| 1531. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3686) -> eta ' e(+)e(-)
- 2018
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Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 783, s. 452-458
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay psi(3686) -> eta'e(+)e(-), with significances of 7.0 sigma and 6.3 sigma when reconstructing the eta' meson via its decay modes eta' -> gamma pi(+)pi(-) and eta' -> pi(+)pi(-) eta (eta -> gamma gamma), respectively. The weighted average branching fraction is determined to be B(psi(3686) -> eta'e(+)e(-)) = (1.90 +/- 0.25 +/- 0.11) x 10(-6), where the first uncertainty is statistical and the second systematic.
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| 1532. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3686) -> p(p)over-bar eta ' and improved measurement of J/psi -> p(p)over-bar eta '
- 2019
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 99:3
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Tidskriftsartikel (refereegranskat)abstract
- We observe the process psi(3686) -> p (p) over bar eta' for the first time, with a statistical significance higher than 10 sigma, and measure the branching fraction of J/psi -> p (p) over bar eta' with an improved accuracy compared to earlier studies. The measurements are based on 4.48 x 10(8) psi(3686) and 1.31 x 10(9) J/psi events collected by the BESIII detector operating at the BEPCII. The branching fractions are determined to be B(psi(3686) -> p (p) over bar eta') = (1.10 +/- 0.10 +/- 0.08) x 10(-5) and B(J/psi -> p (p) over bar eta' = (1.26 +/- 0.02 +/- 0.07) x 10(-4), where the first uncertainties are statistical and the second ones systematic. Additionally, the eta - eta' mixing angle is determined to be -24 degrees +/- 11 degrees based on psi(3686) -> p (p) over bar eta', and -24 degrees +/- 9 degrees based on J/psi -> p (p) over bar eta', respectively.
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| 1533. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3686) -> p(p)over-bar phi
- 2019
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 99:11
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 4.48 x 10(8) psi(3686) events collected with the BESIII detector, we present a first observation of psi(3686) -> p (p) over bar phi, and we measure its branching fraction to be [6.06 +/- 0.38(stat)+/- 0.48(syst)] x 10(-6). In contrast to the earlier discovery of a threshold enhancement in the p (p) over bar -mass spectrum of the channel j/psi -> gamma p (p) over bar, denoted as X(p (p) over bar), we do not find a similar enhancement in psi(3686) -> p (p) over bar phi. An upper limit of 1.82 x 10(-7) at the 90% confidence level on the branching fraction of psi(3686) -> X(p (p) over bar)phi -> p (p) over bar phi is obtained.
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| 1534. |
- Ablikim, M., et al.
(författare)
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Observation of psi (3686) ->Xi (1530)(0) (Xi)over-bar (1530)(0) and Xi (1530)(0) (Xi)over-bar(0)
- 2021
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:9
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Tidskriftsartikel (refereegranskat)abstract
- Using (448.1 +/- 2.9) x 10(6) psi (3686) events collected with the BESIII detector and a single-baryon tagging technique, we present the first observation of the decays psi(3686)-> Xi (1530)(0) (Xi) over bar (1530)(0) and Xi (1530)(0) (Xi) over bar (0). The branching fractions are measured to be B psi (3686)-> Xi (1530)(0) (Xi) over bar (1530)(0)) = (6.77 +/- 0.14 +/- 0.39 x 10(- 5) and B (psi(3686)-> Xi (1530)(0) (Xi) over bar (0) = (0.53 +/- 0.04 +/- 0.03) x 10(-5). Here, the first and second uncertainties are statistical and systematic, respectively. In addition, the parameter associated with the angular distribution for the decay psi (3686) ->Xi (1530)(0) (Xi) over bar (1530)(0) is determined to be alpha= 1/4 0.32 +/- 0.19 +/- 0.07, in agreement with theoretical predictions within one standard deviation.
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| 1535. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3770) -> eta J/psi
- 2023
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 107:9
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, the Born cross section of the process e+e- -> eta J=psi at a center-of-mass energy pffisffi = 3.773 GeV is measured to be (8.88 +/- 0.87 +/- 0.42) pb. We fit the cross section line shape before correcting for the initial state radiation ffiffifromps = 3.773 to 4.600 GeV to obtain the branching fraction B(psi(3770) -> eta J=psi). We obtain B(psi(3770) -> eta J=psi) = (11.3 +/- 5.9 +/- 1.1) x 10-4 when the psi(3770) decay amplitude is added coher-ently to the other contributions, and (8.7 +/- 1.0 +/- 0.8) x 10-4 when it is added incoherently. Here the quoted uncertainties are statistical and systematic, respectively. In both cases, the statistical significance of psi(3770) resonance is above 7 sigma. This is the first time the decay psi(3770) -> eta J=psi is observed with a statistical significance greater than 5 sigma.
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| 1536. |
- Ablikim, M., et al.
(författare)
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Observation of psi(3886) -> Xi(1530)(-)(Xi)over-bar(1530)(+) and Xi(1530)(-)(Xi)over-bar(+)
- 2019
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 100:5
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Tidskriftsartikel (refereegranskat)abstract
- Using 448.1 x 10(6) psi(3686) events collected with the BESIII detector at BEPCII, we employ a single-baryon tagging technique to make the first observation of psi(3686) -> Xi(1530)(-)(Xi) over bar (1530)(+) and Xi(1530)(-)(Xi) over bar (+) decays with a statistical significance of more than 10 sigma and 5.0 sigma, respectively. The branching fractions are measured to be B(psi(3686) -> Xi(1530)(-)(Xi) over bar (1530)(+)) = (11.45 +/- 0.40 +/- 0.59) x 10(-5) and B(psi(3686) -> Xi(1530)(-)(Xi) over bar (+)) = (0.70 +/- 0.11 +/- 0.04) x 10(-5). The angular distribution parameter for psi(3686) -> Xi(1530)(-)(Xi) over bar (1530)(+) is determined to be alpha = 0.40 +/- 0.24 +/- 0.06, which agrees with the theoretical predictions within 1 sigma. The first uncertainties are statistical, and the second systematic.
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| 1537. |
- Ablikim, M., et al.
(författare)
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Observation of Resonance Structures in e(+) e(-) -> pi(+) pi(- )psi(2)(3823) and Mass Measurement of psi(2)(3823)
- 2022
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 129:10
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Tidskriftsartikel (refereegranskat)abstract
- Using a data sample corresponding to an integrated luminosity of 11.3 fb(-1) collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e(+) e(-) -> pi(+) pi(-) psi(2)(3823) cross section and the branching fraction B[psi(2) (3823) -> gamma chi(c1)]. For the first time, resonance structure is observed in the cross section line shape of e(+) e(-) -> pi(+) pi(-) psi(2)(3823) with significances exceeding 5 sigma. A fit to data with two coherent Breit-Wigner resonances modeling the root s-dependent cross section yields M(R-1) = 4406.9 +/- 17.2 +/- 4.5 MeV/c(2), Gamma(R-1) = 128.1 +/- 37.2 +/- 2.3 MeV, and M(R-2) = 4647.9 +/- 8.6 +/- 0.8 MeV/c2, Gamma(R-2) = 33.1 +/- 18.6 +/- 4.1 MeV. Though weakly disfavored by the data, a single resonance with M(R) = 4417.5 +/- 26.2 +/- 3.5 MeV/c(2), Gamma(R) = 245 +/- 48 +/- 13 MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the psi(2)(3823) state is measured as (3823.12 +/- 0.43 +/- 0.13) MeV/c(2), which is the most precise measurement to date.
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| 1538. |
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| 1539. |
- Ablikim, M., et al.
(författare)
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Observation of Significant Flavor-SU(3) Breaking in the Kaon Wave Function at 12 < Q2 < 25 GeV2 and Discovery of the Charmless Decay ψ(3770) → K0SK0L
- 2024
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:13
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Tidskriftsartikel (refereegranskat)abstract
- We present cross sections for the reaction e+e− → K0SK0L at center-of-mass energies ranging from 3.51 to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb−1. The ratio of neutral-to-charged kaon form factors at large momentum transfers (12 < Q2 < 25 GeV2) is determined to be 0.21±0.01, which indicates a small but significant effect of flavor-SU(3) breaking in the kaon wave function, and, consequently, excludes the possibility that flavor-SU(3) breaking is the primary reason for the strong experimental violation of the pQCD prediction |F(π±)|/|F(K±)|=f2π/f2K, where F(π±) and F(K±) are the form factors, and fπ and fK are the decay constants of charged pions and kaons, respectively. We also observe a significant signal for the charmless decay ψ(3770) → K0SK0L for the first time. Within a 1σ contour of the likelihood value, the branching fraction for ψ(3770) → K0SK0L is determined to be B = (2.63+1.40−1.59)×10−5, and the relative phase between the continuum and ψ(3770) amplitudes is ϕ = (−0.39+0.05−0.10)π. The branching fraction is in good agreement with the S- and D-wave charmonia mixing scheme proposed in the interpretation of the “ρπ puzzle” between J/ψ and ψ(3686) decays.
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| 1540. |
- Ablikim, M., et al.
(författare)
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Observation of the Dalitz decay eta ' -> gamma e(+)e(-)
- 2015
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
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Tidskriftsartikel (refereegranskat)abstract
- We report the first observation of the Dalitz decay eta' -> gamma e(+)e(-), based on a data sample of 1.31 billion J/psi events collected with the BESIII detector. The eta' mesons are produced via the J/psi -> gamma eta' decay process. The ratio (eta' -> gamma e(+)e(-))/Gamma (eta' -> gamma gamma) is measured to be (2.13 +/- 0.09(stat) +/- 0.07(sys)) x 10(-2). This corresponds to a branching fraction B(eta' -> gamma e(+)e(-)) = (4.69 +/- 0.20(stat) +/- 0.23(sys)) x 10(-4). The transition form factor is extracted and different expressions are compared to the measured dependence on the e(+)e(-) invariant mass. The results are consistent with the prediction of the vector meson dominance model.
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