Refine
Year of publication
Document Type
- Preprint (836)
- Article (689)
- Conference Proceeding (4)
- Doctoral Thesis (1)
- Working Paper (1)
Language
- English (1524)
- German (6)
- Multiple languages (1)
Has Fulltext
- yes (1531)
Is part of the Bibliography
- no (1531)
Keywords
- Heavy Ion Experiments (20)
- e +-e − Experiments (14)
- BESIII (12)
- Hadron-Hadron Scattering (11)
- Hadron-Hadron scattering (experiments) (11)
- Branching fraction (9)
- LHC (9)
- Particle and Resonance Production (9)
- Charm Physics (6)
- Heavy-ion collision (6)
- Spectroscopy (6)
- HIV (5)
- Quarkonium (5)
- ALICE experiment (4)
- Charm physics (4)
- Collective Flow (4)
- Electroweak interaction (4)
- Exotics (4)
- Inverse kinematics (4)
- Jets (4)
- Lepton colliders (4)
- Osteoporosis (4)
- Quark-Gluon Plasma (4)
- Quasi-free scattering (4)
- ALICE (3)
- Biomarkers (3)
- Bone density (3)
- COVID-19 (3)
- Charmed mesons (3)
- Experimental nuclear physics (3)
- Experimental particle physics (3)
- Hadronic decays (3)
- Heavy Ions (3)
- Jets and Jet Substructure (3)
- Oncology (3)
- Particle and resonance production (3)
- QCD (3)
- Spectroscopic factors (3)
- Spine (3)
- breast cancer (3)
- e+-e− Experiments (3)
- pp collisions (3)
- Antiretroviral therapy (2)
- Beauty production (2)
- Branching fractions (2)
- CT (2)
- Charmonium (2)
- Cirrhosis (2)
- Computed tomography (2)
- Diagnostic markers (2)
- Diagnostik (2)
- Electroweak Interaction (2)
- Epilepsy (2)
- Flavour Physics (2)
- Früherkennung (2)
- Heart failure (2)
- Heavy Quark Production (2)
- Hypertension (2)
- Inflammation (2)
- Lepton-Nucleon Scattering (experiments) (2)
- Leptonic, semileptonic & radiative decays (2)
- Liver diseases (2)
- Mammakarzinom (2)
- Nachsorge (2)
- Nuclear reactions (2)
- Particle Correlations and Fluctuations (2)
- Particle correlations and fluctuations (2)
- Particle decays (2)
- Pb–Pb collisions (2)
- Radiative decay (2)
- Relativistic heavy-ion collisions (2)
- Richtlinie (2)
- Seizure (2)
- Shell model (2)
- Single electrons (2)
- Single-particle states (2)
- biomarker (2)
- diagnosis (2)
- follow‑up (2)
- guideline (2)
- pelvic packing (2)
- reference values (2)
- screening (2)
- 900 GeV (1)
- ABC transporters (1)
- ALICE detector (1)
- ALK (1)
- APRI (1)
- ATPases (1)
- Absolute branching fraction (1)
- Accelerators & Beams (1)
- Accelerators & storage rings (1)
- Acute coronary syndrome (1)
- Alpha-synuclein (1)
- Angiography (1)
- Angiomyolipoma (1)
- Anti-nuclei (1)
- Anti-seizure medication (1)
- Anticonvulsant (1)
- Antiretrovirals (1)
- Antirheumatic agents (1)
- Antiviral therapy (1)
- Aortic valve (1)
- Apoptosis (1)
- Artesunate (1)
- Atherosclerosis (1)
- Atomic & molecular beams (1)
- Atomic, Molecular & Optical (1)
- Atrial fibrillation (1)
- B cell receptor (1)
- B cell subpopulations (1)
- BESIII detector (1)
- BRCA1 (1)
- BRCA2 (1)
- Bacterial genomics (1)
- Bayesian inference (1)
- Beam loss (1)
- Bhabha (1)
- Biomarker (1)
- Bipolar disorder (1)
- Bleeding (1)
- Blood plasma (1)
- Blood pressure (1)
- Body mass index (1)
- Bone diseases (1)
- Bone diseases, Metabolic (1)
- Boosted Jets (1)
- Born cross section (1)
- Born cross section measurement (1)
- Branching fraction measurement (1)
- Breast cancer (1)
- C-clamp (1)
- C3M (1)
- C4M (1)
- CD16 (1)
- CD56 (1)
- COVID 19 (1)
- CP violation (1)
- CRPC (1)
- CT dual-energy computed tomography (1)
- CVID (1)
- Cancer (1)
- Cancer treatment (1)
- Cardiac implantable electronic devices (1)
- Cardiac rehabilitation (1)
- Cardiac resynchronization therapy (1)
- Cardiac troponin (1)
- Cardiology (1)
- Cardiovascular biology (1)
- Cardiovascular disease risk (1)
- Cardiovascular diseases (1)
- Cell-to-Cell Spread (1)
- Centrality Class (1)
- Centrality Selection (1)
- Charge fluctuations (1)
- Charge-transfer collisions (1)
- Charm vector (1)
- Charmed baryon (1)
- Charmonium (-like) (1)
- Chemoradiotherapy (1)
- Child (1)
- Children (1)
- Chronic obstructive pulmonary disease (1)
- Circular accelerators (1)
- Clinical study (1)
- Clinical variation (1)
- Cohort studies (1)
- Collagen Maps (1)
- Collective Flow, (1)
- Comparative effectiveness research (1)
- Comparison with QCD (1)
- Complex II (1)
- Computed tomography, X-ray (1)
- Consensus (1)
- Consensus document (1)
- Contrast agent (1)
- Costs (1)
- Cross section (1)
- Cross sections (1)
- Culture positive (1)
- D meson (1)
- DECT (1)
- Dark photon (1)
- Dark sector (1)
- De-isolation (1)
- Death rates (1)
- Dermatomyositis (1)
- Diagnosis (1)
- Diagnostic differentiation (1)
- Digestive system procedures (1)
- Direct nuclear reactions (1)
- Direct reactions (1)
- Docetaxel (1)
- Drug screens (1)
- Dual-energy computed tomography (1)
- Economics (1)
- Effective form factor (1)
- Eicosanoids (1)
- Ejection fraction (1)
- Elderly (1)
- Electromagnetic form factor (1)
- Electromagnetic form factors (1)
- Electron-pion identification (1)
- Electronic transitions (1)
- Elliptic flow (1)
- Endocrinology (1)
- Endoscopy (1)
- Ephrin-B2–EphB4 (1)
- Esophagectomy (1)
- Europe (1)
- European Society for Immunodeficiencies (ESID) (1)
- Everolimus (1)
- Exercise training (1)
- Exosomes (1)
- FAPI PET (1)
- FIB-4 (1)
- FOS: Physical sciences (1)
- Falciparum (1)
- Fatty acids (1)
- Fatty liver (1)
- Femtoscopy (1)
- Fibre/foam sandwich radiator (1)
- Fibrosis (1)
- Fibrotest (1)
- First-line combination antiretroviral therapy (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Form factors (1)
- Forschung (1)
- Frailty (1)
- Gadobutrol (1)
- Gadopentate dimeglumine (1)
- General practitioners (1)
- Genetics (1)
- German PID-NET registry (1)
- Gleason Grade Group (1)
- HBT (1)
- HBV (1)
- HCV (1)
- HER2-positive (1)
- HIV-1 (1)
- HNO (1)
- Hadron production (1)
- Hadron-Hadron Scattering Heavy (1)
- Hadron-hadron interactions (1)
- Hals-Nasen-Ohren-Heilkunde (1)
- Hard Scattering (1)
- Health economics (1)
- Heavy Ion Experiment (1)
- Heavy flavor production (1)
- Heavy flavour production (1)
- Heavy ion storage ring (1)
- Heavy ions (1)
- Heavy-flavour decay muons (1)
- Heavy-flavour production (1)
- Heavy-ion collisions (1)
- Helicity amplitude analysis (1)
- Hematology (1)
- Hepatitis B virus (1)
- Hepatitis C virus (1)
- Hepatocellular carcinoma (1)
- Hepatotoxicity (1)
- Hereditary breast and ovarian cancer (1)
- Herniated disk (1)
- High Energy Physics - Experiment (hep-ex) (1)
- High-energy neutron detection (1)
- Human behaviour (1)
- Hyperons (1)
- ICL (1)
- ICL V4c (1)
- INR (1)
- IgG substitution therapy (1)
- Image processing (1)
- Implantable cardioverter-defibrillator (1)
- In-TIPS thrombosis (1)
- Inclusive branching fraction (1)
- Inclusive spectra (1)
- Initial state radiation (1)
- Intensity interferometry (1)
- International normalized ratio (1)
- Intervertebral disc displacement (1)
- Invariant Mass Distribution (1)
- Invisible decays (1)
- Ionisation energy loss (1)
- Isoscalar giant resonances (1)
- Jet Physics (1)
- Jet Substructure (1)
- K0S (1)
- Kidney diseases (1)
- Lehre (1)
- Leukemias (1)
- Liver (1)
- Liver enzymes (1)
- Liver fibrosis (1)
- Liver transplantation (1)
- Long non-coding RNAs (1)
- Low & intermediate-energy accelerators (1)
- Lumbar Disk Degeneration (1)
- MHC (1)
- MRI (1)
- MTOR inhibitor (1)
- MYCN amplification (1)
- Malaria (1)
- Masquelet technique (1)
- Material budget (1)
- MicroRNAs (1)
- Mid-rapidity (1)
- Minimum Bias (1)
- Mitochondria (1)
- Molecular diagnostic testing (1)
- Molecular neuroscience (1)
- Monte Carlo (1)
- Multi-Parton Interactions (1)
- Multi-neutron detection (1)
- Multi-strange baryons (1)
- Multi-wire proportional drift chamber (1)
- Multivariate analysis (1)
- Mycobacteria (1)
- Mycobacterium avium complex (1)
- Myocardial infarction (1)
- Myopia (1)
- NK cells (1)
- NMR spectroscopy (1)
- Nanoscale biophysics (1)
- Neoadjuvant radiochemotherapy (1)
- Neoadjuvant therapy (1)
- Neural network (1)
- Neutrinos (1)
- Non-small cell lung cancer (1)
- Noninferiority (1)
- Nontuberculous mycobacteria (1)
- Nuclear astrophysics (1)
- Nuclear modification factor (1)
- Nuclear physics of explosive environments (1)
- Nuclear structure & decays (1)
- Nucleon induced nuclear reactions (1)
- ORL (1)
- Oesophagogastric cancer oxaliplatin (1)
- Oldest-old (1)
- One-nucleon removal (1)
- Open pulmonary tuberculosis (1)
- Opportunistic infections (1)
- Optical tweezers (1)
- Orbital electron capture (1)
- Osteoporotic fractures (1)
- Otorhinolaryngology (1)
- Oxidative phosphorylation (1)
- PDE‐5‐inhibitor (1)
- PID prevalence (1)
- PYTHIA (1)
- Pacemaker (1)
- Parkinson’s disease (1)
- Particle phenomena (1)
- Pathological complete response (1)
- Pb–Pb (1)
- Percutaneous (1)
- Personalized medicine (1)
- Phakic (1)
- Phantoms (imaging) (1)
- Phospholipids (1)
- Photon counting (1)
- Physical activity (1)
- Plasmodium (1)
- Plastic scintillator array (1)
- Point-of-care testing (1)
- Polarization (1)
- Post-processing (1)
- Pre-treatment drug resistance mutations (1)
- Predictive markers (1)
- Prevention (1)
- Production Cross Section (1)
- Prognosis (1)
- Properties of Hadrons (1)
- Protease inhibitor therapy (1)
- Proton (1)
- Proton–proton (1)
- Pseudarthrosis (1)
- Psychiatric disorders (1)
- QGP (1)
- Quantitative Imaging (1)
- Quantum chromodynamics (1)
- Quark Deconfinement (1)
- Quark Gluon Plasma (1)
- Quark Production (1)
- Quark gluon plasma (1)
- Quinine (1)
- RAS pathway (1)
- Radiative capture (1)
- Rapidity Range (1)
- Rare decays (1)
- Reactions with relativistic radioactive beams (1)
- Registries (1)
- Regulatory networks (1)
- Relativistic heavy ion physics (1)
- Renal lesions (1)
- Research (1)
- Residency (1)
- Resolution Parameter (1)
- Respiratory infections (1)
- Retinal diseases (1)
- Rhabdomyoma (1)
- SARS CoV 2 (1)
- SARS-CoV-2 (1)
- SARS-CoV‑2 pandemic (1)
- SARS-CoV‑2-Pandemie (1)
- SR-BI (1)
- SVR (1)
- Semi-leptonic decays (1)
- Severe malaria (1)
- Single muons (1)
- Single particle decay spectroscopy (1)
- Sociodemographic characteristics (1)
- Specialist training (1)
- Spectroscopic factors & electromagnetic moments (1)
- Sphingolipids (1)
- Sputum smear-negative (1)
- Stentoplasty (1)
- Storage ring (1)
- Subependymal giant cell astrocytoma (1)
- Super-resolution microscopy (1)
- Surgical oncology (1)
- Systematic Uncertainty (1)
- TB-therapy (1)
- TIPS (1)
- TR (1)
- TSC (1)
- Teaching (1)
- Techniques Electromagnetic calorimeters (1)
- Threshold effect (1)
- Time Projection Chamber (1)
- Tomography (1)
- Tomography (x-ray computed) (1)
- Tracking (1)
- Transferases (1)
- Transient elastography (1)
- Transition radiation detector (1)
- Transjugular Intrahepatic Portosystemic Shunt (1)
- Transverse momentum (1)
- Trigger (1)
- Triple negative (1)
- Triple-negative breast cancer (1)
- Two body weak decay (1)
- Type 2 diabetes (1)
- University hospitals (1)
- Universitätskliniken (1)
- Vector Boson Production (1)
- Vertebral augmentation (1)
- Vertebral body stenting (1)
- Vertebral fracture (1)
- Viral load (1)
- Virological failure (1)
- Virtual noncalcium reconstructions (1)
- Weiterbildung (1)
- X-ray computed (1)
- X-ray crystallography (1)
- Xenon-based gas mixture (1)
- Y states (1)
- accessory proteins (1)
- acoustic radiation force impulse imaging (1)
- acute myeloid leukemia (1)
- adaptive immunity (1)
- adult and elderly patients (1)
- allogeneic transplantation (1)
- angiography (1)
- angiopoietin-like 3 (ANGPTL3) (1)
- annual bleeding rate (1)
- anterior chamber depth changes (1)
- antigen presentation (1)
- auditory system (1)
- autoimmunity (1)
- biopsy cores (1)
- bone marrow derived mononuclear cells (1)
- cART (1)
- cancer therapy (1)
- cardiac magnetic resonance (1)
- castration resistance (1)
- cataract surgery (1)
- cell-free protein synthesis (1)
- center-of-mass energy (1)
- charmonium-like states (1)
- children (1)
- chronic kidney disease (1)
- clinical stage (1)
- co-infection (1)
- cohlear implant (1)
- cohort study (1)
- collagen degradation marker (1)
- component study (1)
- computer-assisted (1)
- critical size defect (1)
- cryo-EM (1)
- cyanines (1)
- cytarabine dose (1)
- dE/dx (1)
- decays (1)
- decision aids (1)
- detector (1)
- dimuon (1)
- dislocation (1)
- e+e − annihilation (1)
- e+e⁻ − Experiments (1)
- e+e− Experiments (1)
- e-scooter (1)
- effective lens position (1)
- effectiveness (1)
- elderly (1)
- electric and acustic stymulation (1)
- electric scooter (1)
- electron-positron collision (1)
- embolization (1)
- erectile dysfunction (1)
- experimental results (1)
- exponential model (1)
- external fixation (1)
- fibrosis imaging (1)
- fibrotest (1)
- flow cytometry (1)
- fracture (1)
- hadron spectroscopy (1)
- hadronic events (1)
- haemophilia A (1)
- head-and-neck cancer (1)
- heavy ion experiments (1)
- heavy-ion storage rings (1)
- helicity amplitude analysis (1)
- hemodynamic instability (1)
- hemorrhage (1)
- hepatitis C (1)
- high-risk neuroblastoma (1)
- immune reconstitution (1)
- inclusive J/ψ decays (1)
- induced membrane (1)
- interoperability (1)
- intrinsically disordered region (1)
- inverse kinematics (1)
- lactate (1)
- lapatinib (1)
- learning loss (1)
- lung cancer (1)
- mTOR inhibitor (1)
- management (1)
- membrane proteins (1)
- metastasis (1)
- metastatic prostate cancer (1)
- mindfulness (1)
- molecular machines (1)
- molecular tug-of-war (1)
- mortality (1)
- myocardial fibrosis (1)
- neoadjuvant therapy (1)
- neutron-induced reactions (1)
- non-ST-segment elevation acute coronary syndrome (1)
- non-invasive fibrosis assessment (1)
- nonstructural proteins (1)
- non‐selective beta‐blocker (1)
- nuclear cardiology (1)
- number of J/ψ events (1)
- oxLDL (1)
- p53 pathway (1)
- pIOL (1)
- pelvic injury (1)
- pelvic ring fracture (1)
- peptide editing (1)
- peptide-loading complex (1)
- photoacid (1)
- phylogeny (1)
- plasma-derived factor VIII concentrate, prophylaxis (1)
- point shear wave elastography (1)
- portal hypertension (1)
- primary active transporters (1)
- primary immunodeficiency (PID) (1)
- proteomics (1)
- proton transfer (1)
- pseudoexfoliative syndrome (1)
- psychotherapy process (1)
- quality control (1)
- quark gluon plasma (1)
- randomized controlled trial (RCT) (1)
- registry for primary immunodeficiency (1)
- resectability (1)
- risk group (1)
- scaffold size (1)
- scar (1)
- school closure (1)
- seed and soil (1)
- sequence alignment (1)
- smart home (1)
- smart living (1)
- spectra (1)
- sphingolipid (1)
- spinal bone metastasis (1)
- spine (1)
- spiro compounds (1)
- stage migration (1)
- structural biology (1)
- structural proteins (1)
- student achievement (1)
- surrogate reactions (1)
- survival (1)
- systematic review (1)
- tapasin (1)
- tetraquark (1)
- therapeutic alliance (1)
- traffic accident (1)
- transient elastography (1)
- transportation (1)
- trastuzumab (1)
- traumatic brain injury (1)
- trigger efficiency (1)
- ultrafast spectroscopy (1)
- vertebroplasty (1)
- web of things (1)
- x-ray techniques (1)
- Λ+c baryon (1)
- Σ hyperon (1)
- ψ(3686) (1)
- √sN N = 2.76 TeV (1)
Institute
- Physik (1393)
- Frankfurt Institute for Advanced Studies (FIAS) (960)
- Informatik (925)
- Medizin (106)
- ELEMENTS (18)
- Geowissenschaften (10)
- Biochemie und Chemie (5)
- Exzellenzcluster Herz-Lungen-System (3)
- Informatik und Mathematik (3)
- Biochemie, Chemie und Pharmazie (2)
The decays D → K−π+π+π− and D → K−π+π 0 are studied in a sample of quantum-correlated DD¯ pairs produced through the process e+e− → ψ(3770) → DD¯, exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb−1 . Here D indicates a quantum superposition of a D0 and a D¯ 0 meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle γ of the Unitarity Triangle in B− → DK− decays at the LHCb and Belle II experiments. The coherence factors are determined to be RK3π = 0.52+0.12−0.10 and RKππ0 = 0.78 ± 0.04, with values for the average strong-phase differences that are δ K3π D = (167+31−19)◦ and δKππ0D = (196+14−15◦ , where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the D → K−π+π+π− to yield results that will allow for a more sensitive measurement of γ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6◦.
We report new measurements of the branching fraction ℬ(𝐷+𝑠→ℓ+𝜈), where ℓ+ is either 𝜇+ or 𝜏+(→𝜋+¯𝜈𝜏), based on 6.32 fb−1 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 𝐷+𝑠→𝜇+𝜈𝜇 and 𝐷+𝑠→𝜏+𝜈𝜏 components yields ℬ(𝐷+𝑠→𝜏+𝜈𝜏)=(5.21±0.25±0.17)×10−2, ℬ(𝐷+𝑠→𝜇+𝜈𝜇)=(5.35±0.13±0.16)×10−3, and the ratio of decay widths 𝑅=Γ(𝐷+𝑠→𝜏+𝜈𝜏)Γ(𝐷+𝑠→𝜇+𝜈𝜇)=9.73+0.61−0.58±0.36, where the first uncertainties are statistical and the second systematic. No evidence of 𝐶𝑃 asymmetry is observed in the decay rates 𝐷±𝑠→𝜇±𝜈𝜇 and 𝐷±𝑠→𝜏±𝜈𝜏: 𝐴𝐶𝑃(𝜇±𝜈)=(−1.2±2.5±1.0)% and 𝐴𝐶𝑃(𝜏±𝜈)=(+2.9±4.8±1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (𝑅=9.75), we find the more precise results ℬ(𝐷+𝑠→𝜏+𝜈𝜏)=(5.22±0.10±0.14)×10−2 and 𝐴𝐶𝑃(𝜏±𝜈𝜏)=(−0.1±1.9±1.0)%. Combining our results with inputs external to our analysis, we determine the 𝑐→¯𝑠 quark mixing matrix element, 𝐷+𝑠 decay constant, and ratio of the decay constants to be |𝑉𝑐𝑠|=0.973±0.009±0.014, 𝑓𝐷+𝑠=249.9±2.4±3.5 MeV, and 𝑓𝐷+𝑠/𝑓𝐷+=1.232±0.035, respectively.
Using 2.93 fb−1 of e+e− collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D0→K1(1270)−e+νe semileptonic decay is presented. The statistical significance of the decay D0→K1(1270)−e+νe is greater than 10σ. The branching fraction of D0→K1(1270)−e+νe is measured to be (1.09±0.13+0.09−0.13±0.12)×10−3. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K1(1270)−→K−π+π−.
Using 2.93 fb−1 of e+e− collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D0→K1(1270)−e+νe semileptonic decay is presented. The statistical significance of the decay D0→K1(1270)−e+νe is greater than 10σ. The branching fraction of D0→K1(1270)−e+νe is measured to be (1.09±0.13+0.09−0.16±0.12)×10−3. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K1(1270)−→K−π+π−. The fraction of longitudinal polarization in D0→K1(1270)−e+νe is determined for the first time to be 0.50±0.19stat±0.08syst.
Using 6.32 fb−1 of 𝑒+𝑒− collision data collected by the BESIII detector at the center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the 𝐷+𝑠→𝐾0𝑆𝐾−𝜋+𝜋+ decays is performed for the first time to determine the intermediate-resonant contributions. The dominant component is the 𝐷+𝑠→𝐾*(892)+¯𝐾*(892)0 decay with a fraction of (40.6±2.9stat±4.9sys)%. Our results of the amplitude analysis are used to obtain a more precise measurement of the branching fraction of the 𝐷+𝑠→𝐾0𝑆𝐾−𝜋+𝜋+ decay, which is determined to be (1.46±0.05stat±0.05sys)%.
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%.
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.
Observation of a near-threshold structure in the K⁺ recoil-mass spectra in e⁺e⁻ → K⁺(Dₛ⁻D*⁰+Dₛ*⁻D⁰)
(2021)
We report a study of the processes of 𝑒+𝑒−→𝐾+𝐷−𝑠𝐷*0 and 𝐾+𝐷*−𝑠𝐷0 based on 𝑒+𝑒− annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb−1. An excess of events over the known contributions of the conventional charmed mesons is observed near the 𝐷−𝑠𝐷*0 and 𝐷*−𝑠𝐷0 mass thresholds in the 𝐾+ recoil-mass spectrum for events collected at √𝑠=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5+1.8
−2.6±2.1) MeV/𝑐2 and (12.8+5.3−4.4±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 𝜎 over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into 𝐷−𝑠𝐷*0 and 𝐷*−𝑠𝐷0. However, the properties of the excess need further exploration with more statistics.
We report a study of the processes of e+e−→K+(D−sD∗0+D∗−sD0) based on e+e− annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb−1. An excess over the known contributions of the conventional charmed mesons is observed near the D−sD∗0 and D∗−sD0 mass thresholds in the K+ recoil-mass spectrum for events collected at s√=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5+1.8−2.6±2.1) MeV/c2 and (12.8+5.3−4.4±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the pure contributions from the conventional charmed mesons. This is the first candidate of the charged hidden-charm tetraquark with strangeness, decaying into D−sD∗0 and D∗−sD0. However, the genuine properties of the excess need further exploration with more statistics.
We report a study of the processes of e+e−→K+(D−sD∗0+D∗−sD0) based on e+e− annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb−1. An excess over the known contributions of the conventional charmed mesons is observed near the D−sD∗0 and D∗−sD0 mass thresholds in the K+ recoil-mass spectrum for events collected at s√=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5+1.8−2.6±2.1) MeV/c2 and (12.8+5.3−4.4±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate of the charged hidden-charm tetraquark with strangeness, decaying into D−sD∗0 and D∗−sD0. However, the properties of the excess need further exploration with more statistics.
he 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.
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=(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 e+e− collision data at ten center-of-mass energies between 2.644 and 3.080 GeV collected with the BESIII detector at BEPCII and corresponding to an integrated luminosity of about 500 pb−1, we measure the cross sections and effective form factors for the process e+e−→Ξ0Ξ¯0 utilizing a single-tag method. A fit to the cross section of e+e−→Ξ0Ξ¯0 with a pQCD-driven power function is performed, from which no significant resonance or threshold enhancement is observed. In addition, the ratio of cross sections for the processes e+e−→Ξ−Ξ¯+ and Ξ0Ξ¯0 is calculated using recent BESIII measurement and is found to be compatible with expectation from isospin symmetry.
Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at a center-of-mass energy of 3.773~GeV, we measure the absolute branching fractions of the decays D0→K−e+νe and D+→K¯0e+νe to be (3.574±0.031stat±0.025syst)% and (8.70±0.14stat±0.16syst)%, respectively. Starting with the process e+e−→DD¯, a new reconstruction method is employed to select events that contain candidates for both D→K¯e+νe and D¯→Ke−ν¯e decays. The branching fractions reported in this work are consistent within uncertainties with previous BESIII measurements that selected events containing D→K¯e+νe and inclusive hadronic D¯ decays. Combining our results with the lifetimes of the D0 and D+ mesons and the previous BESIII measurements leads to a ratio of the two decay partial widths of Γ¯D0→K−e+νeΓ¯D+→K¯0e+νe=1.040±0.021. This ratio supports isospin symmetry in the D0→K−e+νe and D+→K¯0e+νe decays within 1.9σ.
Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at a center-of-mass energy of 3.773 GeV, we measure the absolute branching fractions of the decays D0→K−e+νe and D+→K¯0e+νe to be (3.567±0.031stat±0.025syst)% and (8.68±0.14stat±0.16syst)%, respectively. Starting with the process e+e−→DD¯, a new reconstruction method is employed to select events that contain candidates for both D→K¯e+νe and D¯→Ke−ν¯e decays. The branching fractions reported in this work are consistent within uncertainties with previous BESIII measurements that selected events containing D→K¯e+νe and hadronic D¯ decays. Combining our results with the lifetimes of the D0 and D+ mesons and the previous BESIII measurements leads to a ratio of the two decay partial widths of Γ¯D0→K−e+νeΓ¯D+→K¯0e+νe=1.039±0.021. This ratio supports isospin symmetry in the D0→K−e+νe and D+→K¯0e+νe decays within 1.9σ.
We measure the inclusive semielectronic decay branching fraction of the D+s meson. A double-tag technique is applied to e+e− annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range 4.178−4.230 GeV. We select positrons from D+s→Xe+νe 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 B(D+s→Xe+νe)=(6.30±0.13(stat.)±0.10(syst.))%, 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, Γ(D+s→Xe+νe)Γ(D0→Xe+νe)=0.790±0.016(stat.)±0.020(syst.). Our results are consistent with and more precise than previous measurements.
Using 10.1 × 109 J/ψ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy √s = 3.097 GeV and collected with the BESIII detector, we present a search for the rare semi-leptonic decay J/ψ → D−e+νe + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction B(J/ψ → D−e +νe + c.c.) < 7.1 × 10−8 is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.
Using a total of 5.25 fb−1 of e+e− collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the process e+e− → ηψ(2S) with a statistical significance of 4.9 standard deviations. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.
Using a data set of electron-positron collisions corresponding to an integrated luminosity of 2.93 fb−1 taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, a search for the baryon (B) and lepton (L) number violating decays D±→n(n¯)e± is performed. No signal is observed and the upper limits on the branching fractions at the 90% confidence level are set to be 1.43×10−5 for the decays D+(−)→n¯(n)e+(−) with Δ|B−L|=0, and 2.91×10−5 for the decays D+(−)→n(n¯)e+(−) with Δ|B−L|=2 , where Δ|B−L| denotes the change in the difference between baryon and lepton numbers.
Search for the lepton number violating decay Σ⁻ → pe⁻e⁻ and the rare inclusive decay Σ⁻ → Σ⁺X
(2021)
Using a data sample of (1310.6±7.0)×106 𝐽/𝜓 events taken with the BESIII detector at the center-of-mass energy of 3.097 GeV, we search for the first time for the lepton number violating decay Σ−→𝑝𝑒−𝑒− and the rare inclusive decay Σ−→Σ+𝑋, where 𝑋 denotes any possible particle combination. The Σ− candidates are tagged in 𝐽/𝜓→¯Σ(1385)+Σ− decays. No signal candidates are found, and the upper limits on the branching fractions at the 90% confidence level are determined to be ℬ(Σ−→𝑝𝑒−𝑒−)<6.7×10−5 and ℬ(Σ−→Σ+𝑋)<1.2×10−4.
Precision measurements of the semileptonic decays 𝐷+𝑠→𝜂𝑒+𝜈𝑒 and 𝐷+𝑠→𝜂′𝑒+𝜈𝑒 are performed with 7.33 fb−1 of 𝑒+𝑒− collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector. The branching fractions obtained are ℬ(𝐷+𝑠→𝜂𝑒+𝜈𝑒) = (2.255±0.039stat±0.051syst)% and ℬ(𝐷+𝑠→𝜂′𝑒+𝜈𝑒)=(0.810±0.038stat±0.024syst)%. Combining these results with the ℬ(𝐷+→𝜂𝑒+𝜈𝑒) and ℬ(𝐷+→𝜂′𝑒+𝜈𝑒) obtained from previous BESIII measurements, the 𝜂−𝜂′ mixing angle in the quark flavor basis is determined to be 𝜙P=(40.0±2.0stat±0.6syst)°. Moreover, from the fits to the partial decay rates of 𝐷+𝑠→𝜂𝑒+𝜈𝑒 and 𝐷+𝑠→𝜂′𝑒+𝜈𝑒, the products of the hadronic transition form factors 𝑓𝜂(′)+(0) and the modulus of the 𝑐→𝑠 Cabibbo-Kobayashi-Maskawa matrix element |𝑉𝑐𝑠| are determined by using different hadronic transition form factor parametrizations. Based on the two-parameter series expansion, the products 𝑓𝜂+(0)|𝑉𝑐𝑠| = 0.4519±0.0071stat±0.0065syst and 𝑓𝜂′+(0)|𝑉𝑐𝑠| = 0.525±0.024stat±0.009syst are extracted. All results determined in this work supersede those measured in the previous BESIII analyses based on the 3.19 fb−1 subsample of data at 4.178 GeV.
Using 9.0 fb−1 of e+e− collision data collected at center-of-mass energies from 4.178 to 4.278 GeV with the BESIII detector at the BEPCII collider, we perform the first search for the radiative transition χc1(3872)→γψ2(3823). No χc1(3872)→γψ2(3823) signal is observed. The upper limit on the ratio of branching fractions B(χc1(3872)→γψ2(3823),ψ2(3823)→γχc1)/B(χc1(3872)→π+π−J/ψ) is set as 0.075 at the 90\% confidence level. Our result contradicts theoretical predictions under the assumption that the χc1(3872) is the pure charmonium state χc1(2P).
We measure the inclusive semielectronic decay branching fraction of the D+s meson. A double-tag technique is applied to e+e− annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range 4.178–4.230 GeV. We select positrons fromD+s→Xe+νe 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(6.30±0.13(stat.)±0.09(syst.)±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, Γ(D+s→Xe+νe)Γ(D0→Xe+νe)=0.790±0.016(stat.)±0.011(syst.)±0.016(ext.). Our results are consistent with and more precise than previous measurements.
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.
During the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5 fb -1 of e+e− collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process e+e− (γISR/FSR)µ -> +µ-, we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-collection period.
Using data samples with an integrated luminosity of 22.42 fb−1 collected by the BESIII detector operating at the BEPCII storage ring, we measure the cross sections of the $e^{+}e^{-}\rightarrow\etaJ/\psi$ process at center-of-mass energies from 3.808 to 4.951 GeV. Three structures are observed in the line shape of the measured cross sections. A maximum-likelihood fit with ψ(4040), two additional resonances, and a non-resonant component is performed. The mass and width of the first additional state are (4219.7±2.5±4.5)MeV/c2 and (80.7±4.4±1.4)MeV, respectively, consistent with the ψ(4230). For the second state, the mass and width are (4386±13±17)MeV/c2 and (177±32±13)MeV, respectively, consistent with the ψ(4360). The first uncertainties are statistical and the second ones are systematic. The statistical significance of ψ(4040) is 8.0σ and those for ψ(4230) and ψ(4360) are more than 10.0σ.
The Born cross sections of the e+e− → D*+D*− and e+e− → D*+D− processes are measured using e+e− collision data collected with the BESIII experiment at center-of-mass energies from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of 15.7 fb−1. The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states.
Using inclusive decays of the J/ψ, a precise determination of the number of J/ψ events collected with the BESIII detector is performed. For the two data sets taken in 2009 and 2012, the numbers of J/ψ events are recalculated to be (224.0±1.3)×106 and (1088.5±4.4)×106 respectively, which are in good agreement with the previous measurements. For the J/ψ sample taken in 2017--2019, the number of events is determined to be (8774.0±39.4)×106. The total number of J/ψ events collected with the BESIII detector is determined to be (10087±44)×106, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.
The Cabbibo-favored decay Λ+c→Ξ0K+π0 is studied for the first time using 6.1 fb−1 of e+e− collision data at center-of-mass energies between 4.600 and 4.840 GeV, collected with the BESIII detector at the BEPCII collider. With a double-tag method, the branching fraction of the three-body decay Λ+c→Ξ0K+π0 is measured to be (7.79±1.46±0.71)×10−3, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction of the two-body decay Λ+c→Ξ(1530)0K+ is (5.99±1.04±0.29)×10−3, which is consistent with the previous result of (5.02±0.99±0.31)×10−3. In addition, the upper limit on the branching fraction of the doubly Cabbibo-suppressed decay Λ+c→nK+π0 is 7.1×10−4 at the 90% confidence level. The upper limits on the branching fractions of Λ+c→Σ0K+π0 and ΛK+π0 are also determined to be 1.8×10−3 and 2.0×10−3, respectively.
Observation of resonance structures in e⁺e⁻ → π⁺π⁻ψ₂(3823) and mass measurement of ψ₂(3823)
(2022)
Using a data sample corresponding to an integrated luminosity of 11.3 fb−1 collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the 𝑒+𝑒−→𝜋+𝜋−𝜓2(3823) cross section and the branching fraction ℬ[𝜓2(3823)→𝛾𝜒𝑐1]. For the first time, resonance structure is observed in the cross section line shape of 𝑒+𝑒−→𝜋+𝜋−𝜓2(3823) with significances exceeding 5𝜎. A fit to data with two coherent Breit-Wigner resonances modeling the √𝑠-dependent cross section yields 𝑀(𝑅1)=4406.9±17.2±4.5 MeV/𝑐2, Γ(𝑅1)=128.1±37.2±2.3 MeV, and 𝑀(𝑅2)=4647.9±8.6±0.8 MeV/𝑐2, Γ(𝑅2)=33.1±18.6±4.1 MeV. Though weakly disfavored by the data, a single resonance with 𝑀(𝑅)=4417.5±26.2±3.5 MeV/𝑐2, Γ(𝑅)=245±48±13 MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the 𝜓2(3823) state is measured as (3823.12±0.43±0.13) MeV/𝑐2, which is the most precise measurement to date.
Using 448 million ψ(2S) events, the spin-singlet P-wave charmonium state hc(11P1) is studied via the ψ(2S)→π0hc decay followed by the hc→γηc transition. The branching fractions are measured to be BInc(ψ(2S)→π0hc)×BTag(hc→γηc)=(4.22+0.27−0.26±0.19)×10−4 , BInc(ψ(2S)→π0hc)=(7.32±0.34±0.41)×10−4, and BTag(hc→γηc)=(57.66+3.62−3.50±0.58)%, where the uncertainties are statistical and systematic, respectively. The hc(11P1) mass and width are determined to be M=(3525.32±0.06±0.15) MeV/c2 and Γ=(0.78+0.27−0.24±0.12) MeV. Using the center of gravity mass of the three χcJ(13PJ) mesons (M(c.o.g.)), the 1P hyperfine mass splitting is estimated to be Δhyp=M(hc)−M(c.o.g.)=(0.03±0.06±0.15) MeV/c2, which is consistent with the expectation that the 1P hyperfine splitting is zero at the lowest-order.
Using 448 million ψ(2S) events, the spin-singlet P-wave charmonium state hc(11P1) is studied via the ψ(2S)→π0hc decay followed by the hc→γηc transition. The branching fractions are measured to be BInc(ψ(2S)→π0hc)×BTag(hc→γηc)=(4.17+0.27−0.25±0.19)×10−4 , BInc(ψ(2S)→π0hc)=(7.23±0.33±0.38)×10−4, and BTag(hc→γηc)=(57.66+3.62−3.50±0.58)%, where the uncertainties are statistical and systematic, respectively. The hc(11P1) mass and width are determined to be M=(3525.32±0.06±0.15) MeV/c2 and Γ=(0.78+0.27−0.24±0.12) MeV. Using the center of gravity mass of the three χcJ(13PJ) mesons (M(c.o.g.)), the 1P hyperfine mass splitting is estimated to be Δhyp=M(hc)−M(c.o.g.)=(0.03±0.06±0.15) MeV/c2, which is consistent with the expectation that the 1P hyperfine splitting is zero at the lowest-order.
Using 15.6 fb−1 of e+e− collision data collected at twenty-four center-of-mass energies from 4.0 to 4.6 GeV with the BESIII detector, the helicity amplitudes of the process e+e− → π+π−ω are analyzed for the first time. Born cross section measurements of two-body intermediate resonance states with statistical significance greater than 5σ are presented, such as f0(500), f0(980), f2(1270), f0(1370), b1(1235)±, and ρ(1450)±. In addition, evidence of a resonance state in e+e− → π+π−ω production is found. The mass of this state obtained by line shape fitting is about 4.2 GeV/c2, which is consistent with the production of ψ(4160) or Y(4220).
The electromagnetic process is studied with the initial-state-radiation technique using 7.5 fb−1 of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/ using the invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution.
The cross sections of e+e−→K+K−J/ψ at center-of-mass energies from 4.127 to 4.600~GeV are measured based on 15.6 fb−1 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 (4225.3±2.3±21.5) MeV and (72.9±6.1±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 8σ, denoted as Y(4500). Its mass and width are determined to be (4484.7±13.3±24.1) MeV and (111.1±30.1±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 Γ(Y(4230)→e+e−)B(Y(4230)→K+K−J/ψ) is reported.
Using e+e− annihilation data corresponding to an integrated luminosity of 6.32 fb−1 collected at center-of-mass energies between 4.178 GeV and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay D+s→K0SK+π0 and determine the relative branching fractions and phases for intermediate processes. We observe the a0(1710)+, the isovector partner of the f0(1710) and f0(1770) mesons, in its decay to K0SK+ for the first time. In addition, we measure the ratio B(D+s→K¯∗(892)0K+)B(D+s→K¯0K∗(892)+) to be 2.35+0.42−0.23stat.±0.10syst.. Finally, we provide a precision measurement of the absolute branching fraction B(D+s→K0SK+π0)=(1.46±0.06stat.±0.05syst.)%.
Using 448 million ψ(2S) events, the spin-singlet P-wave charmonium state hc(11P1) is studied via the ψ(2S)→π0hc decay followed by the hc→γηc transition. The branching fractions are measured to be BInc(ψ(2S)→π0hc)×BTag(hc→γηc)=(4.22+0.27−0.26±0.19)×10−4 , BInc(ψ(2S)→π0hc)=(7.32±0.34±0.41)×10−4, and BTag(hc→γηc)=(57.66+3.62−3.50±0.58)%, where the uncertainties are statistical and systematic, respectively. The hc(11P1) mass and width are determined to be M=(3525.32±0.06±0.15) MeV/c2 and Γ=(0.78+0.27−0.24±0.12) MeV. Using the center of gravity mass of the three χcJ(13PJ) mesons (M(c.o.g.)), the 1P hyperfine mass splitting is estimated to be Δhyp=M(hc)−M(c.o.g.)=(0.03±0.06±0.15) MeV/c2, which is consistent with the expectation that the 1P hyperfine splitting is zero at the lowest-order.
During the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5~fb−1 of e+e− collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process e+e−→(γISR/FSR)μ+μ−, we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-taking period.
Based on e+e− collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis isperformed for the process e+e− → K0SK0Lπ0. The results allow the Born cross sections of the process e+e− → K0SK0Lπ0, as well as its subprocesses e+e− → K∗(892)0K¯ 0 and K∗2(1430)0K¯ 0 to be measured. The Born cross sections for e+e− → K0SK0 Lπ 0 are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process e+e − → K∗(892)0K¯ 0 is consistent with a vector meson state around 2.2 GeV with a signifcance of 3.2σ. A Breit-Wigner ft determines its mass as MY = (2164.7 ± 9.1 ± 3.1) MeV/c2 and its width as ΓY = (32.4 ± 21.0 ± 1.8) MeV.
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.
During the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5~fb−1 of e+e− collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process e+e−→(γISR/FSR)μ+μ−, we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-taking period.
The integrated luminosities of data samples collected in the BESIII experiment in 2016–2017 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 2010–2014 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.
Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay D+ → π+π0π0 and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of D+ → π+π0π0 is measured to be (2.888 ± 0.058stat. ± 0.069syst.)%. The dominant intermediate processes are D+ → a1(1260)+(→ ρ+π0) and D+ → *0ρ+, with branching fractions of (8.66 ± 1.04stat. ± 1.39syst.) × 10−3 and (9.70 ± 0.81stat. ± 0.53syst.) × 10−3, respectively.
Using e+e− annihilation data corresponding to a total integrated luminosity of 6.32 fb−1 collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay D+s→K−K+π+π+π− and determine the relative fractions and phases of different intermediate processes. Absolute branching fraction of D+s→K−K+π+π+π− decay is measured to be (6.60±0.47stat.±0.35syst.)×10−3. The dominant intermediate process is D+s→a1(1260)+ϕ,ϕ→K−K+,a1(1260)+→ρπ+,ρ→π+π−, with a branching fraction of (5.16±0.41stat.±0.27syst.)×10−3.
Using a data set of electron-positron collisions corresponding to an integrated luminosity of 2.93 fb−1 taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, a search for the baryon (B) and lepton (L) number violating decays D±→n(n¯)e± is performed. No signal is observed and the upper limits on the branching fractions at the 90% confidence level are set to be 1.43×10−5 for the decays D+(−)→n¯(n)e+(−) with Δ|B−L|=0, and 2.91×10−5 for the decays D+(−)→n(n¯)e+(−) with Δ|B−L|=2 , where Δ|B−L| denotes the change in the difference between baryon and lepton numbers.
Using a sample of 4.3×105 η′→ηπ0π0 events selected from the ten billion J/ψ event dataset collected with the BESIII detector, we study the decay η′→ηπ0π0 within the framework of nonrelativistic effective field theory. Evidence for a structure at π+π− mass threshold is observed in the invariant mass spectrum of π0π0 with a statistical significance of around 3.5σ, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the ππ scattering length combination a0−a2 is determined to be 0.226±0.060stat±0.013syst, which is in good agreement with theoretical calculation of 0.2644±0.0051.
Using a sample of 4.3×105 η′→ηπ0π0 events selected from the ten billion J/ψ event dataset collected with the BESIII detector, we study the decay η′→ηπ0π0 within the framework of nonrelativistic effective field theory. Evidence for a structure at π+π− mass threshold is observed in the invariant mass spectrum of π0π0 with a statistical significance of around 3.5σ, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the ππ scattering length combination a0−a2 is determined to be 0.226±0.060stat±0.013syst, which is in good agreement with theoretical calculation of 0.2644±0.0051.