Refine
Year of publication
Document Type
- Article (244)
- Preprint (122)
- Working Paper (1)
Language
- English (367)
Has Fulltext
- yes (367)
Is part of the Bibliography
- no (367)
Keywords
- BESIII (14)
- Branching fraction (9)
- e +-e β Experiments (9)
- Particle and Resonance Production (6)
- Hadronic decays (5)
- Quarkonium (5)
- Branching fractions (4)
- Lepton colliders (4)
- Charm Physics (3)
- Charmed mesons (3)
Institute
By using 6.32 fbβ1 of data collected with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we perform an amplitude analysis of the decay D+s ! K0S +β0 and determine the relative fractions and phase differences of different intermediate processes, which include K0S (770)+, K0S (1450)+, Kβ(892)0β+, Kβ(892)+β0, and Kβ(1410)0β+. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D+s ! K0S +β0) = (5.43 Β± 0.30stat Β± 0.15syst) Γ 10β3.
We measure the inclusive semielectronic decay branching fraction of the D+s meson. A double-tag technique is applied to e+eβ annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range 4.178β4.230 GeV. We select positrons fromD+sβXe+Ξ½e with momenta greater than 200 MeV/c and determine the laboratory momentum spectrum, accounting for the effects of detector efficiency and resolution. The total positron yield and semielectronic branching fraction are determined by extrapolating this spectrum below the momentum cutoff. We measure the D+s semielectronic branching fraction to be(6.30Β±0.13(stat.)Β±0.09(syst.)Β±0.04(ext.))%, showing no evidence for unobserved exclusive semielectronic modes. We combine this result with external data taken from literature to determine the ratio of the D+s and D0 semielectronic widths, Ξ(D+sβXe+Ξ½e)Ξ(D0βXe+Ξ½e)=0.790Β±0.016(stat.)Β±0.011(syst.)Β±0.016(ext.). Our results are consistent with and more precise than previous measurements.
Using 10.1 Γ 109 J/Ο events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy βs = 3.097 GeV and collected with the BESIII detector, we present a search for the rare semi-leptonic decay J/Ο β Dβe+Ξ½e + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction B(J/Ο β Dβe +Ξ½e + c.c.) < 7.1 Γ 10β8 is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.
The integrated luminosities of data samples collected in the BESIII experiment in 2016β2017 at center-of-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events. The integrated luminosities of old datasets collected in 2010β2014 are updated by considering corrections related to detector performance, offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter, which can haphazardly occur.
Though immensely successful, the standard model of particle physics does not offer any explanation as to why our Universe contains so much more matter than antimatter. A key to a dynamically generated matterβantimatter asymmetry is the existence of processes that violate the combined charge conjugation and parity (CP) symmetry1. As such, precision tests of CP symmetry may be used to search for physics beyond the standard model. However, hadrons decay through an interplay of strong and weak processes, quantified in terms of relative phases between the amplitudes. Although previous experiments constructed CP observables that depend on both strong and weak phases, we present an approach where sequential two-body decays of entangled multi-strange baryonβantibaryon pairs provide a separation between these phases. Our method, exploiting spin entanglement between the double-strange Ξβ baryon and its antiparticle2 ΞΒ―+
, has enabled a direct determination of the weak-phase difference, (ΞΎPβββΞΎS)β= (1.2βΒ±β3.4βΒ±β0.8)βΓβ10β2βrad. Furthermore, three independent CP observables can be constructed from our measured parameters. The precision in the estimated parameters for a given data sample size is several orders of magnitude greater than achieved with previous methods3. Finally, we provide an independent measurement of the recently debated Ξ decay parameter Ξ±Ξ (refs.β4,5). The ΞΞΒ―
asymmetry is in agreement with and compatible in precision to the most precise previous measurement.
Based on an e+eβ collision data sample corresponding to an integrated luminosity of 2.93 fbβ1 collected with the BESIII detector at βs=3.773 GeV, the first amplitude analysis of the singly Cabibbo-suppressed decay D+βK+K0SΟ0 is performed. From the amplitude analysis, the Kβ(892)+K0S component is found to be dominant with a fraction of (57.1Β±2.6Β±4.2)%, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction B(D+βK+K0SΟ0) measured by BESIII, we obtain B(D+βKβ(892)+K0S)=(8.69Β±0.40Β±0.64Β±0.51)Γ10β3, where the third uncertainty is due to the branching fraction B(D+βK+K0SΟ0). The precision of this result is significantly improved compared to the previous measurement. This result also differs from most of theoretical predictions by about 4Ο, which may help to improve the understanding of the dynamics behind.
Using 2.93 fbβ1 of e+eβ collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D0βK1(1270)βe+Ξ½e semileptonic decay is presented. The statistical significance of the decay D0βK1(1270)βe+Ξ½e is greater than 10Ο. The branching fraction of D0βK1(1270)βe+Ξ½e is measured to be (1.09Β±0.13+0.09β0.16Β±0.12)Γ10β3. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K1(1270)ββKβΟ+Οβ. The fraction of longitudinal polarization in D0βK1(1270)βe+Ξ½e is determined for the first time to be 0.50Β±0.19statΒ±0.08syst.
Using 2.93 fbβ1 of e+eβ collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D0βK1(1270)βe+Ξ½e semileptonic decay is presented. The statistical significance of the decay D0βK1(1270)βe+Ξ½e is greater than 10Ο. The branching fraction of D0βK1(1270)βe+Ξ½e is measured to be (1.09Β±0.13+0.09β0.13Β±0.12)Γ10β3. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K1(1270)ββKβΟ+Οβ.
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.