Refine
Year of publication
Language
- English (581)
Has Fulltext
- yes (581)
Is part of the Bibliography
- no (581)
Keywords
- BESIII (20)
- e +-e − Experiments (19)
- Branching fraction (15)
- Particle and Resonance Production (8)
- Charm Physics (6)
- Quarkonium (6)
- Hadronic decays (5)
- QCD (5)
- Spectroscopy (5)
- Branching fractions (4)
- Charmonium (4)
- Exotics (4)
- Lepton colliders (4)
- Charmed mesons (3)
- Electroweak Interaction (3)
- Electroweak interaction (3)
- Initial state radiation (3)
- e+-e− Experiments (3)
- Absolute branching fraction (2)
- Bhabha (2)
- Charm physics (2)
- Cross section (2)
- Flavour Physics (2)
- Hadronic cross section (2)
- Leptonic, semileptonic & radiative decays (2)
- Muon anomaly (2)
- Particle decays (2)
- Pion form factor (2)
- Radiative decay (2)
- center-of-mass energy (2)
- decays (2)
- luminosity (2)
- Angular distribution (1)
- Annihilation (1)
- BESIII detector (1)
- BSM particle (1)
- Bhabha scattering (1)
- Born cross section (1)
- Born cross section measurement (1)
- Branching fraction measurement (1)
- CP violation (1)
- Charm vector (1)
- Charmed baryon (1)
- Charmonium (-like) (1)
- Covariance matrix (1)
- Cross section measurements (1)
- D meson (1)
- D0 and D+ mesons (1)
- Dalitz decay (1)
- Dark photon (1)
- Dark sector (1)
- D⁰ meson (1)
- Effective form factor (1)
- Electromagnetic amplitude (1)
- Electromagnetic form factor (1)
- Electromagnetic form factors (1)
- Experimental nuclear physics (1)
- Experimental particle physics (1)
- FCNC process (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Form factors (1)
- Hadrons (1)
- Helicity amplitude analysis (1)
- Hyperon decay (1)
- Hyperons (1)
- Inclusive branching fraction (1)
- Initial State Radiation (1)
- Invariant Mass (1)
- Invisible decays (1)
- K0S (1)
- Monte Carlo (1)
- Neutrinos (1)
- Particle and resonance production (1)
- Particle phenomena (1)
- Phase (1)
- Polarization (1)
- Proton (1)
- Quantum chromodynamics (1)
- R value (1)
- Rare decays (1)
- Semi-leptonic decays (1)
- Semileptonic Decay (1)
- Strong amplitude (1)
- Systematic Uncertainty (1)
- Techniques Electromagnetic calorimeters (1)
- Threshold effect (1)
- Triple quarkonia (1)
- W-exchange (1)
- Y (4260) (1)
- Y states (1)
- branching fractions (1)
- charmed baryon (1)
- charmonium-like states (1)
- decay (1)
- dimuon (1)
- diphoton (1)
- e+e − annihilation (1)
- e+e⁻ − Experiments (1)
- e+e− Experiments (1)
- e+e− annihilation (1)
- electron-positron collision (1)
- hadron spectroscopy (1)
- hadronic events (1)
- helicity amplitude analysis (1)
- inclusive J/ψ decays (1)
- number of J/ψ events (1)
- radiative dimuon events (1)
- tetraquark (1)
- trigger efficiency (1)
- Λ+c baryon (1)
- Λc⁺ (1)
- Σ hyperon (1)
- ψ(3686) (1)
Institute
- Physik (581) (remove)
Based on a data sample of (27.08±0.14)×108 ψ(3686) events collected with the BESIII detector at the BEPCII collider, the M1 transition ψ(3686)→γηc(2S) with ηc(2S)→KK¯π is studied, where KK¯π is K+K−π0 or K0SK±π∓. The mass and width of the ηc(2S) are measured to be (3637.8±0.8(stat)±0.2(syst)) MeV/c2 and (10.5±1.7(stat)±3.5(syst)) MeV, respectively. The product branching fraction B(ψ(3686)→γηc(2S))×B(ηc(2S)→KK¯π) is determined to be (0.97±0.06(stat)±0.09(syst))×10−5. Using BR(ηc(2S)→KK¯π)=(1.86+0.68−0.49)%, we obtain the branching fraction of the radiative transition to be BR(ψ(3686)→γηc(2S))=(5.2±0.3(stat)±0.5(syst)+1.9−1.4(extr))×10−4, where the third uncertainty is due to the quoted BR(ηc(2S)→KK¯π).
The J/ψ→Ξ0Ξ¯0 process and subsequent decays are investigated using (10087±44)×106 J/ψ events collected at the BESIII experiment. The decay parameters of Ξ0 and Ξ¯0 are measured with greatly improved precision over previous measurements to be αΞ=−0.3750±0.0034±0.0016, α¯Ξ=0.3790±0.0034±0.0021, ϕΞ=0.0051±0.0096±0.0018~rad, ϕ¯Ξ=−0.0053±0.0097±0.0019~rad, where the first and the second uncertainties are statistical and systematic, respectively. From these measurements, precise CP symmetry tests in Ξ0 decay are performed, and AΞCP=(−5.4±6.5±3.1)×10−3 and ΔϕΞCP=(−0.1±6.9±0.9)×10−3~rad are consistent with CP conservation. The sequential decay also enables a separation of weak and strong phase differences, which are found for the first time to be ξP−ξS=(0.0±1.7±0.2)×10−2~rad and δP−δS=(−1.3±1.7±0.4)×10−2~rad, respectively. In addition, we measure the Λ decay parameters and test CP symmetry in Λ decays.
Using initial-state radiation events from a total integrated luminosity of 11.957 fb−1 of 𝑒+𝑒− collision data collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at BEPCII, the cross section for the process 𝑒+𝑒−→Λ¯Λ is measured in 16 Λ¯Λ invariant mass intervals from the production threshold up to 3.00 GeV/𝑐2. The results are consistent with previous results from BABAR and BESIII, but with better precision and with narrower Λ¯Λ invariant mass intervals than BABAR.
The process e+e−→D∗+sD∗−s is studied with a semi-inclusive method using data samples at center-of-mass energies from threshold to 4.95 GeV collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections of the process are measured for the first time with high precision in this energy region. Two resonance structures are observed in the energy-dependent cross sections around 4.2 and 4.4 GeV. By fitting the cross sections with a coherent sum of three Breit-Wigner amplitudes and one phase-space amplitude, the two significant structures are assigned masses of (4186.5±9.0±30) MeV/c2 and (4414.5±3.2±6.0) MeV/c2, widths of (55±17±53) MeV and (122.6±7.0±8.2) MeV, where the first errors are statistical and the second ones are systematic. The inclusion of a third Breit-Wigner amplitude is necessary to describe a structure around 4.79 GeV.
The measurement of the Cabibbo-favored semileptonic decay Λ+c→Λμ+νμ is reported using 4.5 fb−1 of e+e− annihilation data collected at center-of-mass energies ranging from 4.600~GeV to 4.699~GeV. The branching fraction of the decay is measured to be B(Λ+c→Λμ+νμ)=(3.48±0.14stat.±0.10syst.)%, three times more precise than the prior world average result. Tests of lepton flavor universality using Λ+c→Λℓ+νℓ (ℓ=e,μ) decays are reported for the first time, based on measurements of the differential decay rates and the forward-backward asymmetries in separate four-momentum transfer regions. The results are compatible with Standard Model predictions. Furthermore, we improve the determination of the form-factor parameters in Λ+c→Λℓ+νℓ decays, which provide stringent tests and calibration for lattice quantum chromodynamics (LQCD) calculations.
We report the measurement of the inclusive cross sections for e+e−→nOCH (where nOCH denotes non-open charm hadrons) with improved precision at center-of-mass (c.m.) energies from 3.645 to 3.871 GeV. We observe three resonances: R(3760), R(3780), and R(3810) with significances of 8.1σ, 13.7σ, and 8.8σ, respectively. The R(3810) state is observed for the first time, while the R(3760) and R(3780) states are observed for the first time in the nOCH cross sections. Two sets of resonance parameters describe the energy-dependent line shape of the cross sections well. In set I [set II], the R(3810) state has mass (3805.7±1.1±2.7) [(3805.7±1.1±2.7)] MeV/c2, total width (11.6±2.9±1.9) [(11.5±2.8±1.9)] MeV, and an electronic width multiplied by the nOCH decay branching fraction of (10.9±3.8±2.5) [(11.0±3.4±2.5)] eV. In addition, we measure the branching fractions B[R(3760)→nOCH]=(25.2±16.1±30.4)%[(6.4±4.8±7.7)%] and B[R(3780)→nOCH]=(12.3±6.6±8.3)%[(10.4±4.8±7.0)%] for the first time. The R(3760) state can be interpreted as an open-charm (OC) molecular state, but containing a simple four-quark state component. The R(3810) state can be interpreted as a hadrocharmonium state.
Using 7.33 fb−1 of e+e− collision data taken with the BESIII detector at the BEPCII collider, we report the first experimental study of the purely leptonic decay D∗+s→e+νe. A signal for the decay D∗+s→e+νe is observed with a statistical significance of 2.9σ. The branching fraction of D∗+s→e+νe is measured to be (2.1+1.2−0.9stat.±0.2syst.)×10−5, corresponding to an upper limit of 4.0×10−5 at the 90\% confidence level. Taking the total width of the D∗+s~((0.070±0.028) keV) predicted by lattice quantum chromodynamics as input, the decay constant of the D∗+s is determined to be fD∗+s=(213.6+61.0−45.8stat.±43.9syst.) MeV, corresponding to an upper limit of 353.8 MeV at the 90\% confidence level.
Using a sample of about 10 billion J/ψ events with the BESIII detector, we search for the weak decays of J/ψ→D¯0π0+c.c., J/ψ→D¯0η+c.c., J/ψ→D¯0ρ0+c.c., J/ψ→D−π++c.c., and J/ψ→D−ρ++c.c.. Since no significant signal is observed, we set the upper limits of the branching fractions of these decays to be B(J/ψ→D¯0π0+c.c.)<4.7×10−7, B(J/ψ→D¯0η+c.c.)<6.8×10−7, B(J/ψ→D¯0ρ0+c.c.)<5.2×10−7, B(J/ψ→D−π++c.c.)<7.0×10−8, and B(J/ψ→D−ρ++c.c.)<6.0×10−7 at the 90\% confidence level.
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure \textit{W}-boson-exchange decay Λ+c→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat.)±0.03(syst.). This result reflects the non-interference effect between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes has two solutions, which are δp−δs=−1.55±0.25(stat.)±0.05(syst.) rad or 1.59±0.25(stat.)±0.05(syst.) rad.
Based on data samples collected with the BESIII detector at the BEPCII collider, the process e+e−→Σ+Σ¯− is studied at center-of-mass energies s√ = 2.3960, 2.6454, and 2.9000 GeV. Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the Σ+ electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sinΔΦ = -0.67~±~0.29~(stat)~±~0.18~(syst) at s√ = 2.3960 GeV, ΔΦ = 55∘~±~19∘~(stat) ±~14∘~(syst) at s√ = 2.6454 GeV, and 78∘~±~22∘~(stat) ±~9∘~(syst) at s√ = 2.9000 GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four-momentum transfer. The evolution of the phase along with four-momentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure \textit{W}-boson-exchange decay Λ+c→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat.)±0.03(syst.). This result reflects the non-interference effect between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes has two solutions, which are δp−δs=−1.55±0.25(stat.)±0.05(syst.) rad or 1.59±0.25(stat.)±0.05(syst.) rad.
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-exchange decay Λ+c→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat.)±0.03(syst.). This result reflects the interference between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes is δp−δs=−1.55±0.25(stat.)±0.05(syst.) rad.
The singly Cabibbo-suppressed decay Λ+𝑐→Σ−𝐾+𝜋+ is observed for the first time with a statistical significance of 5.4𝜎 by using 4.5 fb−1 of 𝑒+𝑒− collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. The absolute branching fraction of Λ+𝑐→Σ−𝐾+𝜋+ is measured to be (3.8±1.2stat±0.2syst)×10−4 in a model-independent approach. This is the first observation of a Cabibbo-suppressed Λ+𝑐 decay involving Σ− in the final state. The ratio of branching fractions between Λ+𝑐→Σ−𝐾+𝜋+ and the Cabibbo-favored decay Λ+𝑐→Σ−𝜋+𝜋+ is observed to be (0.4±0.1)𝑠2𝑐, where 𝑠𝑐≡sin𝜃𝑐=0.2248 with 𝜃𝑐 the Cabibbo mixing angle.
Using a data sample of (10087±44)×106 J/ψ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process J/ψ→e+e−η(1405) is observed via the decay η(1405)→π0f0(980), f0(980)→π+π−, with a significance of about 9.6σ. The branching fraction of this decay is measured to be B(J/ψ→e+e−π0η(1405)→e+e−π0f0(980)→e+e−π0π+π−)=(2.02±0.24(stat.)±0.09(syst.))×10−7. The branching-fraction ratio B(J/ψ→e+e−η(1405))/B(J/ψ→γη(1405)) is determined to be (1.35±0.19(stat.)±0.06(syst.))×10−2. Furthermore, an e+e− invariant-mass dependent transition form factor of J/ψ→e+e−η(1405) is presented for the first time. The obtained result provides input for different theoretical models, and is valuable for the improved understanding the intrinsic structure of the η(1405) meson.
Using 7.33 fb−1 of e+e− collision data taken with the BESIII detector at the BEPCII collider, we report the first experimental study of the purely leptonic decay D∗+s→e+νe. A signal for the decay D∗+s→e+νe is observed with a statistical significance of 2.9σ. The branching fraction of D∗+s→e+νe is measured to be (2.1+1.2−0.9stat.±0.2syst.)×10−5, corresponding to an upper limit of 4.0×10−5 at the 90\% confidence level. Taking the total width of the D∗+s~((0.070±0.028) keV) predicted by lattice quantum chromodynamics as input, the decay constant of the D∗+s is determined to be fD∗+s=(213.6+61.0−45.8stat.±43.9syst.) MeV, corresponding to an upper limit of 353.8 MeV at the 90\% confidence level.
The cross sections of the e+e−→ϕη′ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb−1 data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn, and decrease as the center-of-mass energy increases as s−n/2 with n=4.35±0.14. This result is in agreement with the Nambu-Jona-Lasinio model prediction of n=3.5±0.9. In addition, the charmless decay ψ(3770)→ϕη′ is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of B(ψ(3770)→ϕη′) at the 90\% confidence level is determined to be 2.3×10−5.
The cross sections of the e+e−→ϕη′ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb−1 data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn, and decrease as the center-of-mass energy increases as s−n/2 with n=4.35±0.14. This result is in agreement with the Nambu-Jona-Lasinio model prediction of n=3.5±0.9. In addition, the charmless decay ψ(3770)→ϕη′ is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of B(ψ(3770)→ϕη′) at the 90\% confidence level is determined to be 2.3×10−5.
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-exchange decay Λ+c→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat.)±0.03(syst.). This result reflects the interference between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes is δp−δs=−1.55±0.25(stat.)±0.05(syst.) rad.
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-exchange decay Λ+c→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat.)±0.03(syst.). This result reflects the interference between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes is δp−δs=−1.55±0.25(stat.)±0.05(syst.) rad.
We present cross sections for the reaction e+e−→K0SK0L at center-of-mass energies ranging from 3.51 GeV to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb−1. The ratio of neutral-to-charged kaon form factors at large momentum transfers (12 GeV2<Q2<25 GeV2) is determined to be 0.21±0.01, which indicates a small but significant effect of flavor-SU(3) breaking in the kaon wave function, and consequently excludes the possibility that flavor-SU(3) breaking is the primary reason for the strong experimental violation of the pQCD prediction |F(π±)|/|F(K±)|=f2π/f2K, where F(π±) and F(K±) are the form factors, and fπ and fK are the decay constants of charged pions and kaons, respectively. We also observe a significant signal for the charmless decay ψ(3770)→K0SK0L for the first time. Within a 1σ contour of the likelihood value, the the branching fraction for ψ(3770)→K0SK0L is determined to be B=(2.63+1.40−1.59)×10−5, and the relative phase between the continuum and ψ(3770) amplitudes is ϕ=(−0.39+0.05−0.10)π. The branching fraction is in good agreement with the S- and D-wave charmonia mixing scheme proposed in the interpretation of the "ρπ puzzle" between J/ψ and ψ(3686) decays.