| 11. |
- Ablikim, M., et al.
(författare)
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Search for the rare decays D -> h(h((')))e(+) e(-)
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:7
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Tidskriftsartikel (refereegranskat)abstract
- We search for rare decays of D mesons to hadrons accompanied by an electron-positron pair (h(h((')))e(+)e(- )),using an e(+)e(-) collision sample corresponding to an integrated luminosity of 2.93 fb(-1) collected with the BESIII detector at root s = 3.773 GeV. No significant signals are observed, and the corresponding upper limits on the branching fractions at the 90% confidence level are determined. The sensitivities of the results are at the level of 10(-5)-10(-6), providing a large improvement over previous searches.
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| 12. |
- Ablikim, M., et al.
(författare)
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Study of two-photon decays of pseudoscalar mesons via J/Psi radiative decays
- 2018
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 97:7
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Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 4.48 x 10(8) Psi(3686) events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons pi(0,) eta , eta' , eta(1405), eta(1475), eta(1760), and X(1835) in J/Psi radiative decays using Psi(3686) -> pi(+) pi(-) J/Psi events. The pi(0), eta, and eta' mesons are clearly observed in the two-photon mass spectra, and the branching fractions are determined to be B(J/Psi -> gamma pi(0) -> 3 gamma) = (3.57 +/- 0.12 +/- 0.16) x 10(-5), B(J/Psi -> gamma eta -> 3 gamma) = (4.42 +/- 0.04 +/- 0.18) x 10(-4), and B(J/Psi -> gamma eta' -> 2 gamma) = (1.26 +/- 0.02 +/- 0.05) x 10(-4), where the first error is statistical and the second is systematic. No clear signal for eta(1405), eta(1475), eta(1760) or X(1835) is observed in the two- photon mass spectra, and upper limits at the 90% confidence level on the product branching fractions are obtained.
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| 13. |
- Ablikim, M., et al.
(författare)
-
Measurement of the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0)
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:1
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Tidskriftsartikel (refereegranskat)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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| 14. |
- Ablikim, M., et al.
(författare)
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Measurements of absolute branching fractions for D mesons decays into two pseudoscalar mesons
- 2018
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:7
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of e(+)e(-) collision data with an integrated luminosity of 2.93 fb(-1) taken at the center-of-mass energy root s = 3.773 GeV with the BESIII detector operating at the BEPCII storage rings, we measure the absolute branching fractions of the two-body hadronic decays D+ -> pi(+)pi(0), K+pi(0), pi(+)eta., K+eta., pi(+)eta', K+eta', K-S(0)pi(+), (KSK+)-K-0, and D-0 -> pi(+)pi(-), K+ K-, K--/+pi(+/-), K-S(0)pi(0), K-S(0)eta, K-S(0)eta' Our results are consistent with previous measurements within uncertainties. Among them, the branching fractions for D+-> pi(+)pi(0), K+pi(0), pi(+)eta, pi(+)eta', (KSK+)-K-0, (KSK+)-K-0 and D-0 -> K-S(0)pi(0), K-S(0)eta, K-S(0)eta' are determined with improved precision compared to the world average values.
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| 15. |
- Ablikim, M., et al.
(författare)
-
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
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:1
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Tidskriftsartikel (refereegranskat)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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| 16. |
- Ablikim, M., et al.
(författare)
-
Observation of e(+)e(-) -> phi chi(c1) and phi chi(c2) at root s=4.600 GeV
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of root s = 4.600 GeV, we search for the production of e(+)e(-) -> phi chi(c0,1,2). A search is also performed for the charmonium-like state X(4140) in the radiative transition e(+)e(-) -> gamma X(4140) with X(4140) subsequently decaying into phi J/psi The processes e(+)e(-) -> phi chi(c1) and phi chi(c2) are observed for the first time, each with a statistical significance of more than 10 sigma, and the Born cross sections are measured to be (4.2(-1.0)(+1.7) +/- 0.3) and (6.7(-1.7)(+3.4) +/- 0.5) pb, respectively, where the first uncertainties are statistical and the second systematic. No significant signals are observed for e(+)e(-) -> phi chi(c0) and e(+)e(-) -> gamma X(4140) and upper limits on the Born cross sections at 90% C. L. are provided at root s = 4.600 GeV.
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| 17. |
- 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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| 18. |
- Ablikim, M., et al.
(författare)
-
Precision Measurement of the e(+)e(-) -> Lambda(+)(c)(Lambda)over-bar(c)(-) Cross Section Near Threshold
- 2018
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 120:13
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Tidskriftsartikel (refereegranskat)abstract
- The cross section of the e(+)e(-) -> Lambda(+)(c)(Lambda) over bar (-)(c) process is measured with unprecedented precision using data collected with the BESIII detector at root s = 4574.5, 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross section near the Lambda(+)(c)(Lambda) over bar (-)(c) production threshold is cleared. At center-of-mass energies root s = 4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Lambda(c) polar angle distributions. From these, the.c electric over magnetic form-factor ratios (vertical bar G(E)/G(M)vertical bar) are measured for the first time. They are found to be 1.14 +/- 0.14 +/- 0.07 and 1.23 +/- 0.05 +/- 0.03, respectively, where the first uncertainties are statistical and the second are systematic.
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| 19. |
- Ablikim, M., et al.
(författare)
-
Search for the rare decay of ψ(3686)→Λ+c¯pe+e−+c.c. at BESIII
- 2018
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 97:9
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Tidskriftsartikel (refereegranskat)abstract
- Based on a data sample of (448.1 +/- 2.9) x 10(6)Psi(3686) decays collected with the BESIII experiment, a search for the flavor changing neutral current transition Psi(3686) -> Lambda(+)(c) pe(+) e(-) + c.c. is performed for the first time. No signal candidates are observed and the upper limit on the branching fraction of Psi(3686) -> Lambda(+)(c) pe(+) e(-) is determined to be 1.7 x 10(-6) at the 90% confidence level. The result is consistent with expectations from the standard model, and no evidence for new physics is found.
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| 20. |
- Ablikim, M., et al.
(författare)
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Amplitude analysis of the KSKS system produced in radiative J /psi decays
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 98:7
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Tidskriftsartikel (refereegranskat)abstract
- An amplitude analysis of the KSKS system produced in radiative J/psi decays is performed using the (1310.6 +/- 7.0) x 10(6) nip decays collected by the BESIII detector. Two approaches are presented. A mass-dependent analysis is performed by parametrizing the KSKS invariant mass spectrum as a sum of Breit-aligner line shapes. Additionally, a mass-independent analysis is performed to extract a piecewise function that describes the dynamics of the KSKS system while making minimal assumptions about the properties and number of poles in the amplitude. The dominant amplitudes in the mass-dependent analysis include the f(0)(1710), f(0)(2200), and f(2)'(1525). The mass-independent results, which are made available as input for further studies, are consistent with those of the mass-dependent analysis and are useful for a systematic study of hadronic interactions. The branching fraction of radiative J/psi decays to KSKS is measured to be (8.1 +/- 0.4) x 10(-4), where the uncertainty is systematic and the statistical uncertainty is negligible.
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