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Träfflista för sökning "WFRF:(Sun Xiao Feng) srt2:(2015-2019);srt2:(2017)"

Sökning: WFRF:(Sun Xiao Feng) > (2015-2019) > (2017)

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1.
  • Ablikim, M., et al. (författare)
  • Evidence for e+e−→γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 96:5
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>We present first evidence for the process e(+)e(-) -&gt; gamma eta(c)(1S) at six center-of-mass energies between 4.01 and 4.60 GeV using data collected by the BESIII experiment operating at BEPCII. We measure the Born cross section at each energy using a combination of twelve eta(c)(1S) decay channels. We also combine all six energies under various assumptions for the energy-dependence of the cross section. If the process is assumed to proceed via the Y(4260), we measure a peak Born cross section sigma(peak)(e(+)e(-) -&gt; gamma eta(c)(1S)) = 2.11 +/- 0.49 (stat.) +/- 0.36 (syst.) pb with a statistical significance of 4.2 sigma.</p>
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2.
  • Ablikim, M., et al. (författare)
  • Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -&gt; gamma gamma
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:9
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Based on 448.1 x 10(6) Psi(3686) events collected with the BESIII detector, the decays Psi(3686) -&gt; gamma chi(cJ), chi(cJ) -&gt; gamma gamma(J = 0, 1, 2) are studied. The decay branching fractions of chi(c0,2) -&gt; gamma gamma are measured to be B(chi(c0) -&gt; gamma gamma) = (1.93 +/- 0.08 +/- 0.05 +/- 0.05) x 10(-4) and B(chi(c2) -&gt; gamma gamma) = (3.10 +/- 0.09 +/- 0.07 +/- 0.11) x 10(-4) which correspond to two-photon decay widths of Gamma(gamma gamma)(chi(c0)) = 2.03 +/- 0.08 +/- 0.06 +/- 0.13 keV and Gamma(gamma gamma)(chi(c2)) = 0.60 +/- 0.02 +/- 0.01 +/- 0.04 keV with a ratio of R = Gamma(gamma gamma)(chi(c2))/Gamma(gamma gamma)(chi(c0)) = 0.295 +/- 0.014 +/- 0.007 +/- 0.027, where the uncertainties are statistical, systematic and associated with the uncertainties of B(Psi(3686) -&gt; gamma chi(c0,2)) and the total widths Gamma(chi(c0,2)), respectively. For the forbidden decay of chi(c1) -&gt; gamma gamma, no signal is observed, and an upper limit on the two-photon width is obtained to be Gamma(gamma gamma)(chi(c1)) &lt; 5.3 eV at the 90% confidence level. The ratio of the two-photon widths between helicity-zero and helicity-two components in the decay chi(c2) -&gt; gamma gamma is also measured to be f(0/2) = Gamma(lambda=0)(gamma gamma) (chi(c2))/Gamma(lambda=2)(gamma gamma) (chi(c2)) = (0.0 +/- 0.6 +/- 1.2) x 10(-2), where the uncertainties are statistical and systematic, respectively.</p>
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3.
  • Ablikim, M., et al. (författare)
  • Study of J/ψ and ψ(3686) decays to π<sup>+</sup>π<sup>−</sup>η′
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 96:11
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using the data samples of 1.31×10<sup>9</sup>  J/ψ events and 4.48×10<sup>8</sup>  ψ(3686) events collected with the BESIII detector, partial wave analyses on the decays J/ψ and ψ(3686)→π+π−η′ are performed with a relativistic covariant tensor amplitude approach. The dominant contribution is found to be J/ψ and ψ(3686) decays to ρη′. In the J/ψ decay, the branching fraction B(J/ψ→ρη′) is determined to be (7.90±0.19(stat)±0.49(sys))×10<sup>−5</sup>. Two solutions are found in the ψ(3686) decay, and the corresponding branching fraction B(ψ(3686)→ρη′) is (1.02±0.11(stat)±0.24(sys))×10<sup>−5</sup> for the case of destructive interference, and (5.69±1.28(stat)±2.36(sys))×10<sup>−6</sup> for constructive interference. As a consequence, the ratios of branching fractions between ψ(3686) and J/ψ decays to ρη′ are calculated to be (12.9±1.4(stat)±3.1(sys))% and (7.2±1.6(stat)±3.0(sys))%, respectively. We also determine the inclusive branching fractions of J/ψ and ψ(3686) decays to π+π−η′ to be (1.36±0.02(stat)±0.08(sys))×10<sup>−4</sup> and (1.51±0.14(stat)±0.23(sys))×10<sup>−5</sup>, respectively</p>
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4.
  • Ablikim, M., et al. (författare)
  • Study of J/ψ and ψ(3686) decay to Λ¯Λ and Σ0¯Σ0 final states
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 95:5
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using 1310.6 x 10(6) J/psi and 447.9 x 10(6) psi (3686) events collected with the BESIII detector at the BEPCII e(+)e(-) collider, the branching fractions and the angular distributions of J/psi and psi (3686) decays to Lambda(Lambda) over bar and Sigma(0)(Sigma) over tilde (0) final states are measured. The branching fractions are determined, with much improved precision, to be 19.43 +/- 0.03 +/- 0.33, 11.64 +/- 0.04 +/- 0.23, 3.97 +/- 0.02 +/- 0.12 and 2.44 +/- 0.03 +/- 0.11 for J/psi -&gt; Lambda(Lambda) over bar -&gt; Sigma(0)(Sigma) over tilde (0) , psi (3686) -&gt; Lambda(Lambda) over bar and psi (3686) -&gt; Sigma(0)(Sigma) over tilde (0), respectively. The polar angular distributions of psi (3686) decays are measured for the first time, while those of J/psi decays are measured with much improved precision. In addition, the ratios of branching fractions B(psi(3686)-&gt;Lambda(Lambda) over bar)/B(J/psi -&gt; Lambda(Lambda) over bar) and B(psi(3686)-&gt;Sigma(0)(Sigma) over tilde (0))/B(J/psi -&gt;Sigma(0)(Sigma) over tilde (0)) are determined to test the "12% rule."</p>
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5.
  • Ablikim, M., et al. (författare)
  • Branching fraction measurements of psi (3686) -&gt; gamma chi(cJ)
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 96:3
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using a sample of 106 million psi(3686) decays, the branching fractions of psi(3686) -&gt; gamma chi(c0), psi(3686) -&gt; gamma chi(c1), and psi(3686) -&gt; gamma chi(c2) are measured with improved precision to be (9.389 +/- 0.014 +/- 0.332) %, (9.905 +/- 0.011 +/- 0.353) %, and (9.621 +/- 0.013 +/- 0.272) %, respectively, where the first uncertainties are statistical and the second ones are systematic. The product branching fractions of (psi 3686) -&gt; gamma chi(c1), chi(c1) -&gt; gamma J/psi (3686) -&gt; gamma chi(c2), chi(c2) -&gt; gamma J/psi and the branching fractions of chi(c1) -&gt; gamma J/psi and chi(c2) -&gt; gamma J/psi are also presented.</p>
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6.
  • Ablikim, M., et al. (författare)
  • Measurement of branching fractions for psi(3686) -&gt; gamma eta ', gamma eta, and gamma pi(0)
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:5
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using a data sample of 448 x 10(6) psi(3686) events collected with the BESIII detector operating at the BEPCII storage ring, the decays psi(3686) -&gt; gamma eta and psi(3686) -&gt; gamma pi(0) are observed with a statistical significance of 7.3 sigma and 6.7 sigma, respectively. The branching fractions are measured to be B(psi(3686) -&gt; gamma eta) = (0.85 +/- 0.18 +/- 0.05) x 10(-6) and B(psi(3686) -&gt;gamma pi(0)) = (0.95 +/- 0.16 +/- 0.05) x 10(-6). In addition, we measure the branching fraction of psi(3686) -&gt; gamma eta' to be B(psi(3686) -&gt; gamma eta') = (125.1 +/- 2.2 +/- 6.2)x10(-6), which represents an improvement of precision over previous results.</p>
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7.
  • Ablikim, M., et al. (författare)
  • Observation of the decay Lambda(+)(c) -&gt; Sigma(-)pi(+)pi(+)pi(0)
  • 2017
  • Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 772, s. 388-393
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>We report the first observation of the decay Lambda(+)(c) -&gt; Sigma(-)pi(+)pi(+)pi(0), based on data obtained in e(+)e(-) annihilations with an integrated luminosity of 567 pb(-1) at vs = 4.6 GeV. The data were collected with the BESIII detector at the BEPCII storage rings. The absolute branching fraction B(Lambda(+)(c) -&gt; Sigma(-)pi(+)pi(+)pi(0)) is determined to be (2.11 +/- 0.33(stat.) +/- 0.14(syst.))%. In addition, an improved measurement of B(Lambda(+)(c) -&gt; Sigma(-)pi(+)pi(+)pi(0)) is determined as (1.81 +/- 0.17(stat.) +/- 0.09(syst.))%.</p>
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8.
  • Ablikim, M., et al. (författare)
  • Search for the rare decays J/ψ→D<sup>0</sup>e+e−+c.c. and ψ(3686)→D<sup>0</sup>e+e−+c.c.
  • 2017
  • Ingår i: BESIII Collaboration.
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using the data samples of (1310.6 +/- 7.2) x 10(6) J/psi events and (448.1 +/- 2.9) x 10(6) psi(3686) events collected with the BESIII detector, we search for the rare decays J/psi -&gt; D(0)e(+) e(-) + c.c. and psi(3686) -&gt; D(0)e(+) e(-) + c.c. No significant signals are observed and the corresponding upper limits on the branching fractions at the 90% confidence level are determined to be B(J/psi -&gt; D(0)e(+) e(-) + c.c.) &lt; 8.5 x 10(-8) and B(psi(3686) -&gt; D(0)e(+) e(-) + c.c.) &lt; 1.4 x 10(-7), respectively. Our limit on B(J/psi -&gt; D(0)e(+) e(-) + c.c.) is more stringent by 2 orders of magnitude than the previous results, and B(psi(3686) -&gt; D(0)e(+) e(-) + c.c.) is measured for the first time.</p>
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9.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis of D<sup>0</sup> -&gt; K<sup> -</sup>π<sup>+</sup>π<sup>+</sup>π<sup>-</sup>
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 95:7
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>We present an amplitude analysis of the decay D-0 -&gt; K- pi(+)pi(+)pi(-) based on a data sample of 2.93 fb(-1) acquired by the BESIII detector at the psi(3770) resonance. With a nearly background free sample of about 16000 events, we investigate the substructure of the decay and determine the relative fractions and the phases among the different intermediate processes. Our amplitude model includes the two-body decays D-0 -&gt; (K) over bar*(0)rho(0), D-0 -&gt; K- a(1)(+) (1260) and D-0 -&gt; K-1(-)(1270)pi(+), the three-body decays D-0 -&gt; K-1(-)*(0)pi(+)pi(-) and D-0 -&gt; K- pi(+)rho(0), as well as the four-body nonresonant decay D-0 -&gt; K- pi(+)pi(+)pi(-). The dominant intermediate process is D-0 -&gt; K(-)a(1)(+)(1260)accounting for a fit fraction of 54.6%.</p>
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10.
  • Ablikim, M., et al. (författare)
  • Amplitude analysis of the chi(c1) -&gt; eta pi(+)pi(-) decays
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using 448.0 x 10(6) psi(3686) events collected with the BESIII detector, an amplitude analysis is performed for psi(3686) -&gt; gamma chi(c1), chi(c1) -&gt;eta pi(+)pi(-) decays. The most dominant two- body structure observed is a(0)(980)(+/-) pi(-/+); a(0)(980)(+/-) -&gt; eta pi(+/-.) line shape is modeled using a dispersion relation, and a significant nonzero a(0) (980) coupling to the eta'pi channel is measured. We observe chi(c1) -&gt; a(2)(1700)pi production for the first time, with a significance larger than 17 sigma. The production of mesons with exotic quantum numbers, J(PC) = 1(-+), is investigated, and upper limits for the branching fractions chi(c1) -&gt; pi(1)(1400)(+/-)pi(-/+) , chi(c1) -&gt; pi(1)(1600)(+/-)pi(-/+) and chi(c1) -&gt; pi 1(2015)(+/-)pi(-/+) with subsequent pi(1)(X)(+/-) -&gt; eta pi(+/-) decay, are determined.</p>
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