31. |
- Ablikim, M., et al.
(författare)
-
Measurement of e(+)e(-) -> K(K)over-barJ/psi cross sections at center-of-mass energies from 4.189 to 4.600 GeV
- 2018
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:7
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the process e(+)e(-) -> K (K) over barJ/psi at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb(-1) of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions e(+)e(-) -> K(+)K(-)J/psi and K(S)(0)K(S)(0)J/psi are measured as a function of center-of-mass energy. The energy dependence of the cross section for e(+)e(-) -> K(+)K(-)J/psi is shown to differ from that for pi(+)pi(-)J/psi in the region around the Y(4260). In addition, there is evidence for a structure around 4.5 GeV in the e(+)e(-) -> K(+)K(-)J/psi cross section that is not present in pi(+)pi(-)J/psi.
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32. |
- Ablikim, M., et al.
(författare)
-
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
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:3
-
Tidskriftsartikel (refereegranskat)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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33. |
- Ablikim, M., et al.
(författare)
-
Measurement of e+e−→π0π0ψ(3686) at √s from 4.009 to 4.600 GeV and observation of a neutral charmoniumlike structure
- 2018
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 97:5
-
Tidskriftsartikel (refereegranskat)abstract
- Using ethorne-collision data collected with the BESIII detector at the BEPCII collider corresponding to an integrated luminosity of 5.2 fb(-1) at center-of-mass energies (root s) from 4.009 to 4.600 GeV, the process e(+)e(-) -> pi(0)pi(0)psi(3686) is studied for the first time. The corresponding Born cross sections are measured and found to be half of those of the reaction e(+)e(-) -> pi(0)pi(0)psi(3686). This is consistent with the expectation from isospin symmetry. Furthermore, the Dalitz plots for pi(0)pi(0)psi(3686) are accordant with those of pi(0)pi(0)psi(3686) at all energy points, and a neutral analog to the structure in pi(+/-)psi(3686) around 4040 MeV/c(2) first observed at root s = 4.416 GeV is observed in the isospin neutral mode at the same energy.
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34. |
- Ablikim, M., et al.
(författare)
-
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
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:7
-
Tidskriftsartikel (refereegranskat)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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35. |
- Ablikim, M., et al.
(författare)
-
Measurement of integrated luminosity and center-of-mass energy of data taken by BESIII at √s=2.125 GeV
- 2017
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:11
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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36. |
- Ablikim, M., et al.
(författare)
-
Measurement of Singly Cabibbo Suppressed Decays Lambda(+)(c) -> p pi(+)pi(-) and Lambda(+)(c) -> pK(+)K(-)
- 2016
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:23
-
Tidskriftsartikel (refereegranskat)abstract
- Using 567 pb(-1) of data collected with the BESIII detector at a center-of-mass energy of root s = 4.599 GeV, near the Lambda(+)(c)->(Lambda) over bar (-)(c) threshold, we study the singly Cabibbo-suppressed decays Lambda c(+) -> p pi(+) pi(-) and Lambda(+)(c) -> pK(+) K- By normalizing with respect to the Cabibbo-favored decay Lambda(+)(c)-> p pi(+)pi(-) we obtain ratios of branching fractions: [B(Lambda(+)(c) -> p pi(+)pi(-))/B(Lambda(+)(c) -> pK(-)pi(+))] = (6.70 +/- 0.48 +/- 0.25)% [B Lambda(+)(c) -> p phi)/B(Lambda(+)(c) -> pK(-)pi(+))] = (1.81 +/- 0.33 +/- 0.13)%,and [B(Lambda(+)(c) -> pK(+)K(non-phi)(-)/B(Lambda(+)(c) -> pK(-)pi(+))] (9.36 +/- 2.22 +/- 0.71)x10(-3), where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay Lambda(+)(c) -> p pi(+)pi(-) is observed for the first time, and the precision of the branching fraction for Lambda(+)(c) -> pK(+)K(non-phi)(-) and Lambda(+)(c) -> p phi is significantly improved.
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37. |
- Ablikim, M., et al.
(författare)
-
Measurement of the Absolute Branching Fraction for Lambda(+)(c) -> Lambda e(+)nu(e)
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:22
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda e(+)nu(e). This measurement is based on 567 pb(-1) of e(+)e(-) annihilation data produced at root s = 4.599 GeV, which is just above the Lambda(+)(c)Lambda(-)(c) threshold. The data were collected with the BESIII detector at the BEPCII storage rings. The branching fraction is determined to be B(Lambda(+)(c) -> Lambda e(+)nu(e)) = [3.63 +/- 0.38(stat) +/- 0.20(syst)] %, representing a significant improvement in precision over the current indirect determination. As the branching fraction for Lambda(+)(c) -> Lambda e(+)nu(e) is the benchmark for those of other Lambda(+)(c) semileptonic channels, our result provides a unique test of different theoretical models, which is the most stringent to date.
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38. |
- Ablikim, M., et al.
(författare)
-
Measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda mu(+)nu(mu)
- 2017
-
Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 767, s. 42-47
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda mu(+)nu(mu).This measurement is based on a sample of e+e(-) annihilation data produced at a center-of-mass energy root s = 4.6 GeV, collected with the BESIII detector at the BEPCII storage rings. The sample corresponds to an integrated luminosity of 567 pb(-1). The branching fraction is determined to be B( Lambda(+)(c) -> Lambda mu(+)nu(mu)) = (3.49 +/- 0.46( stat) +/- 0.27( syst))%. In addition, we calculate the ratio B( Lambda(+)(c) -> Lambda mu(+)nu(mu))/B(Lambda(+)(c) -> Lambda e(+)nu(e) to be 0.96 +/- 0.16( stat) +/- 0.04( syst).
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39. |
- Ablikim, M., et al.
(författare)
-
Measurement of the absolute branching fraction of D+ → K̅0 e+νe via K̅0 → π 0 π 0
- 2016
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:11
-
Tidskriftsartikel (refereegranskat)abstract
- By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..
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40. |
- Ablikim, M., et al.
(författare)
-
Measurement of the absolute branching fraction of D*(s0) (2317)(+/-) -> pi D-0(s)+/-
- 2018
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 97:5
-
Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> D*D-+(s)*(s0) (2317)(-) + c.c. is observed for the first time with the data sample of 567 pb(-1) collected with the BESIII detector operating at the BEPCII collider at a center-of-mass energy root s = 4.6 GeV. The statistical significance of the D*(s0) (2317)(+/-) signal is 5.8 sigma and the mass is measured to be (2318.3 +/- 1.2 +/- 1.2) MeV/c(2). The absolute branching fraction B(D*(s0) (2317)(+/-) -> pi D-0(s)+/-) is measured as 1.00(-0.14)(+0.00) (stat)(-0.14)(+0.00) (syst) for the first time. The uncertainties are statistical and systematic, respectively.
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