| 11. |
- Collaboration, The PANDA, et al.
(author)
-
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
- 2016
-
In: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10
-
Journal article (peer-reviewed)abstract
- Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
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| 12. |
- Ablikim, M., et al.
(author)
-
Branching fraction measurement of J/ψ→KSKL and search for J/ψ→KSKS
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:11
-
Journal article (peer-reviewed)abstract
- 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 -> KSKL and KSKS. The branching fraction of J/Psi -> KSKL is determined to be B(J/Psi -> 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 -> KSKS process, and the upper limit at the 95% confidence level for its branching fraction is determined to be B(J/Psi -> KSKS) < 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.
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| 13. |
- Ablikim, M., et al.
(author)
-
Evidence for e+e−→γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:5
-
Journal article (peer-reviewed)abstract
- We present first evidence for the process e(+)e(-) -> 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(-) -> gamma eta(c)(1S)) = 2.11 +/- 0.49 (stat.) +/- 0.36 (syst.) pb with a statistical significance of 4.2 sigma.
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| 14. |
- Ablikim, M., et al.
(author)
-
First measurement of e(+)e(-) -> pK(S)(0)(n)over-barK(-) + c.c. above open charm threshold
- 2018
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 98:3
-
Journal article (peer-reviewed)abstract
- The process e(+)e(-) -> pK(S)(0)(n) over barK(-) + c.c. and its intermediate processes are studied for the first time, using data samples collected with the BESIII detector at BEPCII at center-of-mass energies of 3.773, 4.008, 4.226, 4.258, 4.358, 4.416, and 4.600 GeV, with a total integrated luminosity of 7.4 fb(-1). The Born cross section of e(+)e(-) -> pK(S)(0)(n) over barK(-) + c.c. is measured at each center-of-mass energy, but no significant resonant structure in the measured cross-section line shape between 3.773 and 4.600 GeV is observed. No evident structure is detected in the pK(-), nK(S)(0), pK(S)(0), nK(+), p (n) over bar, or (KSK-)-K-0 invariant mass distributions except for Lambda(1520). The Born cross sections of e(+)e(-) -> Lambda(1520)(n) over barK(S)(0) + c.c. and e(+)e(-) -> Lambda(1520)(p) over barK(+) + c.c. are measured, and the 90% confidence level upper limits on the Born cross sections of e(+)e(-) -> Lambda(1520)(Lambda) over bar (1520) are determined at the seven center-of-mass energies. There is an evident difference in line shape and magnitude of the measured cross sections between e(+)e(-) -> Lambda(1520)(-> pK(-))(n) over barK(S)(0) and e(+)e(-) -> pK-(Lambda) over bar (1520)(-> (n) over barK(S)(0)).
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| 15. |
- Ablikim, M., et al.
(author)
-
Improved measurements of two-photon widths of the chi(cJ) states and helicity analysis for chi(c2) -> gamma gamma
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:9
-
Journal article (peer-reviewed)abstract
- Based on 448.1 x 10(6) Psi(3686) events collected with the BESIII detector, the decays Psi(3686) -> gamma chi(cJ), chi(cJ) -> gamma gamma(J = 0, 1, 2) are studied. The decay branching fractions of chi(c0,2) -> gamma gamma are measured to be B(chi(c0) -> gamma gamma) = (1.93 +/- 0.08 +/- 0.05 +/- 0.05) x 10(-4) and B(chi(c2) -> 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) -> gamma chi(c0,2)) and the total widths Gamma(chi(c0,2)), respectively. For the forbidden decay of chi(c1) -> gamma gamma, no signal is observed, and an upper limit on the two-photon width is obtained to be Gamma(gamma gamma)(chi(c1)) < 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) -> 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.
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| 16. |
- Ablikim, M., et al.
(author)
-
Improved measurements of X-cJ -> Sigma(+) (Sigma)over-bar(-) and Sigma(0)(Sigma)over-bar(0) decays
- 2018
-
In: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:5
-
Journal article (peer-reviewed)abstract
- Using a data sample of (448.1 +/- 2.9) x 10(6) psi (3686) events collected with the BESIII detector at the BEPCII collider, we present measurements of branching fractions for the decays X-cJ -> Sigma(+) (Sigma) over bar (-) and Sigma(0) (Sigma) over bar (0) The decays X-c1.2 -> Sigma(+) (Sigma) over bar (-) and Sigma (Sigma) over bar (0) are observed for the first time, and the branching fractions for X-c0 -> Sigma(+) (Sigma) over bar (-) and Sigma(0) (Sigma) over bar (0) decays are measured with improved precision. The branching fraction ratios between the charged and neutral modes are consistent with the prediction of isospin symmetry.
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| 17. |
- Ablikim, M., et al.
(author)
-
Measurement of e(+)e(-) -> D(D)over-bar cross sections at the psi(3770) resonance
- 2018
-
In: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 42:8
-
Journal article (peer-reviewed)abstract
- We report new measurements of the cross sections for the production of D (D) over bar final states at the psi(3770) resonance. Our data sample consists of an integrated luminosity of 2.93 fb(-1) of e(+)e(-) annihilation data produced by the BEPCII collider and collected and analyzed with the BESIII detector. We exclusively reconstruct three D-0 and six D+ hadronic decay modes and use the ratio of the yield of fully reconstructed D (D) over bar events ("double tags") to the yield of all reconstructed D or (D) over bar mesons ("single tags") to determine the number of D-0(D) over bar (0) and D+D- events, benefiting from the cancellation of many systematic uncertainties. Combining these yields with an independent determination of the integrated luminosity of the data sample, we find the cross sections to be sigma(e(+)e(-) -> D-0(D) over bar (0)(-) )=(3.615 +/- 0.010 +/- 0.038) nb and sigma(e(+)e(-) -> D+D-)=(2.830 +/- 0.011 +/- 0.026) nb, where the uncertainties are statistical and systematic, respectively.
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| 18. |
- Ablikim, M., et al.
(author)
-
Measurement of the integrated Luminosities of cross-section scan data samples around the psi(3770) mass region
- 2018
-
In: Chinese Physics C. - : SCIENCE PRESS. - 1674-1137 .- 2058-6132. ; 42:6
-
Journal article (peer-reviewed)abstract
- To investigate the nature of the psi(3770) resonance and to measure the cross section for e(+)e(-) -> D (D) over bar, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16 +/- 0.04 +/- 0.61 pb(-1), where the first uncertainty is statistical and the second systematic.
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| 19. |
- Ablikim, M., et al.
(author)
-
Measurement of the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0)
- 2018
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:1
-
Journal article (peer-reviewed)abstract
- Based on a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector, the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) are determined using 351,016 eta' -> (eta -> gamma gamma)pi' pi(-) and 56,249 eta' -> (eta -> gamma gamma)pi(0) pi(0) events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in eta' -> eta pi(0)pi(0) is observed.
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| 20. |
- Ablikim, M., et al.
(author)
-
Measurements of the branching fractions for the semileptonic decays D-s(+) -> phi e(+)v(e), phi mu(+)v(mu), eta mu(+)v(mu) and eta 'mu(+)v(mu)
- 2018
-
In: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:1
-
Journal article (peer-reviewed)abstract
- By analyzing 482 pb(-1) of e(+) e(-) collision data collected at the center-of-mass energy root s = 4.009 GeV with the BESIII detector, we measure the branching fractions for the semi-leptonic decays D-s(+) -> phi e(+)v(e), phi mu(+)v(mu), eta mu(+)v(mu) and eta'mu(+)v(mu) to be B(D-s(+) -> phi e(+)v(e)) = (2.26 +/- 0.45 +/- 0.09)%, B(D-s(+) -> phi mu+v(mu)) = (1.94 +/- 0.53 +/- 0.09)%, B(D-s(+) -> eta mu(+)v(mu)) = (2.42 +/- 0.46 +/- 011)% and B(D-s(+) -> eta'mu(+)v(mu)) = (1.06 +/- 0.54 +/- 0.07)%, where the first and second uncertainties are statistical and systematic, respectively. The branching fractions for the three semi-muonic decays D-s(+) -> phi mu(+)v(mu), eta mu(+)v(mu) and eta'mu(+)v(mu) are determined for the first time and that of D-s(+) -> phi e(+)v(e) is consistent with the world average value within uncertainties.
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