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

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

  • Resultat 11-20 av 38
  • Föregående 1[2]34Nästa
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11.
  • Ablikim, M., et al. (författare)
  • Analysis of D+ -> (K)over-bar(0)e(+)nu(e) and D+ -> pi(0)e(+)nu(e) semileptonic decays
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:1
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using 2.93 fb(-1) of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays D+ -&gt; (K) over bar (0)e(+)nu(e) and D+ -&gt; pi(0)e(+)nu(e). We measure the absolute decay branching fractions B(D+ -&gt; (K) over bar (0)e(+)nu(e)) = (8.60 +/- 0.06 +/- 0.15) x 10(-2) and B(D+ -&gt; pi(0)e(+)nu(e)) = (3.63 +/- 0.08 +/- 0.05) x 10(-3), where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of |V-cs| and |V-cd| from Particle Data Group fits assuming Cabibbo-Kobayashi-Maskawa (CKM) unitarity, we obtain the values of the form factors at q(2) = 0, f(+)(K)(0) = 0.725 +/- 0.004 +/- 0.012, and f(+)(pi)(0) = 0.622 +/- 0.012 +/- 0.003. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements |V-cs| = 0.944 +/- 0.005 +/- 0.015 +/- 0.024 and |V-cd| = 0.210 +/- 0.004 +/- 0.001 +/- 0.009, where the third uncertainties are theoretical.</p>
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12.
  • Ablikim, M., et al. (författare)
  • Branching fraction measurement of J/ψ→K<sub>S</sub>K<sub>L</sub> and search for J/ψ→K<sub>S</sub>K<sub>S</sub>
  • 2017
  • Ingår i: BESIII Collaboration.
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using a sample of 1.31 x 10(9) J/Psi events collected with the BESIII detector at the BEPCII collider, we study the decays of J/Psi -&gt; KSKL and KSKS. The branching fraction of J/Psi -&gt; KSKL is determined to be B(J/Psi -&gt; KSKL) = (1.93 +/- 0.01 (stat) +/- 0.05 (syst)) x 10(-4), which significantly improves on previous measurements. No clear signal is observed for the J/Psi -&gt; KSKS process, and the upper limit at the 95% confidence level for its branching fraction is determined to be B(J/Psi -&gt; KSKS) &lt; 1.4 x 10(-8), which improves on the previous searches by 2 orders in magnitude and reaches the order of the Einstein-Podolsky-Rosen expectation.</p>
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13.
  • Ablikim, M., et al. (författare)
  • Determination of the Spin and Parity of the Z(c)(3900)
  • 2017
  • Ingår i: Physical Review Letters. - AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 119:7
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>The spin and parity of the Z(c)(3900)(+/-) state are determined to be J(P) = 1(+) with a statistical significance larger than 7 sigma over other quantum numbers in a partial wave analysis of the process e(+)e(-) -&gt; pi(+)pi(-) J/psi We use a data sample of 1.92 fb(-1) accumulated at root s = 4.23 and 4.26 GeV with the BESIII experiment. When parametrizing the Z(c)(3900)(+/-) with a Flatte-like formula, we determine its pole mass M-pole = (3881.2 +/- 4.2(stat) +/- 52.7(syst)) MeV/c(2) and pole width Gamma(pole) = (51.8 +/- 4.6(stat) +/- 36.0(syst)) MeV. We also measure cross sections for the process e(+)e(-) -&gt; Z(c)(3900)(+)pi(-) + c.c. -&gt; J/psi pi(+)pi(-) and determine an upper limit at the 90% confidence level for the process e(+)e(-) -&gt; Z(c)(4020)(+)pi(-) + c.c. -&gt; J/psi pi(+)pi(-).</p>
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14.
  • Ablikim, M., et al. (författare)
  • Evidence for the singly Cabibbo suppressed decay Lambda(+)(c) -&gt; p eta and search for Lambda(+)(c) -&gt; p pi(0)
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:11
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>We study the singly Cabibbo suppressed decays Lambda(+)(c) -&gt; p eta and Lambda(+)(c) -&gt; p pi(0) using Lambda(+)(c)(Lambda) over bar (-)(c) pairs produced by e(+)e(-) collisions at a center-of-mass energy of root s = 4.6 GeV. The data sample was collected by the BESIII detector at the BEPCII collider and corresponds to an integrated luminosity of 567 pb(-1). We find the first evidence for the decay Lambda(+)(c) -&gt; p eta with a statistical significance of 4.2 sigma and measure its branching fraction to be B(Lambda(+)(c) -&gt; p eta) = (1.24 +/- 0.28(stat) +/- 0.10(sys)) x 10(-3). No significant Lambda(+)(c) -&gt; p pi(0) signal is observed. We set an upper limit on its branching fraction B(Lambda(+)(c) -&gt; p pi(0)) &lt; 2.7 x 10(-4) at the 90% confidence level.</p>
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15.
  • Ablikim, M., et al. (författare)
  • Evidence of Two Resonant Structures in e(+)e(-)-&gt;pi(+) pi(-) h(c)
  • 2017
  • Ingår i: Physical Review Letters. - AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 118:9
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>The cross sections of e(+)e(-) -&gt; pi(+) pi(-) hc at center-of-mass energies from 3.896 to 4.600 GeVare measured using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The cross sections are found to be of the same order of magnitude as those of e(+)e(-) -&gt; pi(+) pi(-) J/psi and e(+)e(-) -&gt; pi(+) pi(-) psi (2S), but the line shape is inconsistent with the Y states observed in the latter two modes. Two structures are observed in the e(+)e(-) -&gt; pi(+) pi(-) hc cross sections around 4.22 and 4.39 GeV/c(2), which we call Y(4220)and Y(4390), respectively. A fit with a coherent sum of two Breit-Wigner functions results in a mass of (4218.4(- 4.5)(vertical bar 5.5) +/- 0.9) MeV/ c(2) and a width of (66.0(- 8.3)(vertical bar 12.3) +/- 0.4) MeV for the Y(4220), and a mass of (4391.5(- 6.8)(+6.3) +/- 1.0) MeV/c(2) and a width of (139.5(- 20.6)(+16.2) +/- 0.6) MeV for the Y(4390), where the first uncertainties are statistical and the second ones systematic. The statistical significance of Y(4220) and Y(4390) is 10 sigma over one structure assumption.</p>
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16.
  • Ablikim, M., et al. (författare)
  • Improved measurements of branching fractions for eta(c) -&gt; phi phi and omega phi
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:9
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using (223.7 +/- 1.4) x 10(6) J / Psi events accumulated with the BESIII detector, we study eta(c) decays to phi phi and omega phi final states. The branching fraction of n(c) -&gt; phi phi is measured to be Br(eta(c) -&gt; phi phi) = (2.5 +/- 0(-0.7)(+0.3) +/- 0.6) X 10(-3,) where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of Br(J / Psi -&gt; gamma eta(C)). No significant signal for the double Okubo-Zweig-Iizuka suppressed decay of eta(c) -&gt; omega phi is observed, and the upper limit on the branching fraction is determined to be Br(eta(c) -&gt; omega phi) &lt; 2.5 x 10(-4) at the 90% confidence level.</p>
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17.
  • Ablikim, M., et al. (författare)
  • Measurement of cross sections of the interactions e(+)e(-) -&gt; phi phi omega and e(+)e(-) -&gt; phi phi phi at center-of-mass energies from 4.008 to 4.600 GeV
  • 2017
  • Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 774, s. 78-86
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Using data samples collected with the BESIII detector at the BEPCII collider at six center-of-mass energies between 4.008 and 4.600 GeV, we observe the processes e(+)e(-) -&gt; phi phi omega and e(-)e(-) -&gt; phi phi phi. The Born cross sections are measured and the ratio of the cross sections sigma(e(+)e(-) -&gt; phi phi omega)/sigma(e(-)e(-) -&gt; phi phi phi) is estimated to be 1.75 +/- 0.22 +/- 0.19 averaged over six energy points, where the first uncertainty is statistical and the second is systematic. The results represent first measurements of these interactions.</p>
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18.
  • Ablikim, M., et al. (författare)
  • Measurement of e(+)e(-) -&gt; pi(+)pi(-) psi(3686) from 4.008 to 4.600 GeV and observation of a charged structure in the pi(+/-)psi(3686) mass spectrum
  • 2017
  • Ingår i: Physical Review D : covering particles, fields, gravitation, and cosmology. - 2470-0010 .- 2470-0029. ; 96:3
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>We study the process e(+)e(-) -&gt; p(+)p(-)psi(3686) using 5.1 fb(-1) of data collected at 16 center-of-mass energy (root s) points from 4.008 to 4.600 GeV by the BESIII detector operating at the BEPCII collider. The measured Born cross sections for e(+)e(-) -&gt; p(+)p(-)psi(3686) are consistent with previous results, but with much improved precision. A fit to the cross section shows contributions from two structures: the first has M = 4209.5 +/- 7.4 +/- 1.4 MeV/c(2) and Gamma = 80.1 +/- 24.6 +/- 2.9 MeV, and the second has M = 4383.8 +/- 4.2 +/- 0.8 MeV/c(2) and Gamma = 84.2 +/- 12.5 +/- 2.1 MeV, where the first errors are statistical and the second systematic. The lower-mass resonance is observed in the process e(+)e(-) -&gt; p(+)p(-)psi(3686) for the first time with a statistical significance of 5.8 sigma. A charged charmoniumlike structure is observed in the pi(+/-)psi(3686) invariant mass spectrum for data at root s = 4.416 GeV. A fit with an S-wave Breit-Wigner function yields a mass M = 4032.1 +/- 2.4 MeV/c(2), where the errors are statistical only. However, there are still unresolved discrepancies between the fit model and data. The width of the intermediate state varies in a wide range for different kinematic regions within the data set. Therefore, no simple interpretation of the data has been found, and a future data sample with larger statistics and more theoretical input will be required to better understand this issue.</p>
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19.
  • Ablikim, M., et al. (författare)
  • Measurement of integrated luminosity and center-of-mass energy of data taken by BESIII at √<em>s</em>=2.125 GeV
  • 2017
  • Ingår i: Chinese Physics C, High Energy Physics & Nuclear Physics. - 1674-1137 .- 0899-9996. ; 41:11
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>To study the nature of the state Y (2175), a dedicated data set of e(+)e(-) collision data was collected at the center-of-mass energy of 2.125 GeV with the BESIII detector at the BEPCII collider. By analyzing large-angle Bhabha scattering events, the integrated luminosity of this data set is determined to be 108.49 +/- 0.02 +/- 0.85 pb(-1), where the first uncertainty is statistical and the second one is systematic. In addition, the center-of-mass energy of the data set is determined with radiative dimuon events to be 2126.55 +/- 0.03 +/- 0.85 MeV, where the first uncertainty is statistical and the second one is systematic.</p>
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20.
  • Ablikim, M., et al. (författare)
  • Measurements of cross section of e(+)e(-) -&gt; p(p)over-bar pi(0) at center-of-mass energies between 4.008 and 4.600 GeV
  • 2017
  • Ingår i: Physics Letters B. - ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 771, s. 45-51
  • Tidskriftsartikel (refereegranskat)abstract
    • <p>Based on e(+)e(-) annihilation data samples collected with the BESIII detector at the BEPCII collider at 13 center-of-mass energies from 4.008 to 4.600 GeV, measurements of the Born cross section of e(+)e(-) -&gt; p (p) over bar pi(0) are performed. No significant resonant structure is observed in the measured energy dependence of the cross section. The upper limit on the Born cross section of e(+)e(-) -&gt; Y (4260) -&gt; p (p) over bar pi(0) at the 90% C. L. is determined to be 0.01 pb. The upper limit on the ratio of the branching fractions B(Y(4260) -&gt; p (p) over bar pi(0))/B(Y(4260) -&gt; pi(+)pi(-) j/Psi) at the 90% C. L. is determined to be 0.02%.</p>
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  • Resultat 11-20 av 38
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