| 1771. |
- Ablikim, M., et al.
(författare)
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Measurement of e plus e-? : ??0 cross sections at center-of-mass energies between 3.508 and 4.600 GeV
- 2023
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 107:7
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the dressed cross sections for e+e- -> phi eta at different center-of-mass energies between 3.508 and 4.600 GeV based on 15.1 fb-1 of e+e- annihilation data collected with the BESIII detector operating at the BEPCII collider. In addition, a search for the decay Y(4230) -> phi eta is performed. No clear signal is observed and the corresponding upper limit is provided.
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| 1772. |
- Ablikim, M., et al.
(författare)
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Measurement of integrated luminosities at BESIII for data samples at center-of-mass energies between 4.0 and 4.6 GeV
- 2022
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Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
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Tidskriftsartikel (refereegranskat)abstract
- The integrated luminosities of data samples collected in the BESIII experiment in 2016-2017 at center-of-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events. The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance, offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter, which can haphazardly occur.
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| 1773. |
- Ablikim, M., et al.
(författare)
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Measurement of J/psi -> Xi(1530+)(-) (Xi)over-bar(+) and evidence for the radiative decay Xi(153)(-) -> gamma Xi(-)
- 2020
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 101:1
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Tidskriftsartikel (refereegranskat)abstract
- The SU(3)-flavor violating decay J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c. is studied using (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector at BEPCII, and the branching fraction is measured to be B(J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c.) = (3.17 +/- 0.02(stat) +/- 0.08(syst)) x 10(-4). This result is consistent with previous measurements with an order of magnitude improved precision. The angular parameter for this decay is measured for the first time and is found to be alpha = -0.21 +/- 0.04(stat) +/- 0.06(syst). In addition, we report evidence for the radiative decay Xi(1530)(-) -> gamma Xi(-) with a significance of 3.9 sigma, including the systematic uncertainties. The 90% confidence level upper limit on the branching fraction is determined to be B(Xi(1530)(-) -> gamma Xi(-)) <= 3.7%.
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| 1774. |
- Ablikim, M., et al.
(författare)
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Measurement of Lambda baryon polarization in e(+) e(-) -> Lambda(Lambda)over-bar at root s=3.773 GeV
- 2022
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 105:1
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Forskningsöversikt (refereegranskat)abstract
- Using a data sample of psi(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb-1, we report a measurement of A spin polarization in e+ e- -> Lambda(Lambda) over bar at = root s = 3.773 GeV. The significance of polarization is found to be 2 sigma including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the Lambda(Lambda) over bar helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be Delta Phi(Psi) = Phi(Psi)(E) - Phi(Psi)(M) = (71(-46)(+66) +/- 5)degrees. Similarly, the ratio between the form factors is found to be R-psi = vertical bar G(E)(Psi)/G(M)(Psi)vertical bar = 0.48(-0.35)(+0.21) +/- 0.03. The first uncertainties are statistical and the second systematic.
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| 1775. |
- Ablikim, M., et al.
(författare)
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Measurement of Proton Electromagnetic Form Factors in e(+) e(-) -> p(p)over-bar in the Energy Region 2.00-3.08 GeV
- 2020
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:4
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Tidskriftsartikel (refereegranskat)abstract
- The process of e(+)e(-) -> p (p) over bar is studied at 22 center-of-mass energy points (root s) from 2.00 to 3.08 GeV, exploiting 688.5 pb(-1) of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section (sigma(p (p) over bar)) of e(+)e(-) -> p (p) over bar is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electro-magnetic form-factor ratio (vertical bar G(E)/G(M)vertical bar) and the value of the effective (vertical bar G(eff)vertical bar), electric (vertical bar G(E)vertical bar), and magnetic (vertical bar G(M)vertical bar) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. vertical bar G(E)/G(M)vertical bar and vertical bar G(M)vertical bar are determined with high accuracy, providing uncertainties comparable to data in the spacelike region, and vertical bar G(E)vertical bar is measured for the first time. We reach unprecedented accuracy, and precision results in the timelike region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on nonperturbative quantum chromodynamics.
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| 1776. |
- Ablikim, M., et al.
(författare)
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Measurement of proton electromagnetic form factors in the time-like region using initial state radiation at BESIII
- 2021
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 817
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Tidskriftsartikel (refereegranskat)abstract
- The electromagnetic process e(+)e(-) -> p (p) over bar over bar is studied with the initial-state-radiation technique using 7.5 fb(-1) of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/c(2) using the p (p) over bar over bar invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution.
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| 1777. |
- Ablikim, M., et al.
(författare)
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Measurement of psi(3686) -> Lambda(Lambda)over-bar eta and psi(3686) -> Lambda(Lambda)over-bar pi(0) decays
- 2022
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 106:7
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Tidskriftsartikel (refereegranskat)abstract
- Based on a sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector, a study of psi(3686) -> Lambda(Lambda) over bar pi(0) and psi(3686) -> Lambda(Lambda) over bar eta is performed. Evidence of the isospin-violating decay psi(3686) -> Lambda(Lambda) over bar pi(0) is found for the first time with a statistical significance of 3.7 sigma, the branching fraction B(psi(3686) -> Lambda(Lambda) over bar pi(0)) is measured to be (1.42 +/- 0.39 +/- 0.59) x 10(-6), and its corresponding upper limit is determined to be 2.47 x 10(-6) at 90% confidence level. A partial wave analysis of psi(3686) -> Lambda(Lambda) over bar eta shows that the peak around Lambda eta invariant mass threshold favors a Lambda* resonance with mass and width in agreement with the Lambda(1670). The branching fraction of the psi(3686) -> Lambda(Lambda) over bar eta is measured to be (2.34 +/- 0.18 +/- 0.52) x 10(-5). The first uncertainties are statistical and the second are systematic.
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| 1778. |
- Ablikim, M., et al.
(författare)
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Measurement of singly Cabibbo-suppressed decays D -> ωππ
- 2020
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Ingår i: Physical Review D. - : American Physical Society (APS). - 1550-7998 .- 1550-2368. ; 102:5
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Tidskriftsartikel (refereegranskat)abstract
- Using 2.93 fb(-1) of e(+) e(-) collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays D -> omega pi pi to be B(D-0 -> omega pi(+) pi(-)) = (1.33 +/- 0.16 +/- 0.12) x 10(-3) and B(D+ -> omega pi(+)pi(0)) = (3.87 +/- 0.83 +/- 0.25) x 10(-3), where the first uncertainties are statistical and the second ones systematic. The statistical significances are 12.9 sigma and 7.7 sigma, respectively. The precision of B(D-0 -> omega pi(+) pi(-)) is improved by a factor of 2.1 over prior measurements, and B(D+ -> omega pi(+) pi(0)) is measured for the first time. No significant signal for D-0 -> omega pi(0)pi(0) is observed, and the upper limit on the branching fraction is B(D-0 -> omega pi(0)pi(0)) < 1.10 x 10(-3) at the 90% confidence level. The branching fractions of D -> eta pi pi are also measured and consistent with existing results.
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| 1779. |
- Ablikim, M., et al.
(författare)
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Measurement of the Absolute Branching Fraction and Decay Asymmetry of Lambda -> n gamma
- 2022
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 129:21
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Tidskriftsartikel (refereegranskat)abstract
- The radiative hyperon decay Lambda -> n gamma is studied using (10087 +/- 44) x 10(6) J/psi. events collected with the BESIII detector operating at BEPCII. The absolute branching fraction of the decay Lambda -> n gamma is determined to be (0.832 +/- 0.038(stat) +/- 0.054(syst)) x 10(-3), which is a factor of 2.1 lower and 5.6 standard deviations different than the previous measurement. By analyzing the joint angular distribution of the decay products, the first determination of the decay asymmetry a. is reported with a value of -0.16 +/- 0.10(stat) +/- 0.05(syst).
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| 1780. |
- Ablikim, M., et al.
(författare)
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Measurement of the Absolute Branching Fraction of D+s→τ+ντ via τ+ → e+νe¯ντ
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 127:17
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Tidskriftsartikel (refereegranskat)abstract
- Using a dataset of 6.32 fb−1 of e+e− annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D+s→τ+ντ via τ+→e+νe¯ντ, and find BD+s→τ+ντ = (5.27±0.10±0.12)×10−2, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with fD+s from lattice quantum chromodynamics calculations or the |Vcs| from the CKMfitter group, we extract |Vcs|=0.978±0.009±0.012 and fD+s = (251.1±2.4±3.0) MeV, respectively. Combining our result with the world averages of BD+s→τ+ντ and BD+s→μ+νμ, we obtain the ratio of the branching fractions BD+s→τ+ντ/BD+s→μ+νμ = 9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.
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