Refine
Year of publication
Language
- English (486)
Has Fulltext
- yes (486)
Is part of the Bibliography
- no (486)
Keywords
- e +-e − Experiments (20)
- Branching fraction (14)
- Particle and Resonance Production (9)
- BESIII (8)
- Charm Physics (6)
- Quarkonium (6)
- Spectroscopy (6)
- QCD (5)
- Exotics (4)
- Charmed mesons (3)
- Electroweak Interaction (3)
- Electroweak interaction (3)
- Lepton colliders (3)
- e+-e− Experiments (3)
- Charm physics (2)
- Charmonium (2)
- Flavour Physics (2)
- Hadronic decays (2)
- Leptonic, semileptonic & radiative decays (2)
- Particle decays (2)
- Radiative decay (2)
- B-slope (1)
- BESIII detector (1)
- BSM particle (1)
- Born cross section (1)
- Born cross section measurement (1)
- Branching fraction measurement (1)
- Branching fractions (1)
- CP violation (1)
- Charm vector (1)
- Charmonium (-like) (1)
- Coalescence (1)
- Collectivity (1)
- Correlation (1)
- Critical point (1)
- Dark photon (1)
- Dark sector (1)
- Deuteron production (1)
- Diffraction (1)
- Effective form factor (1)
- Elastic scattering (1)
- Electromagnetic form factors (1)
- FCNC process (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Heavy-ion collisions (1)
- Helicity amplitude analysis (1)
- Higher moments (1)
- Hyperon decay (1)
- Initial state radiation (1)
- Invisible decays (1)
- Neutrinos (1)
- Particle and resonance production (1)
- Particle phenomena (1)
- Polarization (1)
- Proton (1)
- Proton–proton collisions (1)
- Rare decays (1)
- Semi-leptonic decays (1)
- Shear viscosity (1)
- Thermal model (1)
- Threshold effect (1)
- Y states (1)
- center-of-mass energy (1)
- charmonium-like states (1)
- e+e − annihilation (1)
- e+e⁻ − Experiments (1)
- e+e− Experiments (1)
- electron-positron collision (1)
- hadron spectroscopy (1)
- helicity amplitude analysis (1)
- inclusive J/ψ decays (1)
- number of J/ψ events (1)
- tetraquark (1)
- Λ+c baryon (1)
Institute
- Physik (474)
- Frankfurt Institute for Advanced Studies (FIAS) (8)
- Medizin (1)
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.
Measurements of the electric and magnetic form factors of the neutron for timelike momentum transfer
(2023)
We present the first measurements of the electric and magnetic form factors of the neutron in the time-like (positive q2) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e+e−→n¯n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb−1 in total at twelve center-of-mass energies between s√=2.0−2.95 GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at s√=2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable space-like (negative q2) region of four-momentum transfer. The electromagnetic form factor ratio Rem≡|GE|/|GM| is within the uncertainties close to unity. We compare our result on |GE| and |GM| to recent model predictions, and the measurements in the space-like region to test the analyticity of electromagnetic form factors.
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 \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.
Using e+e− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching fractions of the inclusive decays D0→π+π+π−X and D+→π+π+π−X, where pions from K0S decays have been excluded from the π+π+π− system and X denotes any possible particle combination. The branching fractions of D0(D+)→π+π+π−X are determined to be B(D0→π+π+π−X)=(17.60±0.11±0.22)% and B(D+→π+π+π−X)=(15.25±0.09±0.18)%, where the first uncertainties are statistical and the second systematic.
Using a data sample of e+e− collision data corresponding to an integrated luminosity of 19 fb−1 collected with the BESIII detector at the BEPCII collider, we search for the production of deuterons and antideuterons via e+e−→ppπ−d¯+c.c. for the first time at center-of-mass energies between 4.13 and 4.70 GeV. No significant signal is observed and the upper limit of the e+e−→ppπ−d¯+c.c. cross section is determined to be from 9.0 to 145 fb depending on the center-of-mass energy at the 90% confidence level.
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.