| 1. |
- Ablikim, M., et al.
(författare)
-
Observation of a near-threshold enhancement in the Λλ mass spectrum from e+e- → Φ Λλ at √s is from 3.51 to 4.60 GeV
- 2021
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:5
-
Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> phi Lambda(Lambda) over bar is studied using data samples collected with the BESIII detector at the BEPCII Collider at center of mass energies root S ranging from 3.51 GeV to 4.60 GeV. An enhancement is observed near the threshold of Lambda(Lambda) over bar. The lineshape of this enhancement is studied in different approaches, including fit with a Breit-Wiper function or a reversed exponential function. The Breit-Wigner function has a mass of (2262 +/- 4 +/- 28) McV/c(2) and a width of (72 +/- 5 +/- 43) MeV, where the quoted uncertainties are statistical and systematic, respectively. The rising rate of the reversed exponential function is measured as 33 +/- 11 +/- 6 MeV/c(2). For the Lambda(Lambda) over bar system, the J(PC) quantum numbers of 0(-+) and 0(+)(+) are rejected, while other J(PC) hypotheses are possible, according to the helicity-angle study. The energy-dependent cross section of the e(+)e(-) -> phi Lambda(Lambda) over bar process is measured for the first time in this energy region, and contributions from excited psi states and vector charmoniumlike Y-states are investigated.
|
|
| 2. |
- Ablikim, M., et al.
(författare)
-
Amplitude analysis of the KSKS system produced in radiative J /psi decays
- 2018
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 98:7
-
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.
|
|
| 3. |
- Ablikim, M., et al.
(författare)
-
Determination of the Λ+c spin via the reaction e+e− → Λc¯Λc
- 2021
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:9
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a comparison of two possible Λ+c spin hypotheses, J=½ and 3/2, via the process e+e− → Λ+c¯Λ−c, using the angular distributions of Λ+c decays into pK0S, Λπ+, Σ0π+, and Σ+π0. The data were recorded at √s=4.6 GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb−1. The Λ+c spin is determined to be J=½, with this value favored over the 3/2 hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
|
|
| 4. |
- Ablikim, M., et al.
(författare)
-
Luminosities and energies of e+e− collision data taken between √s=4.61 GeV and 4.95 GeV at BESIII
- 2022
-
Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
-
Tidskriftsartikel (refereegranskat)abstract
- From December 2019 to June 2021, the BESIII experiment collected approximately 5.85 fb−1 of data at center-of-mass energies between 4.61 and 4.95 GeV. This is the highest collision energy BEPCII has reached to date. The accumulated annihilation data samples are useful for studying charmonium(-like) states and charmed-hadron decays. By adopting a novel method of analyzing the production of pairs in annihilation, the center-of-mass energies are measured with a precision of 0.6 MeV. Integrated luminosities are measured with a precision of better than 1% by analyzing the events of large-angle Bhabha scattering. These measurements provide important inputs to analyses based on these data samples.
|
|
| 5. |
- Ablikim, M., et al.
(författare)
-
Measurement of singly Cabibbo-suppressed decays D -> ωππ
- 2020
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 1550-7998 .- 1550-2368. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2.93 fb(-1) of e(+) e(-) collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays D -> omega pi pi to be B(D-0 -> omega pi(+) pi(-)) = (1.33 +/- 0.16 +/- 0.12) x 10(-3) and B(D+ -> omega pi(+)pi(0)) = (3.87 +/- 0.83 +/- 0.25) x 10(-3), where the first uncertainties are statistical and the second ones systematic. The statistical significances are 12.9 sigma and 7.7 sigma, respectively. The precision of B(D-0 -> omega pi(+) pi(-)) is improved by a factor of 2.1 over prior measurements, and B(D+ -> omega pi(+) pi(0)) is measured for the first time. No significant signal for D-0 -> omega pi(0)pi(0) is observed, and the upper limit on the branching fraction is B(D-0 -> omega pi(0)pi(0)) < 1.10 x 10(-3) at the 90% confidence level. The branching fractions of D -> eta pi pi are also measured and consistent with existing results.
|
|
| 6. |
- Ablikim, M., et al.
(författare)
-
Measurement of the doubly Cabibbo-suppressed decay D+→K+π+π−π0 with semileptonic tags
- 2021
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:7
-
Tidskriftsartikel (refereegranskat)abstract
- We propose a new semileptonic tag method to study the doubly Cabibbo-suppressed D decay in psi(3770) -> D (D) over bar reaction. Utilizing the dataset corresponding to an integrated luminosity of 2.93 fb(-1) at a center-of-mass energy of 3.773 GeV collected by the BESIII detector, we determine the branching fraction for D+ -> K+pi(+)pi(-)pi(0) to be (1.03 +/- 0.12(stat) +/- 0.06(syst)) x 10(-3), in which the contributions from narrow intermediate resonances, D+ -> K+eta, D+ -> K+omega, and D+ -> K+phi have been excluded. Combining the world average of the branching fraction of D+ -> K+pi(+)pi(-)pi(0), we determine B(D+ -> K+pi(+)pi(-)pi(0))/B(D+ -> K+pi(+)pi(-)pi(0)) = (1.65 +/- 0.21)%, corresponding to (5.73 +/- 0.73) tan(4)theta(c), where theta(c) is the Cabibbo mixing angle. These results are consistent with our previous measurement with hadronic tags but are significantly larger than other doubly Cabibbo-suppressed decays in the charm sector.
|
|
| 7. |
- 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
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:1
-
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.
|
|
| 8. |
- Ablikim, M., et al.
(författare)
-
Measurement of the proton form factor by studying e(+)e(-) -> p(p)over-tilde
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e(+)e(-) -> p (p) over tilde at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (vertical bar G(E)vertical bar = vertical bar G(M)vertical bar). In addition, the ratio of electric to magnetic form factors, vertical bar G(E)/G(M)vertical bar, and vertical bar G(M)vertical bar are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at root s = 2232.4 and 2400.0 MeV and a combined sample at root s = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BABAR, improving the overall uncertainty by about 30%. The vertical bar G(E)/G(M)vertical bar ratios are close to unity and consistent with BABAR results in the same q(2) region, which indicates the data are consistent with the assumption that vertical bar G(E)vertical bar = vertical bar G(M)vertical bar within uncertainties.
|
|
| 9. |
- Ablikim, M., et al.
(författare)
-
Measurements of e(+)e(-)-> (KSK +/-)-K-0 pi(-/+)pi(0) and (KSK +/-)-K-0 pi(-/+)eta at center-of-mass energies from 3.90 to 4.60 GeV
- 2019
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 99:1
-
Tidskriftsartikel (refereegranskat)abstract
- Using 5.2 fb(-1) e(+)e(-) annihilation data samples collected with the BESIII detector, we measure the cross sections of e(+)e(-)->(KSK +/-)-K-0 pi(-/+)pi(0) and (KSK +/-)-K-0 pi(-/+)eta at center-of-mass energies from 3.90 to 4.60 GeV. In addition, we search for the charmoniumlike resonance Y(4260) decays into (KSK +/-)-K-0 pi(-/+)pi(0) and (KSK +/-)-K-0 pi(-/+)eta and Z(c)(0,+/-) (3900) decays into (KSK +/-)-K-0 pi(-/+)(,0) and (KSK +/-)-K-0 eta. Corresponding upper limits are provided since no clear signal is observed.
|
|
| 10. |
|
|
