Engineering topics

Adlarson, P.

Publications and source records attributed to Adlarson, P..

83 records · Page 5

DOE OSTI2024

Measurements of Normalized Differential Cross Sections of Inclusive η Production in e + e − Annihilation at Energy from 2.0000 to 3.6710 GeV

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, the cross section of the inclusive process e + e − → η + X , normalized by the total cross section of e + e − → hadrons , is measured at eight center-of-mass energy points from 2.0000 to 3.6710 GeV. These are the first measurements with momentum dependence in this energy region. Our measurement shows a significant discrepancy compared to the existing fragmentation functions. To address this discrepancy, a new QCD analysis is performed at the next-to-next-to-leading order with hadron mass corrections and higher twist effects, which can explain both the established high-energy data and our measurements reasonably well. Published by the American Physical Society 2024

Physics↗

DOE OSTI2024

Measurement of e+e− → ωη′ cross sections at $$ \sqrt{s} $$ = 2.000 to 3.080 GeV

Abstract We measured the Born cross sections for the processe + e − →ωη′ at 22 center-of-mass energies from 2.000 to 3.080 GeV with the BESIII detector at the BEPCII collider. We observed a resonant structure with a statistical significance of 9.6σ. A Breit-Wigner fit determines its mass to beM R = (2153±30±31) MeV/c 2 and its width to be Γ R = (167±77±7) MeV, where the first uncertainties are statistical and the second are systematic.

Physics↗

DOE OSTI2024

Study of η′ → π+π−l+l− decays at BESIII

Abstract With a sample of (10087±44)×10 6 J/ψevents accumulated with the BESIII detector, we analyze the decaysη′→ π + π − l + l − (l=e, μ) via the processJ/ψ → γη′. The branching fractions are measured to be$$ \mathcal{B} $$ B (η′→ π + π − e + e − ) = (2.45±0.02(stat.)±0.08(syst.))×10 −3 and$$ \mathcal{B} $$ B (η′→ π + π − μ + μ − ) = (2.16±0.12(stat.)±0.06(syst.))×10 −5 , and the ratio is$$ \frac{\mathcal{B}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{e}^{+}{e}^{-}\right)}{\mathcal{B}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)}=113.4\pm 0.9\left(\textrm{stat}.\right)\pm 3.7\left(\textrm{syst}.\right) $$ B η ′ → π + π − e + e − B η ′ → π + π − μ + μ − = 113.4 ± 0.9 stat . ± 3.7 syst . . In addition, by combining theη′ →π + π − e + e − andη′ →π + π − μ + μ − decays, the slope parameter of the electromagnetic transition form factor is measured to beb η′ = 1.30 ± 0.19 (GeV/c 2 ) −2 , which is consistent with previous measurements from BESIII and theoretical predictions from the VMD model. The asymmetry in the angle between theπ + π − andl + l − decay planes, which has the potential to reveal theCP-violation originating from an unconventional electric dipole transition, is also investigated. The asymmetry parameters are determined to be$$ {\mathcal{A}}_{CP}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{e}^{+}{e}^{-}\right)=\left(-0.21\pm 0.73\left(\textrm{stat}.\right)\pm 0.01\left(\textrm{syst}.\right)\right)\% $$ A CP η ′ → π + π − e + e − = − 0.21 ± 0.73 stat . ± 0.01 syst . % and$$ {\mathcal{A}}_{CP}\left({\eta}^{\prime}\to {\pi}^{+}{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)=\left(0.62\pm 4.71\left(\textrm{stat}.\right)\pm 0.08\left(\textrm{syst}.\right)\right)\% $$ A CP η ′ → π + π − μ + μ − = 0.62 ± 4.71 stat . ± 0.08 syst . % , implying that no evidence ofCP-violation is observed at the present statistics. Finally, an axion-like particle is searched for via the decayη′ →π + π − a, a→e + e − , and upper limits of the branching fractions are presented for the mass assumptions of the axion-like particle in the range of 0−500 MeV/c 2 .

Physics↗

DOE OSTI2024

Measurement of the cross sections of $$ {e}^{+}{e}^{-}\to {K}^{-}{\overline{\Xi}}^{+}\Lambda /{\Sigma}^0 $$ at center-of-mass energies between 3.510 and 4.914 GeV

Abstract Usinge + e − collision data collected with the BESIII detector at the BEPCII collider at center-of-mass energies between 3.510 and 4.914 GeV, corresponding to an integrated luminosity of 25 fb −1 , we measure the Born cross sections for the process$$ {e}^{+}{e}^{-}\to {K}^{-}{\overline{\Xi}}^{+}\Lambda /{\Sigma}^0 $$ e + e − → K − Ξ ¯ + Λ / Σ 0 at thirty-five energy points with a partial-reconstruction strategy. By fitting the dressed cross sections of$$ {e}^{+}{e}^{-}\to {K}^{-}{\overline{\Xi}}^{+}\Lambda /{\Sigma}^0 $$ e + e − → K − Ξ ¯ + Λ / Σ 0 , evidence for$$ \psi (4160)\to {K}^{-}{\overline{\Xi}}^{+}\Lambda $$ ψ 4160 → K − Ξ ¯ + Λ is found for the first time with a significance of 4.4σ, including systematic uncertainties. No evidence for other possible resonances is found. In addition, the products of electronic partial width and branching fraction for all assumed resonances decaying into$$ {K}^{-}{\overline{\Xi}}^{+}\Lambda /{\Sigma}^0 $$ K − Ξ ¯ + Λ / Σ 0 are determined.

Physics↗

DOE OSTI2024

Search for e + e − → K + K − ψ ( 3770 ) at center-of-mass energies from 4.84 to 4.95 GeV

Using e + e − collision data, corresponding to an integrated luminosity of 892 pb − 1 collected at center-of-mass energies from 4.84 to 4.95 GeV with the BESIII detector, we search for the process e + e − → K + K − ψ ( 3770 ) by reconstructing two charged kaons and one D meson from ψ ( 3770 ) . No significant signal of e + e − → K + K − ψ ( 3770 ) is found and the upper limits of the Born cross sections are reported at 90% confidence level. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

Cross section measurement of e + e − → η ψ ( 2 S ) and search for e + e − → η X ˜ ( 3872 )

The energy-dependent cross section for e + e − → η ψ ( 2 S ) is measured at 18 center of mass energies from 4.288 to 4.951 GeV using the BESIII detector. Using the same data samples, we also perform the first search for the reaction e + e − → η X ˜ ( 3872 ) , but no evidence is found for the X ˜ ( 3872 ) in the π + π − J / ψ mass distribution. At each of the 18 center of mass energies, upper limits at the 90% confidence level on the cross section for e + e − → η ψ ( 2 S ) and on the product of the e + e − → η X ˜ ( 3872 ) cross section with the branching fraction of X ˜ ( 3872 ) → π + π − J / ψ are reported. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

DOE OSTI2024

First measurements of the absolute branching fraction of Λ c ( 2625 ) + → Λ c + π + π − and upper limit on Λ c ( 2595 ) + → Λ c + π + π −

The absolute branching fraction of the decay Λ c ( 2625 ) + → Λ c + π + π − is measured for the first time to be ( 50.2 ± 5.7 stat ± 3.5 syst ) % with 368.48 pb − 1 of e + e − collision data collected by the BESIII detector at the center-of-mass energies of s = 4.918 and 4.950 GeV. Although the central value of the result is lower than the theoretical prediction of 67%, obtained from isospin symmetry, they are consistent taking the uncertainties into account. This is the first absolute branching fraction measurement for Λ c ( 2625 ) + since it was found. This measurement is necessary to obtain the coupling constants for the transitions between s -wave and p -wave charmed baryons in heavy hadron chiral perturbation theory. In addition, we search for the decay Λ c ( 2595 ) + → Λ c + π + π − . No significant signal is observed, and the upper limit on its branching fraction is determined to be 85.0% at the 90% confidence level. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

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↗