| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- Ablikim, M., et al.
(author)
-
Measurement of branching fractions for psi(3686) -> gamma eta ', gamma eta, and gamma pi(0)
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:5
-
Journal article (peer-reviewed)abstract
- 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) -> gamma eta and psi(3686) -> 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) -> gamma eta) = (0.85 +/- 0.18 +/- 0.05) x 10(-6) and B(psi(3686) ->gamma pi(0)) = (0.95 +/- 0.16 +/- 0.05) x 10(-6). In addition, we measure the branching fraction of psi(3686) -> gamma eta' to be B(psi(3686) -> gamma eta') = (125.1 +/- 2.2 +/- 6.2)x10(-6), which represents an improvement of precision over previous results.
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| 5. |
- Ablikim, M., et al.
(author)
-
Observation of χc2→η′η′ and χc0,2→ηη′
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:11
-
Journal article (peer-reviewed)abstract
- Using a sample of 448.1×106 ψ(3686) events collected with the BESIII detector in 2009 and 2012, we study the decays χc0,2→η′η′ and ηη′. The decays χc2→η′η′, χc0→ηη′ and χc2→ηη′ are observed for the first time with statistical significances of 9.6σ, 13.4σ and 7.5σ, respectively. The branching fractions are determined to be B(χc0→η′η′)=(2.19±0.03±0.14)×10−3, B(χc2→η′η′)=(4.76±0.56±0.38)×10−5, B(χc0→ηη′)=(8.92±0.84±0.65)×10−5 and B(χc2→ηη′)=(2.27±0.43±0.25)×10−5, where the first uncertainties are statistical and the second are systematic. The precision for the measurement of B(χc0→η′η′) is significantly improved compared to previous measurements. Based on the measured branching fractions, the role played by the doubly and singly Okubo-Zweig-Iizuka disconnected transition amplitudes for χc0,2 decays into pseudoscalar meson pairs can be clarified.
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| 6. |
- Ablikim, M., et al.
(author)
-
Study of J/ψ and ψ(3686) decays to π+π−η′
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:11
-
Journal article (peer-reviewed)abstract
- Using the data samples of 1.31×109 J/ψ events and 4.48×108 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))×10−5. 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))×10−5 for the case of destructive interference, and (5.69±1.28(stat)±2.36(sys))×10−6 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))×10−4 and (1.51±0.14(stat)±0.23(sys))×10−5, respectively
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| 7. |
- Ablikim, M., et al.
(author)
-
Study of J/ψ and ψ(3686) decay to Λ¯Λ and Σ0¯Σ0 final states
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 95:5
-
Journal article (peer-reviewed)abstract
- 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 -> Lambda(Lambda) over bar -> Sigma(0)(Sigma) over tilde (0) , psi (3686) -> Lambda(Lambda) over bar and psi (3686) -> 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)->Lambda(Lambda) over bar)/B(J/psi -> Lambda(Lambda) over bar) and B(psi(3686)->Sigma(0)(Sigma) over tilde (0))/B(J/psi ->Sigma(0)(Sigma) over tilde (0)) are determined to test the "12% rule."
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| 8. |
- Ablikim, M., et al.
(author)
-
Branching fraction measurements of psi (3686) -> gamma chi(cJ)
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:3
-
Journal article (peer-reviewed)abstract
- Using a sample of 106 million psi(3686) decays, the branching fractions of psi(3686) -> gamma chi(c0), psi(3686) -> gamma chi(c1), and psi(3686) -> 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) -> gamma chi(c1), chi(c1) -> gamma J/psi (3686) -> gamma chi(c2), chi(c2) -> gamma J/psi and the branching fractions of chi(c1) -> gamma J/psi and chi(c2) -> gamma J/psi are also presented.
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| 9. |
- Ablikim, M., et al.
(author)
-
Observation of the decay Lambda(+)(c) -> Sigma(-)pi(+)pi(+)pi(0)
- 2017
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 772, s. 388-393
-
Journal article (peer-reviewed)abstract
- We report the first observation of the decay Lambda(+)(c) -> 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) -> 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) -> Sigma(-)pi(+)pi(+)pi(0)) is determined as (1.81 +/- 0.17(stat.) +/- 0.09(syst.))%.
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| 10. |
- Ablikim, M., et al.
(author)
-
Search for the rare decays J/ψ→D0e+e−+c.c. and ψ(3686)→D0e+e−+c.c.
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:11
-
Journal article (peer-reviewed)abstract
- 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 -> D(0)e(+) e(-) + c.c. and psi(3686) -> 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 -> D(0)e(+) e(-) + c.c.) < 8.5 x 10(-8) and B(psi(3686) -> D(0)e(+) e(-) + c.c.) < 1.4 x 10(-7), respectively. Our limit on B(J/psi -> D(0)e(+) e(-) + c.c.) is more stringent by 2 orders of magnitude than the previous results, and B(psi(3686) -> D(0)e(+) e(-) + c.c.) is measured for the first time.
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| 11. |
- Ablikim, M., et al.
(author)
-
Search for ψ(3686)→γηc(η(1405))→γπ+π−π0
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:11
-
Journal article (peer-reviewed)abstract
- Using a sample of 448.1×106 ψ(3686) events collected with the BESIII detector, a search for the isospin violating decay ηc→π+π−π0 via ψ(3686)→γηc is presented. No signal is observed, and the upper limit on B(ψ(3686)→γηc)×B(ηc→π+π−π0) is determined to be 1.6×10−6 at the 90% confidence level. In addition, a search for η(1405)→f0(980)π0 in ψ(3686) radiative decays is performed. No signal is observed, and the branching fraction B(ψ(3686)→γη(1405))×B(η(1405)→f0(980)π0)×B(f0(980)→π+π−) is calculated to be less than 5.0×10−7 at the 90% confidence level.
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| 12. |
- Ablikim, M., et al.
(author)
-
Amplitude analysis of D0 → K -π+π+π-
- 2017
-
In: Physical Review D. - 2470-0010 .- 2470-0029. ; 95:7
-
Journal article (peer-reviewed)abstract
- We present an amplitude analysis of the decay D0 → K -π+π+π- based on a data sample of 2.93 fb−1 acquired by the BESIII detector at the ψ(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 D0 → ¯K*0ρ0, D0 → K−a+1(1260) and D0 → K−1(1270)π+, the three-body decays D0 →¯K*0π+π− and D0 → K−π+ρ0, as well as the four-body nonresonant decay D0 → K−π+π+π−. The dominant intermediate process is D0 → K−a+1(1260), accounting for a fit fraction of 54.6%.
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| 13. |
- Ablikim, M., et al.
(author)
-
Amplitude analysis of the chi(c1) -> eta pi(+)pi(-) decays
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3
-
Journal article (peer-reviewed)abstract
- Using 448.0 x 10(6) psi(3686) events collected with the BESIII detector, an amplitude analysis is performed for psi(3686) -> gamma chi(c1), chi(c1) ->eta pi(+)pi(-) decays. The most dominant two- body structure observed is a(0)(980)(+/-) pi(-/+); a(0)(980)(+/-) -> 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) -> 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) -> pi(1)(1400)(+/-)pi(-/+) , chi(c1) -> pi(1)(1600)(+/-)pi(-/+) and chi(c1) -> pi 1(2015)(+/-)pi(-/+) with subsequent pi(1)(X)(+/-) -> eta pi(+/-) decay, are determined.
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| 14. |
- Ablikim, M., et al.
(author)
-
Amplitude Analysis of the Decays eta ' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0)
- 2017
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 118:1
-
Journal article (peer-reviewed)abstract
- Based on a sample of 1.31 x 10(9) J/Psi events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays eta' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0) is performed. A significant P-wave contribution from eta' -> rho(+/-)eta(-/+) is observed for the first time in eta' -> pi(+)pi(-)pi(0). The branching fraction is determined to be B(eta' -> rho(+/-)pi(-/+)) = (7.44 +/- 0.60 +/- 1.26 +/- 1.84) x 10(-4), where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant S-wave component, there is a significant sigma meson component. The branching fractions of the combined S-wave components are determined to be B(eta' -> pi(+)pi(-)pi(0))(S) = (37.63 +/- 0.77 +/- 2.22 +/- 4.48) x 10(-4) and B(eta' -> pi(0)pi(0)pi(0)) = (35.22 +/- 0.82 +/- 2.54) x 10(-4), respectively. The latter one is consistent with previous BESIII measurements.
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| 15. |
- Ablikim, M., et al.
(author)
-
Analysis of D+ -> (K)over-bar(0)e(+)nu(e) and D+ -> pi(0)e(+)nu(e) semileptonic decays
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:1
-
Journal article (peer-reviewed)abstract
- 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+ -> (K) over bar (0)e(+)nu(e) and D+ -> pi(0)e(+)nu(e). We measure the absolute decay branching fractions B(D+ -> (K) over bar (0)e(+)nu(e)) = (8.60 +/- 0.06 +/- 0.15) x 10(-2) and B(D+ -> 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.
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| 16. |
- Ablikim, M., et al.
(author)
-
Dark photon search in the mass range between 1.5 and 3.4 GeV/c
- 2017
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 252-257
-
Journal article (peer-reviewed)abstract
- Using a data set of 2.93 fb taken at a center-of-mass energy root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions e(+)e(-) -> e(+)e(-) gamma(ISR) and e(+)e(-) -> mu(+)mu(-) gamma(ISR) for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c(2) and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
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| 17. |
- Ablikim, M., et al.
(author)
-
Determination of the number of J/psi events with inclusive J/psi decays
- 2017
-
In: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:1
-
Journal article (peer-reviewed)abstract
- A measurement of the number of J/psi events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the J/psi. The number of J/psi events taken in 2009 is recalculated to be (223.7 +/- 1.4) x 10(6), which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of J/psi events taken in 2012 is determined to be (1086.9 +/- 6.0) x 10(6). In total, the number of J/psi events collected with the BESIII detector is measured to be (1310.6 +/- 7.0) x 10(6), where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.
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| 18. |
- Ablikim, M., et al.
(author)
-
Determination of the Spin and Parity of the Z(c)(3900)
- 2017
-
In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 119:7
-
Journal article (peer-reviewed)abstract
- 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(-) -> 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(-) -> Z(c)(3900)(+)pi(-) + c.c. -> J/psi pi(+)pi(-) and determine an upper limit at the 90% confidence level for the process e(+)e(-) -> Z(c)(4020)(+)pi(-) + c.c. -> J/psi pi(+)pi(-).
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| 19. |
- Ablikim, M., et al.
(author)
-
Evidence for the singly Cabibbo suppressed decay Lambda(+)(c) -> p eta and search for Lambda(+)(c) -> p pi(0)
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:11
-
Journal article (peer-reviewed)abstract
- We study the singly Cabibbo suppressed decays Lambda(+)(c) -> p eta and Lambda(+)(c) -> 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) -> p eta with a statistical significance of 4.2 sigma and measure its branching fraction to be B(Lambda(+)(c) -> p eta) = (1.24 +/- 0.28(stat) +/- 0.10(sys)) x 10(-3). No significant Lambda(+)(c) -> p pi(0) signal is observed. We set an upper limit on its branching fraction B(Lambda(+)(c) -> p pi(0)) < 2.7 x 10(-4) at the 90% confidence level.
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| 20. |
- Ablikim, M., et al.
(author)
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Evidence of Two Resonant Structures in e(+)e(-)->pi(+) pi(-) h(c)
- 2017
-
In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 118:9
-
Journal article (peer-reviewed)abstract
- The cross sections of e(+)e(-) -> 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(-) -> pi(+) pi(-) J/psi and e(+)e(-) -> 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(-) -> 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.
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| 21. |
- Ablikim, M., et al.
(author)
-
Improved measurements of branching fractions for eta(c) -> phi phi and omega phi
- 2017
-
In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:9
-
Journal article (peer-reviewed)abstract
- 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) -> phi phi is measured to be Br(eta(c) -> 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 -> gamma eta(C)). No significant signal for the double Okubo-Zweig-Iizuka suppressed decay of eta(c) -> omega phi is observed, and the upper limit on the branching fraction is determined to be Br(eta(c) -> omega phi) < 2.5 x 10(-4) at the 90% confidence level.
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| 22. |
- Ablikim, M., et al.
(author)
-
Luminosity measurements for the R scan experiment at BESIII
- 2017
-
In: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:6
-
Journal article (peer-reviewed)abstract
- By analyzing the large-angle Bhabha scattering events e+e- → (γ)e+e- and diphoton events e+e- → (γ)γγ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900 GeV (131 energy points in total) with the upgraded Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPCII), the integrated luminosities have been measured at the different c.m. energies, individually. The results are important inputs for the R value and J/ψ resonance parameter measurements.
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| 23. |
- Ablikim, M., et al.
(author)
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Measurement of cross sections of the interactions e(+)e(-) -> phi phi omega and e(+)e(-) -> phi phi phi at center-of-mass energies from 4.008 to 4.600 GeV
- 2017
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 78-86
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Journal article (peer-reviewed)abstract
- 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(-) -> phi phi omega and e(-)e(-) -> phi phi phi. The Born cross sections are measured and the ratio of the cross sections sigma(e(+)e(-) -> phi phi omega)/sigma(e(-)e(-) -> 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.
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| 24. |
- Ablikim, M., et al.
(author)
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Measurement of e(+)e(-) -> 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
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:3
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Journal article (peer-reviewed)abstract
- We study the process e(+)e(-) -> 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(-) -> 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(-) -> 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.
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| 25. |
- Ablikim, M., et al.
(author)
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Measurement of higher-order multipole amplitudes in psi(3686) -> gamma chi(c1,2) with chi(c1,2) -> gamma J/psi and search for the transition eta(c)(2S) -> gamma J/psi
- 2017
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In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:7
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Journal article (peer-reviewed)abstract
- Using 106 x 10(6) psi(3686) events collected with the BESIII detector, we measure multipole amplitudes for the decay psi(3686) ->; gamma chi(c1,2) -> gamma gamma J/psi beyond the dominant electric-dipole amplitudes. The normalized magnetic-quadrupole (M2) amplitude for psi(3686) -> gamma chi(c1,2) -> gamma gamma J/psi and the normalized electric-dipole amplitudes for psi(3686) -> gamma chi(c2) -> gamma J/psi and determined. The M2 amplitudes for psi(3686) -> gamma chi(c1) and ; chi(c1,2) -> gamma J/psi are found to differ significantly from zero and are consistent with theoretical predictions. We also obtain the ratios of M2 contributions of psi(3686) and J/psi decays to;2,chi(c1,2,) b(2)(1/)b(2)(2) = 1.35 +/- 0.72 and a(2)(1/)a(2)(2) = 0.617 +/- 0.083,,which agree well with theoretical expectations. By considering the multipole contributions of chi(c1,2), we measure the product branching fractions for the cascade decays psi(3686) -> gamma chi(c 0,1,2) -> gamma gamma J/psi and search for the process eta(c)(2s) -> gamma J/psi through psi(3686) -> gamma eta(c)(2s).The product branching fraction for psi(3686) -> gamma chi(c0) -> gamma gamma J/psi is 3 sigma larger than published measurements, while those of psi(3686) -> gamma chi(c1,2) -> gamma gamma J/psi are consistent. No significant signal for the decay psi(3686) -> gamma eta(c) (2s) -> gamma gamma J/psi is observed, and the upper limit of the product branching fraction at the 90% confidence level is determined.
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