptonic hyperon decays Ω− → Σ0π− and Ω− → nK−

Abstract Using (27.12 ± 0.14) × 10 8 ψ(3686) events collected by the BESIII detector at the center-of-mass energy of$$ \sqrt{s} $$ s = 3.686 GeV, we search for the first time for two nonleptonic hyperon decays that change strangeness by two units, Ω − → Σ 0 π − and Ω − →nK − . No significant signal is observed. The upper limits on their decay branching fractions are determined to be$$ \mathcal{B} $$ B (Ω − → Σ 0 π − )<5.4 × 10 −4 and$$ \mathcal{B} $$ B (Ω − →nK − )<2.4 × 10 −4 at the 90% confidence level.

Physics↗
DOE OSTI2024

Measurement of absolute branching fractions of $$ {\textrm{D}}_{\textrm{s}}^{+} $$ hadronic decays

Abstract Usinge + e − collision data collected at the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV, corresponding to an integrated luminosity of 7.33 fb −1 , we determine the absolute branching fractions of fifteen hadronic$$ {D}_s^{+} $$ D s + decays with a double-tag technique. In particular, we make precise measurements of the branching fractions$$ \mathcal{B}\left({D}_s^{+}\to {K}^{+}{K}^{-}{\pi}^{+}\right)=\left(5.49\pm 0.04\pm 0.07\right)\% $$ B D s + → K + K − π + = 5.49 ± 0.04 ± 0.07 % ,$$ \mathcal{B}\left({D}_s^{+}\to {K}_S^0{K}^{+}\right)=\left(1.50\pm 0.01\pm 0.01\right)\% $$ B D s + → K S 0 K + = 1.50 ± 0.01 ± 0.01 % and$$ \mathcal{B}\left({D}_s^{+}\to {K}^{+}{K}^{-}{\pi}^{+}{\pi}^0\right)=\left(5.50\pm 0.05\pm 0.11\right)\% $$ B D s + → K + K − π + π 0 = 5.50 ± 0.05 ± 0.11 % , where the first uncertainties are statistical and the second ones are systematic. TheCPasymmetries in these decays are also measured and all are found to be compatible with zero.

Physics↗
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

Observation of the singly Cabibbo-suppressed decay Λ c + → Σ − K + π +

The singly Cabibbo-suppressed decay Λ c + → Σ − K + π + is observed for the first time with a statistical significance of 5.4 σ by using 4.5 fb − 1 of e + e − collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. The absolute branching fraction of Λ c + → Σ − K + π + is measured to be ( 3.8 ± 1.2 stat ± 0.2 syst ) × 10 − 4 in a model-independent approach. This is the first observation of a Cabibbo-suppressed Λ c + decay involving Σ − in the final state. The ratio of branching fractions between Λ c + → Σ − K + π + and the Cabibbo-favored decay Λ c + → Σ − π + π + is observed to be ( 0.4 ± 0.1 ) s c 2 , where s c ≡ sin θ c = 0.2248 with θ c the Cabibbo mixing angle. Published by the American Physical Society 2024

Astronomy & Astrophysics↗
DOE OSTI2024

Measurements of Born cross sections for e + e − → Λ c + Λ ¯ c ( 2595 ) − + c . c . and e + e − → Λ c + Λ ¯ c ( 2625 ) − + c . c . at s = 4918.0 and 4950.9 MeV

Using e + e − collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of e + e − → Λ c + Λ ¯ c ( 2595 ) − + c . c . and e + e − → Λ c + Λ ¯ c ( 2625 ) − + c . c . are measured for the first time at center-of-mass energies of s = 4918.0 and 4950.9 MeV. Nonzero cross sections are observed very close to the production threshold. The measured Born cross sections of e + e − → Λ c + Λ ¯ c ( 2625 ) − + c . c . are about 2–3 times greater than those of e + e − → Λ c + Λ ¯ c ( 2595 ) − + c . c . , providing the similar behavior as semileptonic decays of Λ b 0 , but different behavior from that in the hadronic decays of Λ b 0 . The Born cross sections are 15.6 ± 3.1 ± 0.9 pb and 29.4 ± 3.7 ± 2.7 pb for e + e − → Λ c + Λ ¯ c ( 2595 ) − + c . c . , and are 43.4 ± 4.0 ± 4.1 pb and 76.8 ± 6.5 ± 4.2 pb for e + e − → Λ c + Λ ¯ c ( 2625 ) − + c . c . at s = 4918.0 and 4950.9 MeV, respectively. Based on the polar angle distributions of the Λ ¯ c ( 2625 ) − and Λ c ( 2625 ) + , the form-factor ratios | G E | 2 + 3 | G M | 2 / | G C | are determined for e + e − → Λ c + Λ ¯ c ( 2625 ) − + c . c . for the first time, which are 5.95 ± 4.07 ± 0.15 and 0.94 ± 0.32 ± 0.02 at s = 4918.0 and 4950.9 MeV, respectively. All of these first uncertainties are statistical and second systematic. Published by the American Physical Society 2024

Astronomy & Astrophysics↗