Refine
Year of publication
Document Type
- Article (145) (remove)
Has Fulltext
- yes (145)
Is part of the Bibliography
- no (145)
Keywords
- BESIII (14)
- e +-e β Experiments (11)
- Branching fraction (7)
- Particle and Resonance Production (7)
- Spectroscopy (5)
- Branching fractions (4)
- Charm Physics (4)
- Hadronic decays (4)
- Exotics (3)
- LHC (3)
Institute
- Physik (137)
- Frankfurt Institute for Advanced Studies (FIAS) (5)
- Informatik (5)
- Medizin (3)
By analyzing π+β’πβ annihilation data with an integrated luminosity of 2.93ββfbβ1 collected at the center-of-mass energy βπ =3.773βGeV with the BESIII detector, we present the first absolute measurements of the branching fractions of twenty Cabibbo-suppressed hadronic π·0β’(+) decays involving multiple pions. The highest four branching fractions obtained are β¬β‘(π·0βπ+β’πββ’π0) = (1.343Β±0.01β’3statΒ±0.01β’6syst)%, β¬β‘(π·0βπ+β’πββ’2β’π0) = (1.002Β±0.01β’9statΒ±0.02β’4syst)%, β¬β‘(π·+β2β’π+β’πββ’π0) = (1.165Β±0.02β’1statΒ±0.02β’1syst)%, and β¬β‘(π·+β2β’π+β’πββ’2β’π0) = (1.074Β±0.04β’0statΒ±0.03β’0syst)%. The πΆβ’π asymmetries for the six decays with highest signal yields are also determined and found to be compatible with zero.
The hadronic decay ππβ‘(2β’π)β3β’(π+β’πβ) is observed with a statistical significance of 9.3 standard deviations using (448.1Β±2.9)Γ106ββπβ‘(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ππβ‘(2β’π) are (3643.4Β±2.3β(stat)Β±4.4β(syst))ββMeV/π2 and (19.8Β±3.9β(stat)Β±3.1β(syst))ββMeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]Γβ¬β‘[ππβ‘(2β’π)β3β’(π+β’πβ)] is measured to be (9.2Β±1.0β(stat)Β±1.2β(syst))Γ10β6. Using β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]=(7.β’0+3.4β2.5)Γ10β4, we obtain β¬β‘[ππβ‘(2β’π)β3β’(π+β’πβ)]=(1.31Β±0.15β(stat)Β±0.17β(syst) (+0.64β0.47)β(extr))Γ10β2, where the third uncertainty is from β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]. We also measure the ππβ’π½β3β’(π+β’πβ) (π½=0, 1, 2) decays via πβ²βπΎβ’ππβ’π½ transitions. The branching fractions are β¬β‘[ππβ’0β3β’(π+β’πβ)]=(2.080Β±0.006β(stat)Β±0.068β(syst))Γ10β2, β¬β‘[ππβ’1β3β’(π+β’πβ)]=(1.092Β±0.004β(stat)Β±0.035β(syst))Γ10β2, and β¬β‘[ππβ’2β3β’(π+β’πβ)]=(1.565Β±0.005β(stat)Β±0.048β(syst))Γ10β2.
By analyzing an electron-positron collision data sample corresponding to an integrated luminosity of 2.93ββfbβ1 taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, we obtain for the first time the absolute branching fractions for seven π·0 and π·+ hadronic decay modes and search for the hadronic decay π·0βπΎ0πβ’πΎ0πβ’π0 with much improved sensitivity. The results are β¬β‘(π·0βπΎ0πβ’π0β’π0β’π0)=(7.64Β±0.30Β±0.29)Γ10β3, β‘(π·0βπΎββ’π+β’π0β’π0β’π0)=9.54Β±0.30Β±0.31)Γ10β3, β¬β‘(π·0βπΎ0πβ’π+β’πββ’π0β’π0)=(12.66Β±0.45Β±0.43)Γ10β3, β¬β‘(π·+βπΎ0πβ’π+β’π0β’π0)=(29.04Β±0.62Β±0.87)Γ10β3, β¬β‘(π·+βπΎ0πβ’π+β’π+β’πββ’π0)=(15.28Β±0.57Β±0.60)Γ10β3, β¬β‘(π·+βπΎ0πβ’π+β’π0β’π0β’π0)=(5.54Β±0.44Β±0.32)Γ10β3, β¬β‘(π·+βπΎββ’π+β’π+β’π0β’π0)=(4.95Β±0.26Β±0.19)Γ10β3, and β¬β‘(π·0βπΎ0πβ’πΎ0πβ’π0)<1.45Γ10β4 at the 90% confidence level. Here, the first uncertainties are statistical, and the second ones are systematic. The newly studied decays greatly enrich the knowledge of the π·βΒ―πΎβ’πβ’πβ’π and π·βΒ―πΎβ’πβ’πβ’πβ’π hadronic decays and open a bridge to access more two-body hadronic π· decays containing scalar, vector, axial, and tensor mesons in the charm sector.
We search for the semi-leptonic decays Ξ + c β ΞΟ+Οβe+Ξ½e and Ξ + c β pK0 SΟβe+Ξ½e in a sample of 4.5 fbβ1 of e+eβ annihilation data collected in the center-of-mass energy region between 4.600 GeV and 4.699 GeV by the BESIII detector at the BEPCII. No significant signals are observed, and the upper limits on the decay branching fractions are set to be B(Ξ+c β ΞΟ+Οβe+Ξ½e ) < 3.9 Γ 10β4 and B(Ξ + c β pK0SΟβe+Ξ½e ) < 3.3 Γ 10β4 at the 90% confidence level, respectively.
Measurement of branching fractions of _Ξ__(c)βΊ decays to Ξ£+K+Kβ, Ξ£+Ο and Ξ£+K+Οβ(Ο0)
(2023)
Based on 4.5 fbβ1 data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of Ξ + c β Ξ£ + + hadrons relative to Ξ + c β Ξ£ +Ο +Ο β. Combining with the world average branching fraction of Ξ + c β Ξ£ +Ο +Ο β, their branching fractions are measured to be (0.377 Β± 0.042 Β± 0.020 Β± 0.021)% for Ξ + c β Ξ£ +K+Kβ, (0.200 Β± 0.023 Β± 0.011 Β± 0.011)% for Ξ + c β Ξ£+K+Οβ, (0.414 Β± 0.080 Β± 0.030 Β± 0.023)% for Ξ + c β Ξ£ +Ο and (0.197 Β± 0.036 Β± 0.009 Β± 0.011)% for Ξ + c β Ξ£ +K+Kβ(non-Ο). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of Ξ + c β Ξ£ +Ο +Ο β. Since no signal for Ξ + c β Ξ£ +K+ΟβΟ 0 is observed, the upper limit of its branching fraction is determined to be 0.13% at the 90% confidence level.
With data samples collected with the BESIII detector at seven energy points at βs = 3.68 β 3.71 GeV, corresponding to an integrated luminosity of 333 pbβ1, we present a study of the Ξ transverse polarization in the e+eβ β ΞΞΒ― reaction. The signifcance of polarization by combining the seven energy points is found to be 2.6Ο including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the ΞΞΒ― helicity states. The modulus ratio and the relative phase of EM-psionic form factors combined with all energy points are measured to be RΞ¨ = 0.71+0.10β0.10 Β± 0.03 and βΦΨ = 23+8.8β8.0 Β± 1.6β¦, where the frst uncertainties are statistical and the second systematic.
A search for a massless dark photon πΎβ² is conducted using 4.5ββfbβ1 of π+β’πβ collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. No significant signal is observed, and the upper limit on the branching fraction β¬β‘(Ξ+πβπβ’πΎβ²) is determined to be 8.0Γ10β5 at 90% confidence level.
Using (1310.6Β±7.0)Γ106 π½/π events acquired with the BESIII detector at the BEPCII storage rings, the decay πβ²βπ+β’πββ’π+β’πβ is observed for the first time with a significance of 8β’π via the process π½/πβπΎβ’πβ². We measure the branching fraction of πβ²βπ+β’πββ’π+β’πβ to be β¬β‘(πβ²βπ+β’πββ’π+β’πβ)=(1.97Β±0.33β’(stat)Β±0.19β’(syst))Γ10β5, where the first and second uncertainties are statistical and systematic, respectively
The cross sections of e+eββK+KβJ/Ο at center-of-mass energies from 4.127 to 4.600~GeV are measured based on 15.6 fbβ1 data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in the line shape of the cross sections. The mass and width of the first structure are measured to be (4225.3Β±2.3Β±21.5) MeV and (72.9Β±6.1Β±30.8)~MeV, respectively. They are consistent with those of the established Y(4230). The second structure is observed for the first time with a statistical significance greater than 8Ο, denoted as Y(4500). Its mass and width are determined to be (4484.7Β±13.3Β±24.1) MeV and (111.1Β±30.1Β±15.2) MeV, respectively. The first presented uncertainties are statistical and the second ones are systematic. The product of the electronic partial width with the decay branching fraction Ξ(Y(4230)βe+eβ)B(Y(4230)βK+KβJ/Ο) is reported.
We report new measurements of the branching fraction β¬β‘(π·+π ββ+β’π), where β+ is either π+ or π+β‘(βπ+β’Β―ππ), based on 6.32ββfbβ1 of electron-positron annihilation data collected by the BESIII experiment at six center-of-mass energy points between 4.178 and 4.226 GeV. Simultaneously floating the π·+π βπ+β’ππ and π·+π βπ+β’ππ components yields β¬β‘(π·+π βπ+β’ππ)=(5.21Β±0.25Β±0.17)Γ10β2, β¬β‘(π·+π βπ+β’ππ)=(5.35Β±0.13Β±0.16)Γ10β3, and the ratio of decay widths π
=Ξβ‘(π·+π βπ+β’ππ)Ξβ‘(π·+π βπ+β’ππ)=9.7β’3+0.61β0.58Β±0.36, where the first uncertainties are statistical and the second systematic. No evidence of πΆβ’π asymmetry is observed in the decay rates π·Β±π βπΒ±β’ππ and π·Β±π βπΒ±β’ππ: π΄πΆβ’πβ‘(πΒ±β’π)=(β1.2Β±2.5Β±1.0)% and π΄πΆβ’πβ‘(πΒ±β’π)=(+2.9Β±4.8Β±1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (π
=9.75), we find the more precise results β¬β‘(π·+π βπ+β’ππ)=(5.22Β±0.10Β±0.14)Γ10β2 and π΄πΆβ’πβ‘(πΒ±β’ππ)=(β0.1Β±1.9Β±1.0)%. Combining our results with inputs external to our analysis, we determine the πβΒ―π quark mixing matrix element, π·+π decay constant, and ratio of the decay constants to be |ππβ’π |=0.973Β±0.009Β±0.014, ππ·+π =249.9Β±2.4Β±3.5ββMeV, and ππ·+π /ππ·+=1.232Β±0.035, respectively.