Refine
Year of publication
Document Type
- Article (402)
- Preprint (314)
- Working Paper (1)
Language
- English (717)
Has Fulltext
- yes (717)
Is part of the Bibliography
- no (717)
Keywords
- BESIII (20)
- e +-e − Experiments (20)
- Branching fraction (15)
- Particle and Resonance Production (9)
- Charm Physics (6)
- Quarkonium (6)
- Spectroscopy (6)
- Hadronic decays (5)
- QCD (5)
- Branching fractions (4)
- Charmonium (4)
- Exotics (4)
- Heavy-ion collisions (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)
- Beam Energy Scan (2)
- Bhabha (2)
- Charm physics (2)
- Chiral Magnetic Effect (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)
- B-slope (1)
- BESIII detector (1)
- BSM particle (1)
- Beam energy scan (1)
- Bhabha scattering (1)
- Biological (1)
- Born cross section (1)
- Born cross section measurement (1)
- Branching fraction measurement (1)
- CP violation (1)
- Charm quark spatial diffusion coefficient (1)
- Charm vector (1)
- Charmed baryon (1)
- Charmonium (-like) (1)
- Chiral magnetic effect (1)
- Closure (1)
- Coalescence (1)
- Cold nuclear matter effects (1)
- Collectivity (1)
- Correlation (1)
- Covariance matrix (1)
- Critical point (1)
- Cross section measurements (1)
- D meson (1)
- D0 and D+ mesons (1)
- Dalitz decay (1)
- Dark photon (1)
- Dark sector (1)
- Deuteron production (1)
- Diffraction (1)
- D⁰ meson (1)
- Effective form factor (1)
- Elastic scattering (1)
- Electromagnetic amplitude (1)
- Electromagnetic form factor (1)
- Electromagnetic form factors (1)
- Elliptic flow (1)
- Experimental nuclear physics (1)
- Experimental particle physics (1)
- FCNC process (1)
- Fistula (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Form factors (1)
- Guidelines (1)
- Hadronization (1)
- Hadrons (1)
- Heavy Ion Experiments (1)
- Heavy Quark Production (1)
- Heavy ion collisions (1)
- Heavy-Ion Collision (1)
- Heavy-flavor decay electron (1)
- Helicity amplitude analysis (1)
- Higher moments (1)
- Hyperon decay (1)
- Hyperons (1)
- Inclusive branching fraction (1)
- Initial State Radiation (1)
- Intra-abdominal infection (1)
- Invariant Mass (1)
- Invisible decays (1)
- J/ψ suppression (1)
- K0S (1)
- Laparostomy (1)
- Mesh (1)
- Monte Carlo (1)
- Net-charge correlations (1)
- Net-charge fluctuations (1)
- Neutrinos (1)
- Non-trauma (1)
- Nutrition (1)
- Open abdomen (1)
- Pancreatitis (1)
- Particle and resonance production (1)
- Particle phenomena (1)
- Peritonitis (1)
- Phase (1)
- Polarization (1)
- Proton (1)
- Proton–proton collisions (1)
- Quantum chromodynamics (1)
- R value (1)
- RHIC (1)
- Rare decays (1)
- Re-exploration (1)
- Reintervention (1)
- STAR (1)
- Semi-leptonic decays (1)
- Semileptonic Decay (1)
- Shear viscosity (1)
- Strong amplitude (1)
- Synthetic (1)
- Systematic Uncertainty (1)
- Technique (1)
- Techniques Electromagnetic calorimeters (1)
- Thermal model (1)
- Threshold effect (1)
- Timing (1)
- Trauma (1)
- Triple quarkonia (1)
- Vascular emergencies (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)
- heavy-ion collisions (1)
- helicity amplitude analysis (1)
- inclusive J/ψ decays (1)
- newly diagnosed glioblastoma (1)
- nivolumab (1)
- number of J/ψ events (1)
- radiative dimuon events (1)
- radiotherapy (1)
- temozolomide (1)
- tetraquark (1)
- trigger efficiency (1)
- unmethylated MGMT (1)
- Λ+c baryon (1)
- Λc⁺ (1)
- Σ hyperon (1)
- Υ suppression (1)
- ψ(3686) (1)
The Born cross section of the process e+e−→ΛΛ¯ is measured at 33 center-of-mass energies between 3.51 and 4.60 GeV using data corresponding to the total integrated luminosity of 20.0 fb−1 collected with the BESIII detector at the BEPCII collider. Describing the energy dependence of the cross section requires a justification from the ψ(3770)→ΛΛ¯ decay, which is fitted with a significance of 4.9σ with the systematic uncertainty included. The lower bound on its branching fraction is 2.4×10−6 at the 90\% confidence level (C.L.), at least five times larger than expected from predictions using a simple scaling approach. This result indicates the importance of effects from vector charmonium(-like) when interpreting data in terms of {\it e.g.}, electromagnetic structure observables. There are no definite conclusions about the interplay with other vector charmonium(-like), and we set 90\% C.L.upper limits for the products of the electronic widths and the branching fractions.
Using a data set corresponding to an integrated luminosity of 6.32 fb−1 recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the decay D+s → π+π0π0 is performed, and the relative fractions and phases of different intermediate processes are determined. The absolute branching fraction of the decay D+s → π+π0π0 is measured to be (0.50 ± 0.04stat ± 0.02syst)%. Theabsolute branching fraction of the intermediate process D+s → f0(980)π+, f0(980) → π0π0 is determined to be (0.28 ± 0.04stat ± 0.04syst)%.
Using a data sample corresponding to an integrated luminosity of 2.93 fb−1 collected at a center-of-mass energy s√=3.773 GeV by the BESIII detector, the decay D0→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.38)×10−4 with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D0→ωϕ decay are transversely polarized, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.
Using a data sample corresponding to an integrated luminosity of 2.93 fb−1 collected at a center-of-mass energy s√=3.773 GeV by the BESIII detector, the decay D0→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10−4 with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D0→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.
Using a data sample corresponding to an integrated luminosity of 2.93 fb−1 collected at a center-of-mass energy s√=3.773 GeV by the BESIII detector, the decay D0→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.38)×10−4 with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D0→ωϕ decay are transversely polarized.
Based on a sample of 448.1×106 ψ(3686) events collected with the BESIII detector, a study of ψ(3686)→ΛΛ¯π0 and ψ(3686)→ΛΛ¯η is performed. Evidence of the isospin-violating decay ψ(3686)→ΛΛ¯π0 is found for the first time with a statistical significance of 3.7σ, the branching fraction B(ψ(3686)→ΛΛ¯π0) is measured to be (1.42±0.39±0.59)×10−6, and its corresponding upper limit is determined to be 2.47×10−6 at 90\% confidence level. A partial wave analysis of ψ(3686)→ΛΛ¯η shows that the peak around Λη invariant mass threshold favors a Λ∗ resonance with mass and width in agreement with the Λ(1670). The branching fraction of the ψ(3686)→ΛΛ¯η is measured to be (2.34±0.18±0.52)×10−5. The first uncertainties are statistical and the second are systematic.
We present the first search for the semileptonic decay D+s→π0e+νe using a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, corresponding to an integrated luminosity of 6.32~fb−1. This decay is expected to be sensitive to π0--η mixing. No significant signal is observed. We set an upper limit of 6.4×10−5 on the branching fraction at the 90% confidence level.
Measurement of the e⁺e⁻ → ωπ⁰π⁰ cross section at center-of-mass energies from 2.0 to 3.08 GeV
(2022)
The cross section of the process e+e−→ωπ0π0 is measured at nineteen center-of-mass energies from 2.0 to 3.08 GeV using data collected with the BESIII detector at the BEPCII storage ring. A resonant structure around 2.20 GeV is observed with statistical significance larger than 5σ. Using a coherent fit to the cross section line shape, the mass and width are determined to be M=2222±7±2 MeV/c2 and Γ=59±30±6 MeV, respectively, where the first uncertainties are statistical and the second ones are systematic.
Ten hadronic final states of the ℎ𝑐 decays are investigated via the process 𝜓(3686)→𝜋0ℎ𝑐, using a data sample of (448.1±2.9)×106 𝜓(3686) events collected with the BESIII detector. The decay channel ℎ𝑐→𝐾+𝐾−𝜋+𝜋−𝜋0 is observed for the first time and has a measured significance of 6.0𝜎. The corresponding branching fraction is determined to be ℬ(ℎ𝑐→𝐾+𝐾−𝜋+𝜋−𝜋0)=(3.3±0.6±0.6)×10−3 (where the uncertainties are statistical and systematic, respectively). Evidence for the decays ℎ𝑐→𝜋+𝜋−𝜋0𝜂 and ℎ𝑐→𝐾0𝑆𝐾±𝜋∓𝜋+𝜋− is found with a significance of 3.6𝜎 and 3.8𝜎, respectively. The corresponding branching fractions (and upper limits) are obtained to be ℬ(ℎ𝑐→𝜋+𝜋−𝜋0𝜂)=(7.2±1.8±1.3)×10−3 (<1.8×10−2) and ℬ(ℎ𝑐→𝐾0𝑆𝐾±𝜋∓𝜋+𝜋−)=(2.8±0.9±0.5)×10−3 (<4.7×10−3). Upper limits on the branching fractions for the final states ℎ𝑐→𝐾+𝐾−𝜋0, 𝐾+𝐾−𝜂, 𝐾+𝐾−𝜋+𝜋−𝜂, 2(𝐾+𝐾−)𝜋0, 𝐾+𝐾−𝜋0𝜂, 𝐾0𝑆𝐾±𝜋∓, and 𝑝¯𝑝𝜋0𝜋0 are determined at a confidence level of 90%.
A search for invisible decays of the Λ baryon is carried out in the process 𝐽/𝜓→Λ¯Λ based on (1.0087±0.0044)×1010 𝐽/𝜓 events collected with the BESIII detector located at the BEPCII storage ring. No signals are found for the invisible decays of Λ baryon, and the upper limit of the branching fraction is determined to be 7.4×10−5 at the 90% confidence level. This is the first search for invisible decays of baryons; such searches will play an important role in constraining dark sector models related to the baryon asymmetry.
Based on an 𝑒+𝑒− collision data sample corresponding to an integrated luminosity of 567 pb−1 taken at the center-of-mass energy of √𝑠=4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay Λ+𝑐→Λ+𝑋 to be ℬ(Λ+𝑐→Λ+𝑋)=(38.2+2.8−2.2±0.9)% using the double-tag method, where 𝑋 refers to any possible final state particles. In addition, we search for direct 𝐶𝑃 violation in the charge asymmetry of this inclusive decay for the first time, and obtain 𝒜𝐶𝑃≡[ℬ(Λ+𝑐→Λ+𝑋)−ℬ(¯Λ−𝑐 → ¯Λ+𝑋)]/[ℬ(Λ+𝑐→Λ+𝑋)+ℬ(¯Λ−𝑐 → ¯Λ+𝑋)]=(2.1+7.0−6.6±1.6)%, a statistically limited result with no evidence of 𝐶𝑃 violation.
Using a low background data sample of 9.7×105 𝐽/𝜓→𝛾𝜂′, 𝜂′→𝛾𝜋+𝜋− events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII detector at BEPCII, the decay dynamics of 𝜂′→𝛾𝜋+𝜋− are studied with both model-dependent and model-independent approaches. The contributions of 𝜔 and the 𝜌(770)−𝜔 interference are observed for the first time in the decays 𝜂′→𝛾𝜋+𝜋− in both approaches. Additionally, a contribution from the box anomaly or the 𝜌(1450) resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach.
Using a data sample of 𝑒+𝑒− collisions corresponding to an integrated luminosity of 567 pb−1 collected at a center-of-mass energy of √𝑠=4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Λ+𝑐 decay with a double-tag method. We obtain ℬ(Λ+𝑐→𝑋𝑒+𝜈𝑒)=(3.95±0.34±0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Λ+𝑐 lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (𝐷0 and 𝐷+), we obtain the ratio of the inclusive semileptonic decay widths Γ(Λ+𝑐→𝑋𝑒+𝜈𝑒)/¯Γ(𝐷→𝑋𝑒+𝜈𝑒)=1.26±0.12.
The Born cross section of the process e+e−→ηJ/ψ at a center-of-mass energy s√=3.773 GeV is measured to be (8.89±0.88±0.42) pb, using a data sample collected with the BESIII detector operating at the BEPCII storage ring. The decay ψ(3770)→ηJ/ψ is observed for the first time with a statistical significance of 7.4σ. From a fit to the dressed cross-section line-shape of e+e−→ηJ/ψ from s√=3.773 to 4.600 GeV we obtain the branching fraction of the decay ψ(3770)→ηJ/ψ to be (11.6±6.1±1.0)×10−4 when the ψ(3770) decay amplitude is added coherently to the other contributions, and (7.9±1.0±0.7)×10−4 when it is added incoherently. Here the first uncertainties are statistical and the second are systematic.
Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, the Born cross section of the process 𝑒+𝑒−→𝜂𝐽/𝜓 at a center-of-mass energy √𝑠=3.773 GeV is measured to be (8.88±0.87±0.42) pb. We fit the cross section line shape before correcting for the initial state radiation from √𝑠=3.773 to 4.600 GeV to obtain the branching fraction ℬ(𝜓(3770)→𝜂𝐽/𝜓). We obtain ℬ(𝜓(3770)→𝜂𝐽/𝜓)=(11.3±5.9±1.1)×10−4 when the 𝜓(3770) decay amplitude is added coherently to the other contributions, and (8.7±1.0±0.8)×10−4 when it is added incoherently. Here the quoted uncertainties are statistical and systematic, respectively. In both cases, the statistical significance of 𝜓(3770) resonance is above 7𝜎. This is the first time the decay 𝜓(3770)→𝜂𝐽/𝜓 is observed with a statistical significance greater than 5𝜎.
By analyzing 4.48×108 ψ(3686) events collected with the BESIII detector, we observe the decays χcJ→nK0SΛ¯+c.c. (J=0, 1, 2) for the first time, via the radiative transition ψ(3686)→γχcJ. The branching fractions are determined to be (6.67±0.26stat±0.41syst)×10−4, (1.71±0.12stat±0.12syst)×10−4, and (3.66±0.17stat±0.23syst)×10−4 for J=0, 1, and 2, respectively.
Using a dedicated data sample taken in 2018 on the J/ψ peak, we perform a detailed study of the trigger efficiencies of the BESIII detector. The efficiencies are determined from three representative physics processes, namely Bhabha scattering, dimuon production and generic hadronic events with charged particles. The combined efficiency of all active triggers approaches 100% in most cases, with uncertainties small enough not to affect most physics analyses.
The decays of χc2→K+K−π0, KSK±π∓ and π+π−π0 are studied with the ψ(3686) data samples collected with the Beijing Spectrometer (BESIII). For the first time, the branching fractions of χc2→K∗K¯¯¯¯¯, χc2→a±2(1320)π∓/a02(1320)π0 and χc2→ρ(770)±π∓ are measured. Here K∗K¯¯¯¯¯ denotes both K∗±K∓ and K∗0K¯¯¯¯¯0+c.c., and K∗ denotes the resonances K∗(892), K∗2(1430) and K∗3(1780). The observations indicate a strong violation of the helicity selection rule in χc2 decays into vector and pseudoscalar meson pairs. The measured branching fractions of χc2→K∗(892)K¯¯¯¯¯ are more than 20 times larger than that of χc2→ρ(770)±π∓, which implies the effects are largely due to U-spin symmetry breaking, rather than just isospin symmetry breaking in charmonium decays.
The decays of χc2→K+K−π0, KSK±π∓ and π+π−π0 are studied with the ψ(3686) data samples collected with the Beijing Spectrometer (BESIII). For the first time, the branching fractions of χc2→K∗K¯¯¯¯¯, χc2→a±2(1320)π∓/a02(1320)π0 and χc2→ρ(770)±π∓ are measured. Here K∗K¯¯¯¯¯ denotes both K∗±K∓ and K∗0K¯¯¯¯¯0+c.c., and K∗ denotes the resonances K∗(892), K∗2(1430) and K∗3(1780). The observations indicate a strong violation of the helicity selection rule in χc2 decays into vector and pseudoscalar meson pairs. The measured branching fractions of χc2→K∗(892)K¯¯¯¯¯ are more than 10 times larger than the upper limit of χc2→ρ(770)±π∓, which is so far the first direct observation of a significant U-spin symmetry breaking effect in charmonium decays.
The decays of χc2→K+K−π0, KSK±π∓ and π+π−π0 are studied with the ψ(3686) data samples collected with the Beijing Spectrometer (BESIII). For the first time, the branching fractions of χc2→K∗K¯¯¯¯¯, χc2→a±2(1320)π∓/a02(1320)π0 and χc2→ρ(770)±π∓ are measured. Here K∗K¯¯¯¯¯ denotes both K∗±K∓ and K∗0K¯¯¯¯¯0+c.c., and K∗ denotes the resonances K∗(892), K∗2(1430) and K∗3(1780). The observations indicate a strong violation of the helicity selection rule in χc2 decays into vector and pseudoscalar meson pairs. The measured branching fractions of χc2→K∗(892)K¯¯¯¯¯ are more than 20 times larger than that of χc2→ρ(770)±π∓, which implies the effects are largely due to U-spin symmetry breaking, rather than just isospin symmetry breaking in charmonium decays.
Based on a data sample of (1.0087±0.0044)×1010 𝐽/𝜓 events collected by the BESIII detector at the BEPCII accelerator, the absolute branching fraction (BF) of the decay 𝐽/𝜓→𝛾𝜂 is measured with high precision using events in which the radiative photon converts to 𝑒+𝑒−. Using the measured absolute BF of 𝐽/𝜓→𝛾𝜂, the absolute BFs of four dominant 𝜂 decay modes are measured for the first time. The results are ℬ(𝐽/𝜓→𝛾𝜂)=(1.067±0.005±0.023)×10−3, ℬ(𝜂→𝛾𝛾)=(39.86±0.04±0.99)%, ℬ(𝜂→𝜋0𝜋0𝜋0)=(31.96±0.07±0.84)%, ℬ(𝜂→𝜋+𝜋−𝜋0)=(23.04±0.03±0.54)%, and ℬ(𝜂→𝜋+𝜋−𝛾)=(4.38±0.02±0.10)%, where the first and second uncertainties are statistical and systematic, respectively. The results are consistent with the world average values within two standard deviations.
Based on a data sample of (1.0087+-0.0044)x10^10 Jpsi events collected by the BESIII detector at the BEPCII accelerator, the absolute branching fraction (BF) of the decay Jpsi->gamma eta is measured with high precision using events in which the radiative photon converts to e+e-. Using the measured absolute BF of Jpsi->gamma eta, the absolute BFs of four dominant eta decay modes are measured for the first time. The results are B(Jpsi->gamma eta) = (1.067+-0.005+-0.023)x10^-3, B(eta->gamma gamma) = (39.86+-0.04+-0.99)%, B(eta->pi0pi0pi0) = (31.96+-0.07+-0.84)%, B(eta->pi+pi-pi0) = (23.04+-0.03+-0.54)%, and B(eta->pi+pi-gamma) = (4.38+-0.02+-0.10)%, where the first and second uncertainties are statistical and systematic, respectively. The results are consistent with the world average values within two standard deviations.
The decays of χc2→K+K−π0, KSK±π∓ and π+π−π0 are studied with the ψ(3686) data samples collected with the Beijing Spectrometer (BESIII). For the first time, the branching fractions of χc2→K∗K¯¯¯¯¯, χc2→a±2(1320)π∓/a02(1320)π0 and χc2→ρ(770)±π∓ are measured. Here K∗K¯¯¯¯¯ denotes both K∗±K∓ and K∗0K¯¯¯¯¯0+c.c., and K∗ denotes the resonances K∗(892), K∗2(1430) and K∗3(1780). The observations indicate a strong violation of the helicity selection rule in χc2 decays into vector and pseudoscalar meson pairs. The measured branching fractions of χc2→K∗(892)K¯¯¯¯¯ are more than 10 times larger than the upper limit of χc2→ρ(770)±π∓, which is so far the first direct observation of a significant U-spin symmetry breaking effect in charmonium decays.
Using a data sample of 448.1×106 𝜓(3686) events collected with the BESIII detector operating at the BEPCII, we perform search for the hadronic transition ℎ𝑐→𝜋+𝜋−𝐽/𝜓 via 𝜓(3686)→𝜋0ℎ𝑐. No signals of the transition are observed, and the upper limit on the product branching fraction ℬ(𝜓(3686)→𝜋0ℎ𝑐)ℬ(ℎ𝑐→𝜋+𝜋−𝐽/𝜓) at the 90% confidence level (C.L.) is determined to be 2.0×10−6. This is the most stringent upper limit to date.
Using 2.93fb−1 of e+e− collision data collected at a center-of-mass energy of 3.773\,GeV with the BESIII detector, we present a measurement of the branching fraction of the doubly Cabibbo-suppressed (DCS) decay D0→K+π−π0 and a search for the DCS decay D0→K+π−π0π0. The branching fraction of D0→K+π−π0 is determined to be [3.13+0.60−0.56(stat)±0.09(syst)]×10−4. No signal is observed for D0→K+π−π0π0 and an upper limit of 3.6×10−4 is set on the branching fraction at the 90\% C.L. We combine these results with the world-average branching fractions of their counterpart Cabibbo-favored decays to determine the ratios of the doubly Cabibbo-suppressed over the Cabibbo-favored branching fractions, B(D0→K+π−π0)/B(D0→K−π+π0)=(0.22±0.04)%~and B(D0→K+π−π0π0)/B(D0→K−π+π0π0)<0.40% at the 90\% C.L., which correspond to (0.75±0.14)tan4θC~and 1.37×tan4θC, respectively, where θC is the Cabibbo angle.
Based on an 𝑒+𝑒− collision data sample corresponding to an integrated luminosity of 2.93 fb−1 collected with the BESIII detector at √𝑠=3.773 GeV, the first amplitude analysis of the singly Cabibbo-suppressed decay 𝐷+→𝐾+𝐾0𝑆𝜋0 is performed. From the amplitude analysis, the 𝐾*(892)+𝐾0𝑆 component is found to be dominant with a fraction of (57.1±2.6±4.2)%, where the first uncertainty is statistical and the second systematic. In combination with the absolute branching fraction ℬ(𝐷+→𝐾+𝐾0𝑆𝜋0) measured by BESIII, we obtain ℬ(𝐷+→𝐾*(892)+𝐾0𝑆)=(8.69±0.40±0.64±0.51)×10−3, where the third uncertainty is due to the branching fraction ℬ(𝐷+→𝐾+𝐾0𝑆𝜋0). The precision of this result is significantly improved compared to the previous measurement. This result also differs from most of theoretical predictions by about 4𝜎, which may help to improve the understanding of the dynamics behind.
The Born cross sections and effective form factors for process 𝑒+𝑒−→Ξ−¯Ξ+ are measured at eight center-of-mass energies between 2.644 and 3.080 GeV, using a total integrated luminosity of 363.9 pb−1 𝑒+𝑒− collision data collected with the BESIII detector at BEPCII. After performing a fit to the Born cross section of 𝑒+𝑒−→Ξ−¯Ξ+, no significant threshold effect is observed.
We present the first experimental search for the rare charm decay D0→π0ν¯ν. It is based on an e+e− collision sample consisting of 10.6×10^6 pairs of D0¯D0 mesons collected by the BESIII detector at √s=3.773 GeV, corresponding to an integrated luminosity of 2.93 fb^−1. A data-driven method is used to ensure the reliability of the background modeling. No significant D0→π0ν¯ν signal is observed in data and an upper limit of the branching fraction is set to be 2.1×10^-4 at the 90% confidence level. This is the first experimental constraint on charmed-hadron decays into dineutrino final states.
The Born cross sections for the process e+e−→η′π+π− at different center-of-mass energies between 2.00 and 3.08 GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of 6.3σ and a mass and width of M=(2111±43±25)~MeV/c2 and Γ=(135±34±30)~MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in e+e−→η′π+π− and BESIII in e+e−→ωπ0 within two standard deviations.
Using data taken at 23 center-of-mass energies between 4.0 and 4.6 GeV with the BESIII detector at the BEPCII collider and with a total integrated luminosity of approximately 15 fb−1, the process e+e−→2(pp¯) is studied for the first time. The Born cross sections for e+e−→2(pp¯) are measured, and no significant structure is observed in the lineshape. The baryon pair (pp and p¯p¯) invariant mass spectra are consistent with phase space, therefore no hexaquark or di-baryon state is found.
Using data taken at 23 center-of-mass energies between 4.0 and 4.6 GeV with the BESIII detector at the BEPCII collider and with a total integrated luminosity of approximately 15 fb−1, the process e+e−→2(pp¯) is studied for the first time. The Born cross sections for e+e−→2(pp¯) are measured, and no significant structure is observed in the lineshape. The baryon pair (pp and p¯p¯) invariant mass spectra are consistent with phase space, therefore no hexaquark or di-baryon state is found.
The Born cross sections for the process e+e−→η′π+π− at different center-of-mass energies between 2.00 and 3.08~GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of 6.3σ and a mass and width of M=(2108±46±25)~MeV/c2 and Γ=(138±36±30)~MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in e+e−→η′π+π− and BESIII in e+e−→ωπ0 within two standard deviations.
The Born cross sections for the process e+e−→η′π+π− at different center-of-mass energies between 2.00 and 3.08~GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of 6.3σ and a mass and width of M=(2108±46±25)~MeV/c2 and Γ=(138±36±30)~MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in e+e−→η′π+π− and BESIII in e+e−→ωπ0 within two standard deviations.
The singly Cabibbo-suppressed decay Λ+c→nπ+ is observed for the first time with a statistical significance of 7.3σ by using 3.9 fb−1 of e+e− collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ+c→nπ+ is measured to be (6.6±1.2stat±0.4syst)×10−4. By taking the upper limit of branching fractions of Λ+c→pπ0 from the Belle experiment, the ratio of branching fractions between Λ+c→nπ+ and Λ+c→pπ0 is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with the current predictions of available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ+c→Λπ+ and Λ+c→Σ0π+ are measured to be (1.31±0.08stat±0.05syst)×10−2 and (1.22±0.08stat±0.07syst)×10−2, respectively, which are consistent with previous results.
The singly Cabibbo-suppressed decay Λ+c→nπ+ is observed for the first time with a statistical significance of 7.3σ by using 3.9 fb−1 of e+e− collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ+c→nπ+ is measured to be (6.6±1.2stat±0.4syst)×10−4. By taking the upper limit of branching fractions of Λ+c→pπ0 from the Belle experiment, the ratio of branching fractions between Λ+c→nπ+ and Λ+c→pπ0 is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with the current predictions of available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ+c→Λπ+ and Λ+c→Σ0π+ are measured to be (1.31±0.08stat±0.05syst)×10−2 and (1.22±0.08stat±0.07syst)×10−2, respectively, which are consistent with previous results.
The singly Cabibbo-suppressed decay Λ+c→nπ+ is observed for the first time with a statistical significance of 7.3σ by using 3.9 fb−1 of e+e− collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ+c→nπ+ is measured to be (6.6±1.2stat±0.4syst)×10−4. By taking the upper limit of branching fractions of Λ+c→pπ0 from the Belle experiment, the ratio of branching fractions between Λ+c→nπ+ and Λ+c→pπ0 is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with the current predictions of available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ+c→Λπ+ and Λ+c→Σ0π+ are measured to be (1.31±0.08stat±0.05syst)×10−2 and (1.22±0.08stat±0.07syst)×10−2, respectively, which are consistent with previous results.
To study the nature of the state Y (2175), a dedicated data set of e+e− collision data was collected at the center-of-mass energy of 2.125 GeV with the BESIII detector at the BEPCII collider. By analyzing large-angle Bhabha scattering events, the integrated luminosity of this data set is determined to be 108.49±0.02±0.85 pb−1, where the first uncertainty is statistical and the second one is systematic. In addition, the center-of-mass energy of the data set is determined with radiative dimuon events to be 2126.55±0.03±0.85 MeV, where the first uncertainty is statistical and the second one is systematic.
Utilizing the data set corresponding to an integrated luminosity of 3.19 fb−1 collected by the BESIII detector at a center-of-mass energy of 4.178 GeV, we perform an amplitude analysis of the D+s→π+π−π+ decay. The sample contains 13,797 candidate events with a signal purity of ∼80%. We use a quasi-model-independent approach to measure the magnitude and phase of the D+s→π+π−π+ decay, where the P and D waves are parameterized by a sum of three Breit-Wigner amplitudes ρ(770)0, ρ(1450)0, and f2(1270). The fit fractions of different decay channels are also reported.
Utilizing the data set corresponding to an integrated luminosity of 3.19 fb−1 collected by the BESIII detector at a center-of-mass energy of 4.178 GeV, we perform an amplitude analysis of the D+s→π+π−π+ decay. The sample contains 13,797 candidates with a signal purity of ∼80%. The amplitude and phase of the contributing ππ S wave are measured based on a quasi-model-independent approach, along with the amplitudes and phases of the P and D waves parametrized by Breit-Wigner models. The fit fractions of different intermediate decay channels are also reported.
Utilizing the data set corresponding to an integrated luminosity of 3.19 fb−1 collected by the BESIII detector at a center-of-mass energy of 4.178 GeV, we perform an amplitude analysis of the 𝐷+
𝑠→𝜋+𝜋−𝜋+ decay. The sample contains 13,797 candidates with a signal purity of ∼80%. The amplitude and phase of the contributing 𝜋𝜋 𝒮 wave are measured based on a quasi-model-independent approach, along with the amplitudes and phases of the 𝒫 and 𝒟 waves parametrized by Breit-Wigner models. The fit fractions of different intermediate decay channels are also reported.
The baryonic decay D+s→pn¯ is observed, and the corresponding branching fraction is measured to be (1.21±0.10±0.05)×10−3, where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e+e− double-ring collider with a center-of-mass energy of 4.178~GeV and an integrated luminosity of 3.19~fb−1. The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision, which may deepen our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays.
We search for rare decays of D mesons to hadrons accompany with an electron-positron pair (h(h')e+e−), using an e+e− collision sample corresponding to an integrated luminosity of 2.93 fb−1 collected with the BESIII detector at s√ = 3.773 GeV. No significant signals are observed, and the corresponding upper limits on the branching fractions at the 90% confidence level are determined. The sensitivities of the results are at the level of 10−5∼10−6, providing a large improvement over previous searches.
Measurement of e⁺e⁻ → KK̄J/ψ cross sections at center-of-mass energies from 4.189 to 4.600 GeV
(2018)
We investigate the process e+e−→KK¯J/ψ at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb−1 of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions e+e−→K+K−J/ψ and K0SK0SJ/ψ are measured as a function of center-of-mass energy. The energy dependence of the cross section for e+e−→K+K−J/ψ is shown to differ from that for π+π−J/ψ in the region around the Y(4260). In addition, there is evidence for a structure around 4.5 GeV in the e+e−→K+K−J/ψ cross section that is not present in π+π−J/ψ.
Based on a data sample of (448.1±2.9)×106 ψ(3686) decays collected with the BESIII experiment, a search for the flavor changing neutral current transition ψ(3686) → Λ+cp¯¯¯e+e−+c.c. is performed for the first time. No signal candidates are observed and the upper limit on the branching fraction of ψ(3686) → Λ+cp¯¯¯e+e− is determined to be 1.7×10−6 at the 90\% confidence level. The result is consistent with expectations from the Standard Model, and no evidence for new physics is found.
Using a data sample of (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector at the BEPCII collider, we present measurements of branching fractions for the decays χcJ→Σ+Σ¯− and Σ0Σ¯0. The decays χc1,2→Σ+Σ¯− and Σ0Σ¯0 are observed for the first time, and the branching fractions for χc0→Σ+Σ¯− and Σ0Σ¯0 decays are measured with improved precision. The branching fraction ratios between the charged and neutral modes are consistent with the prediction of isospin symmetry.
Using data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.178 to 4.600 GeV, we study the process eþe− → π0Xð3872Þγ and search for Zcð4020Þ0 → Xð3872Þγ. We find no significant signal and set upper limits on σðeþe− → π0Xð3872ÞγÞ · BðXð3872Þ → πþπ−J=ψÞ and σðeþe− → π0Zcð4020Þ0Þ · BðZcð4020Þ0 → Xð3872ÞγÞ · BðXð3872Þ → πþπ−J=ψÞ for each energy point at 90% confidence level, which is of the order of several tenths pb.
By analyzing an e+e− annihilation data sample with an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, we determine the absolute branching fractions of the hadronic decays D0→K−π+ω, D0→K0Sπ0ω, and D+→K0Sπ+ω to be (3.392±0.044stat±0.085syst)%, (0.848±0.046stat±0.031syst)%, and (0.707±0.041stat±0.029syst)%, respectively. The accuracy of the branching fraction measurement of the decay D0→K−π+ω is improved by a factor of seven compared to the world average value. The D0→K0Sπ0ω and D+→K0Sπ+ω decays are observed for the first time.
Study of the decay Dₛ⁺ → π⁺π⁺π⁻η and observation of the W-annihilation decay Dₛ⁺ → a₀(980)⁺ρ⁰
(2021)
The decay 𝐷+𝑠→𝜋+𝜋+𝜋−𝜂 is observed for the first time, using 𝑒+𝑒− collision data corresponding to an integrated luminosity of 6.32 fb−1, collected by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV. The absolute branching fraction for this decay is measured to be ℬ(𝐷+𝑠→𝜋+𝜋+𝜋−𝜂)=(3.12±0.13stat±0.09syst)%. The first amplitude analysis of this decay reveals the substructures in 𝐷+𝑠→𝜋+𝜋+𝜋−𝜂 and determines the relative fractions and the phases among these substructures. The dominant intermediate process is 𝐷+𝑠→𝑎1(1260)+𝜂,𝑎1(1260)+→𝜌(770)0𝜋+ with a branching fraction of (1.73±0.14stat±0.08syst)%. We also observe the 𝑊-annihilation process 𝐷+𝑠→𝑎0(980)+𝜌(770)0, 𝑎0(980)+→𝜋+𝜂 with a branching fraction of (0.21±0.08stat±0.05syst)%, which is larger than the branching fractions of other measured pure 𝑊-annihilation decays by 1 order of magnitude.