| 31. |
- Ablikim, M., et al.
(författare)
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Measurement of the leptonic decay width of J/psi using initial state radiation
- 2016
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 761, s. 98-103
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Tidskriftsartikel (refereegranskat)abstract
- Using a data set of 2.93 fb(-1) taken at a center-of-mass energy of root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we measure the process e(+) e(-) -> J/psi gamma -> mu(+)mu(-)gamma and determine the product of the branching fraction and the electronic width B-mu mu . Gamma(ee) = (333.4 +/- 2.5(stat) +/- 4.4(sys)) eV. Using the earlier-published BESIII result for B-mu mu = (5.973 +/- 0.007(stat) +/- 0.037(sys))%, we derive the J/psi electronic width Gamma(ee) = (5.58 +/- 0.05(stat) +/- 0.08(sys)) keV. (C) 2016 The Author(s). Published by Elsevier B.V.
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| 32. |
- Ablikim, M., et al.
(författare)
-
Measurement of the matrix elements for the decays eta -> pi(+)pi(-)pi(0) and eta/eta ' -> pi(0)pi(0)pi(0)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:1
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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 at the BEPCII collider, Dalitz plot analyses of selected 79,625 eta -> pi(+)pi(-)pi(0) events, 33,908 eta -> pi(0)pi(0)pi(0) events, and 1,888 eta' -> pi(0)pi(0)pi(0) events are performed. The measured matrix elements of eta -> pi(+)pi(-)pi(0) are in reasonable agreement with previous measurements. The Dalitz plot slope parameters of eta -> pi(0)pi(0)pi(0) and eta' -> pi(0)pi(0)pi(0) are determined to be -0.055 +/- 0.014 +/- 0.004 and -0.640 +/- 0.046 +/- 0.047, respectively, where the first uncertainties are statistical and the second systematic. Both values are consistent with previous measurements, while the precision of the latter one is improved by a factor of 3. Final state interactions are found to have an important role in those decays.
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| 33. |
- Ablikim, M., et al.
(författare)
-
Measurements of the absolute branching fractions for D-s(+) -> eta e(+)nu(e) and D-s(+) -> eta ' e(+)nu(e)
- 2016
-
Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:11
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Tidskriftsartikel (refereegranskat)abstract
- By analyzing 482 pb(-1) of e(+)e(-) collision data collected at root s = 4.009 GeV with the BESIII detector at the BEPCII collider, we measure the absolute branching fractions for the semileptonic decays D-s(+) -> eta e(+)nu(e) and D-s(+) -> eta ' e(+)nu(e) to be B(D-s(+) -> eta e(+)nu(e)) = (2.30 +/- 0.31 +/- 0.08)% and B(D-s(+) -> eta ' e(+)nu(e)) = (0.93 +/- 0.30 +/- 0.05)%, respectively, and their ratio B(D-s(+) -> eta ' e(+)nu(e)) / B(D-s(+) -> eta ' e(+)nu(e)) = 0.40 +/- 0.14 +/- 0.02, where the first uncertainties are statistical and the second ones are systematic. The results are in good agreement with previous measurements within uncertainties; they can be used to determine the eta-eta' mixing angle and improve upon the D-s(+) semileptonic branching ratio precision.
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| 34. |
- Ablikim, M., et al.
(författare)
-
Observation and Spin-Parity Determination of the X(1835) in J/psi -> gamma(KSKS0)-K-0 eta
- 2015
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:9
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Tidskriftsartikel (refereegranskat)abstract
- We report an observation of the process J/psi -> gamma X(1835) -> gamma(KSKS0)-K-0 eta at low (KSKS0)-K-0 mass with a statistical significance larger than 12.9s using a data sample of 1.31 x 109 J/psi events collected with the BESIII detector. In this region of phase space the (KSKS0)-K-0 system is dominantly produced through the f (0)(980). By performing a partial wave analysis, we determine the spin parity of the Xd1835_ to be J(PC) = 0(-+). The mass and width of the observed X(1835) are 1844 +/- 9(stat)(-25)(+16)(syst) MeV/c(2) and 192(-17)(+20)(sta)(-43)(+62)(syst) MeV, respectively, which are consistent with the results obtained by BESIII in the channel J/psi -> gamma pi(+)pi(-)eta'.
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| 35. |
- Ablikim, M., et al.
(författare)
-
Observation of a cross-section enhancement near mass threshold in e(+)e(-) -> Lambda(Lambda)over-bar
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:3
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Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> Lambda(Lambda) over bar is studied using data samples at root s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is measured at root s = 2.2324 GeV, which is 1.0 MeVabove the Lambda(Lambda) over bar mass threshold, to be 305 +/- 45(-36)(+66) pb, where the first uncertainty is statistical and the second systematic. The cross section near threshold is larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at root s = 2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Lambda are deduced.
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| 36. |
- Ablikim, M., et al.
(författare)
-
Observation of a Neutral Charmoniumlike State Z(c)(4025)(0) in e(+)e(-) -> (D*(D)over-bar*)(0)pi(0)
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:18
-
Tidskriftsartikel (refereegranskat)abstract
- We report a study of the process e(+)e(-) -> (D*(D) over bar*)(0)pi(0) using e(+)e(-) collision data samples with integrated luminosities of 1092 pb(-1) at root s = 4.23 GeV and 826 pb(-1) at root s = 4.26 GeV collected with the BESIII detector at the BEPCII storage ring. We observe a new neutral structure near the (D*(D) over bar*)(0) mass threshold in the pi(0) recoil mass spectrum, which we denote as Z(c)(4025)(0). Assuming a Breit-Wigner line shape, its pole mass and pole width are determined to be (4025.5(-4.7)(+2.0) +/- 3.1) MeV/c(2) and (23.0 +/- 6.0 +/- 1.0) MeV, respectively. The Born cross sections of e(+)e(-) -> Z(c)(4025)(0)pi(0) -> (D*(D) over bar*)(0)pi(0) are measured to be (61.6 +/- 8.2 +/- 9.0) pb at root s = 4.23 GeV and (43.4 +/- 8.0 +/- 5.4) pb at root s = 4.26 GeV. The first uncertainties are statistical and the second are systematic.
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| 37. |
- Ablikim, M., et al.
(författare)
-
Observation of a Neutral Structure near the D(D)over-bar* Mass Threshold in e(+)e(-) -> (D(D)over-bar*)(0)pi(0) at root s=4.226 and 4.257 GeV
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:22
-
Tidskriftsartikel (refereegranskat)abstract
- A neutral structure in the D (D) over bar* system around the D (D) over bar* mass threshold is observed with a statistical significance greater than 10 sigma in the processes e(+)e(-) -> D+D*(-)pi(0) + c.c. and e(+)e(-) -> D-0(D) over bar*(0)pi(0) + c.c. at root s = 4.226 and 4.257 GeV in the BESIII experiment. The structure is denoted as Z(c)(3885)(0). Assuming the presence of a resonance, its pole mass and width are determined to be [3885.7(-5.7)(+4.3) (stat) +/- 8.4(syst)] MeV/c(2) and [35(-12)(+11) (stat) +/- 15(syst)] MeV, respectively. The Born cross sections are measured to be sigma[e(+)e(-) -> Z(c)(3885)(0)pi(0); Z(c)(3885)(0) -> D (D) over bar*] = [77 +/- 13(stat) +/- 17(syst)] pb at 4.226 GeV and [47 +/- 9(stat) +/- 10(syst)] pb at 4.257 GeV. The ratio of decay rates B[Z(c)(3885)(0) -> D+D*(-) + c.c.]/B[Z(c)(3885)(0) -> D-0(D) over bar*(0) + c.c.] is determined to be 0.96 +/- 0.18(stat) +/- 0.12(syst), consistent with no isospin violation in the process, Z(c)(3885)(0) -> D (D) over bar*.
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| 38. |
- Ablikim, M., et al.
(författare)
-
Observation of e(+)e(-) -> eta h(c) at center-of-mass energies from 4.085 to 4.600 GeV
- 2017
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:1
-
Tidskriftsartikel (refereegranskat)abstract
- We observe for the first time the process e(+) e(-) -> eta h(c) with data collected by the BESIII experiment. Significant signals are observed at the center-of-mass energy root s = 4.226 GeV, and the Born cross section is measured to be (9.5(-2.0)(+2.2)) pb. Evidence for eta h(c) is observed at root s = 4.358 GeV with a Born cross section of (10.0(-2.7)(+3.1)) pb, and upper limits on the production cross section at other center-of-mass energies between 4.085 and 4.600 GeV are determined.
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| 39. |
- Ablikim, M., et al.
(författare)
-
Observation of Lambda(+)(c) -> nK(S)(0)pi(+)
- 2017
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 118:11
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first direct measurement of decays of the Lambda(+)(c) baryon involving the neutron. The analysis is performed using 567 pb(-1) of e(+)e(-) collision data collected at root s = 4.599 GeV with the BESIII detector at the BEPCII collider. We observe the decay Lambda(+)(c) -> nK(S)(0)pi(+) and measure the absolute branching fraction to be B(Lambda(+)(c) -> nK(S)(0)pi(+)) = [1.82 +/- 0.23(stat) +/- 0.11(syst)]%. A comparison to B[Lambda(+)(c) -> p( (K) over bar pi)(0)] provides an important test of isospin symmetry and final state interactions.
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| 40. |
- Ablikim, M., et al.
(författare)
-
Observation of the helicity-selection-rule suppressed decay of the χc2 charmonium state
- 2017
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 96:11
-
Tidskriftsartikel (refereegranskat)abstract
- The decays of chi(c2) -> K+K- pi(0), KSK +/-pi(-/+), and pi(+)pi(-)pi(0) are studied with the psi(3686) data samples collected with the Beijing Spectrometer ( BESIII). For the first time, the branching fractions of chi(c2) -> K*(K) over bar,chi(c2) -> a(2)(+/-)(1320)pi(-/+)/a(2)(0)(1320)pi(0), and chi(c2) -> rho(770)(+/-)pi(-/+) are measured. Here, K*(K) over bar denotes both K*K-+/-(-/+) and its isospin-conjugated process K*(0)(K) over bar (0) + c: c:, and K* denotes the resonances K*(892), K*(2)(1430), and K*(3)(1780). The observations indicate a strong violation of the helicity selection rule in chi(c2) decays into vector and pseudoscalar meson pairs. The measured branching fractions of chi(c2) -> K*(892)(K) over bar are more than ten times larger than the upper limit of chi(c2) -> rho(770)(+/-)pi(-/+), which is so far the first direct observation of a significant U-spin symmetry breaking effect in charmonium decays.
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