Refine
Year of publication
Language
- English (430)
Has Fulltext
- yes (430)
Is part of the Bibliography
- no (430)
Keywords
- BESIII (19)
- e +-e − Experiments (15)
- Branching fraction (11)
- Particle and Resonance Production (8)
- Charm Physics (6)
- Spectroscopy (6)
- Hadronic decays (5)
- Quarkonium (5)
- Branching fractions (4)
- Charmonium (4)
- Exotics (4)
- Heavy-ion collisions (4)
- Lepton colliders (4)
- Charmed mesons (3)
- Diffraction (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)
- Collectivity (2)
- Correlation (2)
- Cross section (2)
- Elastic scattering (2)
- Electroweak Interaction (2)
- Flavour Physics (2)
- Hadronic cross section (2)
- Leptonic, semileptonic & radiative decays (2)
- Muon anomaly (2)
- Particle decays (2)
- Pion form factor (2)
- QCD (2)
- Radiative decay (2)
- Shear viscosity (2)
- decays (2)
- 900 GeV (1)
- ALICE (1)
- Angular distribution (1)
- Annihilation (1)
- B-slope (1)
- BESIII detector (1)
- Beam energy scan (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)
- Coalescence (1)
- Cold nuclear matter effects (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)
- D⁰ meson (1)
- Effective form factor (1)
- Electromagnetic amplitude (1)
- Electromagnetic form factor (1)
- Electromagnetic form factors (1)
- Elliptic flow (1)
- Experimental nuclear physics (1)
- Experimental particle physics (1)
- FOS: Physical sciences (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Form factors (1)
- Forward physics (1)
- Groomed jet radius (1)
- Hadron-Hadron scattering (experiments) (1)
- Hadrons (1)
- Heavy Ion Experiments (1)
- Heavy Quark Production (1)
- Heavy-Ion Collision (1)
- Heavy-flavor decay electron (1)
- Helicity amplitude analysis (1)
- High Energy Physics - Experiment (hep-ex) (1)
- Higher moments (1)
- Hyperons (1)
- Inclusive branching fraction (1)
- Invisible decays (1)
- J/ψ suppression (1)
- Jet substructure (1)
- K0S (1)
- LHC (1)
- Neutrinos (1)
- PYTHIA (1)
- Particle and resonance production (1)
- Particle phenomena (1)
- Phase (1)
- Polarization (1)
- Proton (1)
- Proton-proton collisions (1)
- Proton–proton collisions (1)
- Quantum chromodynamics (1)
- R value (1)
- RHIC (1)
- Rare decays (1)
- STAR (1)
- Semi-leptonic decays (1)
- SoftDrop (1)
- Splitting function (1)
- Strong amplitude (1)
- Techniques Electromagnetic calorimeters (1)
- Thermal model (1)
- Threshold effect (1)
- Transverse momentum (1)
- Triple quarkonia (1)
- W-exchange (1)
- Y (4260) (1)
- Y states (1)
- branching fractions (1)
- center-of-mass energy (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)
- luminosity (1)
- number of J/ψ events (1)
- tetraquark (1)
- trigger efficiency (1)
- Λ+c baryon (1)
- Λc⁺ (1)
- Σ hyperon (1)
- Υ suppression (1)
- ψ(3686) (1)
Institute
- Physik (336)
- Frankfurt Institute for Advanced Studies (FIAS) (91)
- Medizin (2)
- Informatik (1)
Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, we investigate the semileptonic decays D+→π+π−ℓ+νℓ (ℓ=e and μ). The D+→f0(500)μ+νμ decay is observed for the first time. By analyzing simultaneously the differential decay rates of D+→f0(500)μ+νμ and D+→f0(500)e+νe in different ℓ+νℓ four-momentum transfer intervals, the product of the relevant hadronic form factor ff0+(0) and the magnitude of the c→d Cabibbo-Kobayashi-Maskawa matrix element |Vcd| is determined to be ff0+(0)|Vcd|=0.0787±0.0060stat±0.0033syst for the first time. With the input of |Vcd| from the global fit in the standard model, we determine ff0+(0)=0.350±0.027stat±0.015syst. The absolute branching fractions of D+→f0(500)(π+π−)μ+νμ and D+→ρ0(π+π−)μ+νμ are determined as (0.72±0.13stat±0.10syst)×10−3 and (1.64±0.13stat±0.11syst)×10−3. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios BD+→ρ0μ+νμ/BD+→ρ0e+νe = 0.88±0.10 and BD+→f0(500)μ+νμ/BD+→f0(500)e+νe = 1.14±0.28, which are compatible with the standard model expectation.
Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, we investigate the semileptonic decays D+→π+π−ℓ+νℓ (ℓ=e and μ). The D+→f0(500)μ+νμ decay is observed for the first time. By analyzing simultaneously the differential decay rates of D+→f0(500)μ+νμ and D+→f0(500)e+νe in different ℓ+νℓ four-momentum transfer intervals, the product of the relevant hadronic form factor ff0+(0) and the magnitude of the c→d Cabibbo-Kobayashi-Maskawa matrix element |Vcd| is determined to be ff0+(0)|Vcd|=0.0787±0.0060stat±0.0033syst for the first time. With the input of |Vcd| from the global fit in the standard model, we determine ff0+(0)=0.350±0.027stat±0.015syst. The absolute branching fractions of D+→f0(500)(π+π−)μ+νμ and D+→ρ0(π+π−)μ+νμ are determined as (0.72±0.13stat±0.10syst)×10−3 and (1.64±0.13stat±0.11syst)×10−3. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios BD+→ρ0μ+νμ/BD+→ρ0e+νe=0.88±0.10 and BD+→f0(500)μ+νμ/BD+→f0(500)e+νe = 1.14±0.28, which are compatible with the standard model expectation.
By analyzing 𝑒+𝑒− annihilation data with an integrated luminosity of 2.93 fb−1 collected at the center-of-mass energy √𝑠=3.773 GeV with the BESIII detector, we present the first absolute measurements of the branching fractions of twenty Cabibbo-suppressed hadronic 𝐷0(+) decays involving multiple pions. The highest four branching fractions obtained are ℬ(𝐷0→𝜋+𝜋−𝜋0) = (1.343±0.013stat±0.016syst)%, ℬ(𝐷0→𝜋+𝜋−2𝜋0) = (1.002±0.019stat±0.024syst)%, ℬ(𝐷+→2𝜋+𝜋−𝜋0) = (1.165±0.021stat±0.021syst)%, and ℬ(𝐷+→2𝜋+𝜋−2𝜋0) = (1.074±0.040stat±0.030syst)%. The 𝐶𝑃 asymmetries for the six decays with highest signal yields are also determined and found to be compatible with zero.
By analyzing e+e− annihilation data with an integrated luminosity of 2.93 fb−1 collected at the center-of-mass energy s√= 3.773 GeV with the BESIII detector, we present the first absolute measurements of the branching fractions of twenty Cabibbo-suppressed hadronic D0(+) decays involving multiple pions. The largest four branching fractions obtained are B(D0→π+π−π0) = >(1.343±0.013stat±0.016syst)%, B(D0→π+π−2π0) = (0.998±0.019stat±0.024syst)%, B(D+→2π+π−π0)
(1.174±0.021stat±0.021syst)%, and B(D+→2π+π−2π0) = (1.074±0.040stat±0.030syst)%. The CP asymmetries for the six decays with highest event yields are also determined.
Relative fractions and phases of the intermediate decays are determined. With the detection efficiency estimated by the results of the amplitude analysis, the branching fraction of Dþ s → K−Kþπþπ0 decay is measured to be ð5.42 0.10stat 0.17systÞ%.
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.
We report an amplitude analysis and branching fraction measurement of 𝐷+
𝑠→𝐾+𝐾−𝜋+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV. We perform a model-independent partial wave analysis in the low 𝐾+𝐾− mass region to determine the 𝐾+𝐾− S-wave line shape, followed by an amplitude analysis of our very pure high-statistics sample. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be ℬ(𝐷+𝑠→𝐾+𝐾−𝜋+)=(5.47±0.08stat±0.13sys)%.
We report an amplitude analysis and branching fraction measurement of D+s→K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV.
We perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave lineshape, followed by an amplitude analysis of our very pure high-statistics sample.
The amplitude analysis provides an accurate determination of the detection efficiency allowing us to measure the branching fraction B(D+s→K+K−π+)=(5.47±0.08stat±0.13sys)%.
We report an amplitude analysis and branching fraction measurement of D+s→K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV.
We perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave lineshape, followed by an amplitude analysis of our very pure high-statistics sample.
The amplitude analysis provides an accurate determination of the detection efficiency allowing us to measure the branching fraction B(D+s→K+K−π+)=(5.47±0.08stat±0.13sys)%.
We report an amplitude analysis and branching fraction measurement of D+s→K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV.
We perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave lineshape,
followed by an amplitude analysis of our very pure high-statistics sample.
The amplitude analysis provides an accurate determination of the detection efficiency allowing us to measure the branching fraction B(D+s→K+K−π+)=(5.47±0.08stat±0.13sys)%.
We report an amplitude analysis and branching fraction measurement of D+s→K+K−π+ decay using a data sample of 3.19 fb−1 recorded with BESIII detector at a center-of-mass energy of 4.178 GeV.
We perform a model-independent partial wave analysis in the low K+K− mass region to determine the K+K− S-wave lineshape, followed by an amplitude analysis of our very pure high-statistics sample.
The amplitude analysis provides an accurate determination of the detection efficiency allowing us to measure the branching fraction B(D+s→K+K−π+)=(5.47±0.08stat±0.13sys)%.
The singly Cabibbo-suppressed decay D+s → K+π+π−π0 is observed by using a data set corresponding to an integrated luminosity of 6.32 fb−1 recorded by the BESIII detector at the centre-of-mass energies between 4.178 and 4.226 GeV. The first amplitude analysis of D+s → K+π+π−π0 reveals the sub-structures in this decay and determines the fractions and relative phases of different intermediate processes. The dominant intermediate process is D+s → K∗0ρ+, with a fit fraction of (40.5 ± 2.8stat. ± 1.5syst.)%. With the detection efficiency based on our amplitude analysis, the absolute branching fraction forD+s → K+π+π−π0 is measured to be (9.75 ± 0.54stat. ± 0.17syst.) × 10−3.
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 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)%.
By using 6.32 fb−1 of data collected with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we perform an amplitude analysis of the decay D+s ! K0S + 0 and determine the relative fractions and phase differences of different intermediate processes, which include K0S (770)+, K0S (1450)+, K (892)0 +, K (892)+ 0, and K (1410)0 +. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be B(D+s ! K0S + 0) = (5.43 ± 0.30stat ± 0.15syst) × 10−3.
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)%.
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 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.
Using e+e− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy s√=3.773~GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0→π+π−π+π− and D0→π+π−π0π0(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of D0→a1(1260)π, D0→π(1300)π, D0→ρ(770)ρ(770) and D0→2(ππ)S are found in both channels. With the obtained amplitude model, the CP-even fractions of D0→π+π−π+π− and D0→π+π−π0π0(non-η) are determined to be (75.2±1.1stat.±1.5syst.)% and (68.9±1.5stat.±2.4syst.)%, respectively. The branching fractions of D0→π+π−π+π− and D0→π+π−π0π0(non-η) are measured to be (0.688±0.010stat.±0.010syst.)% and (0.951±0.025stat.±0.021syst.)%, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of D0→4π when used to determine the CKM angle γ(ϕ3) via the B−→DK− decay.
Using e+e− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy s√=3.773~GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0→π+π−π+π− and D0→π+π−π0π0(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of D0→a1(1260)π, D0→π(1300)π, D0→ρ(770)ρ(770) and D0→2(ππ)S are found in both channels. With the obtained amplitude model, the CP-even fractions of D0→π+π−π+π− and D0→π+π−π0π0(non-η) are determined to be (75.2±1.1stat.±1.5syst.)% and (68.9±1.5stat.±2.4syst.)%, respectively. The branching fractions of D0→π+π−π+π− and D0→π+π−π0π0(non-η) are measured to be (0.688±0.010stat.±0.010syst.)% and (0.951±0.025stat.±0.021syst.)%, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of D0→4π when used to determine the CKM angle γ(ϕ3) via the B−→DK− decay.
An amplitude analysis of the 𝐾𝑆𝐾𝑆 system produced in radiative 𝐽/𝜓 decays is performed using the (1310.6±7.0)×106 𝐽/𝜓 decays collected by the BESIII detector. Two approaches are presented. A mass-dependent analysis is performed by parametrizing the 𝐾𝑆𝐾𝑆 invariant mass spectrum as a sum of Breit-Wigner line shapes. Additionally, a mass-independent analysis is performed to extract a piecewise function that describes the dynamics of the 𝐾𝑆𝐾𝑆 system while making minimal assumptions about the properties and number of poles in the amplitude. The dominant amplitudes in the mass-dependent analysis include the 𝑓0(1710), 𝑓0(2200), and 𝑓′2(1525). The mass-independent results, which are made available as input for further studies, are consistent with those of the mass-dependent analysis and are useful for a systematic study of hadronic interactions. The branching fraction of radiative 𝐽/𝜓 decays to 𝐾𝑆𝐾𝑆 is measured to be (8.1±0.4)×10−4, where the uncertainty is systematic and the statistical uncertainty is negligible.
The branching fraction of D+→K0Sπ0e+νe is measured for the first time using 7.93 fb−1 of e+e− annihilation data collected at the center-of-mass energy s√=3.773~GeV with the BESIII detector operating at the BEPCII collider, and is determined to be B(D+→K0Sπ0e+νe) = (0.881 ± 0.017stat. ± 0.016syst.)\%. Based on an analysis of the D+→K0Sπ0e+νe decay dynamics, we observe the S-wave and P-wave components with fractions of fS-wave = (6.13 ± 0.27stat. ± 0.30syst.)% and fK¯∗(892)0 = (93.88 ± 0.27stat. ± 0.29syst.)\%, respectively. From these results, we obtain the branching fractions B(D+→(K0Sπ0)S-wave e+νe) = (5.41 ± 0.35stat. ± 0.37syst.)×10−4 and B(D+→K¯∗(892)0e+νe) = (4.97 ± 0.11stat. ± 0.12syst.)\%. In addition, the hadronic form-factor ratios of D+→K¯∗(892)0e+νe at q2=0, assuming a single-pole dominance parameterization, are determined to be rV=V(0)A1(0)=1.43 ± 0.07stat. ± 0.03syst. and r2=A2(0)A1(0)=0.72 ± 0.06stat. ± 0.02syst.
Azimuthal anisotropy measurement of (multi-)strange hadrons in Au+Au collisions at √sNN = 54.4 GeV
(2023)
Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of K0S, ϕ, Λ, Ξ and Ω at mid-rapidity (|y|<1) in Au+Au collisions at sNN−−−√ = 54.4 GeV measured by the STAR detector. The v2 and v3 are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. v3 is found to be more sensitive to the change in the center-of-mass energy than v2. Scaling by constituent quark number is found to hold for v2 within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in v2 and v3 between baryons and anti-baryons are presented, and ratios of v3/v3/22 are studied and motivated by hydrodynamical calculations. The ratio of v2 of ϕ mesons to that of anti-protons (v2(ϕ)/v2(p¯)) shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on anti-proton v2.
We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton distributions, from sNN−−−−√=3−200 GeV Au+Au collisions at RHIC. The net-proton cumulant ratios generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at sNN−−−−√ = 3 GeV. C6/C2 for 0-40\% centrality collisions is increasingly negative with decreasing sNN−−−−√, while it is positive for the lowest sNN−−−−√ studied. These observed negative signs are consistent with QCD calculations (at baryon chemical potential, μB≤ 110 MeV) that include a crossover quark-hadron transition. In addition, for sNN−−−−√≥ 11.5 GeV, the measured proton κn, within uncertainties, does not support the two-component shape of proton distributions that would be expected from a first-order phase transition. Taken in combination, the hyper-order proton number fluctuations suggest that the structure of QCD matter at high baryon density, μB∼750 MeV (sNN−−−−√ = 3 GeV) is starkly different from those at vanishing μB∼20MeV (sNN−−−−√ = 200 GeV and higher).
The linear and mode-coupled contributions to higher-order anisotropic flow are presented for Au+Au collisions at √sN N = 27, 39, 54.4, and 200 GeV and compared to similar measurements for Pb+Pb collisions at the Large Hadron Collider (LHC). The coefficients and the flow harmonics’ correlations, which characterize the linear and mode-coupled response to the lower-order anisotropies, indicate a beam energy dependence consistent with an influence from the specific shear viscosity (η/s). In contrast, the dimensionless coefficients, mode-coupled response coefficients, and normalized symmetric cumulants are approximately beam-energy independent, consistent with a significant role from initialstate effects. These measurements could provide unique supplemental constraints to (i) distinguish between different initial-state models and (ii) delineate the temperature (T ) and baryon chemical potential (μB ) dependence of the specific shear viscosity η s (T ,μB ).
The linear and mode-coupled contributions to higher-order anisotropic flow are presented for Au+Au collisions at sNN−−−√ = 27, 39, 54.4, and 200 GeV and compared to similar measurements for Pb+Pb collisions at the Large Hadron Collider (LHC). The coefficients and the flow harmonics' correlations, which characterize the linear and mode-coupled response to the lower-order anisotropies, indicate a beam energy dependence consistent with an influence from the specific shear viscosity (η/s). In contrast, the dimensionless coefficients, mode-coupled response coefficients, and normalized symmetric cumulants are approximately beam-energy independent, consistent with a significant role from initial-state effects. These measurements could provide unique supplemental constraints to (i) distinguish between different initial-state models and (ii) delineate the temperature (T) and baryon chemical potential (μB) dependence of the specific shear viscosity ηs(T,μB).
We report the first measurements of cumulants, up to 4𝑡ℎ order, of deuteron number distributions and protondeuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair √𝑠NN = 7.7 to 200 GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is observed across all collision energies and centralities, consistent with the expectation from global baryon number conservation. The UrQMD model coupled with a phase-space coalescence mechanism qualitatively reproduces the collision-energy dependence of cumulant ratios and proton-deuteron correlations.
We report the first measurements of cumulants, up to 4th order, of deuteron number distributions and proton-deuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair sNN−−−−√~=~7.7 to 200~GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is observed across all collision energies and centralities, consistent with the expectation from global baryon number conservation. The UrQMD model coupled with a phase-space coalescence mechanism qualitatively reproduces the collision-energy dependence of cumulant ratios and proton-deuteron correlations.
Elliptic flow measurements from two-, four- and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sNN−−−√ = 193 GeV, Cu+Au at sNN−−−√ = 200 GeV and Au+Au spanning the range sNN−−−√ = 11.5 - 200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and Glauber model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.
Elliptic flow measurements from two-, four- and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sNN−−−√= 193 GeV, Cu+Au at sNN−−−√= 200 GeV and Au+Au spanning the range sNN−−−√= 11.5 - 200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and T$\mathrel{\protect\raisebox{-2.1pt}{R}}$ENTo model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.
In Ref. [1] the BESIII collaboration published a cross section measurement of the process e+e− → π+π− in the energy range between 600 and 900 MeV. In this corrigendum, we report a corrected evaluation of the statistical errors in terms of a fully propagated covariance matrix. The correction also yields a reduced statistical uncertainty for the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, which now reads as aππ,LO μ (600 − 900 MeV) = (368.2 ± 1.5stat ± 3.3syst) × 10−10. The central values of the cross section measurement and of aππ,LO μ , as well as the systematic uncertainties remain unchanged.
Using data samples with a total integrated luminosity of 20.1 fb−1 collected by the BESIII detector operating at the BEPCII collider, the cross section of the process 𝑒+𝑒−→𝜋+𝜋−𝜓(3686) is measured at center-of-mass energies between 4.0076 and 4.6984 GeV. The measured cross section is consistent with previous results, and with much improved precision. A fit to the measured energy-dependent cross section, which includes three Breit-Wigner functions and a nonresonant contribution, confirms the existence of the charmonium-like states 𝑌(4220), 𝑌(4390), and 𝑌(4660). This is the first observation of the 𝑌(4660) at the BESIII experiment.
We measure the Born cross sections of the process 𝑒+𝑒−→𝐾+𝐾−𝐾+𝐾− at center-of-mass (c.m.) energies, √𝑠, between 2.100 and 3.080 GeV. The data were collected using the BESIII detector at the BEPCII collider. An enhancement at √𝑠=2.232 GeV is observed, very close to the 𝑒+𝑒−→Λ¯Λ production threshold. A similar enhancement at the same c.m. energy is observed in the 𝑒+𝑒−→𝜙𝐾+𝐾− cross section. The energy dependence of the 𝐾+𝐾−𝐾+𝐾− and 𝜙𝐾+𝐾− cross sections differs significantly from that of 𝑒+𝑒−→𝜙𝜋+𝜋−.
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.
We report a systematic measurement of cumulants, Cn, for net-proton, proton and antiproton multiplicity distributions, and correlation functions, κn, for proton and antiproton multiplicity distributions up to the fourth order in Au+Au collisions at sNN−−−√ = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 and 200 GeV. The Cn and κn are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, y, and transverse momentum, pT. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010 -- 2017) at the BNL Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity (|y|< 0.5) and transverse momentum 0.4 < pT < 2.0 GeV/c, using the STAR detector at RHIC. We observe a non-monotonic energy dependence (sNN−−−√ = 7.7 -- 62.4 GeV) of the net-proton C4/C2 with the significance of 3.1σ for the 0-5\% central Au+Au collisions. This is consistent with the expectations of critical fluctuations in a QCD-inspired model. Thermal and transport model calculations show a monotonic variation with sNN−−−√. For the multiparticle correlation functions, we observe significant negative values for a two-particle correlation function, κ2, of protons and antiprotons, which are mainly due to the effects of baryon number conservation. Furthermore, it is found that the four-particle correlation function, κ4, of protons plays a role in determining the energy dependence of proton C4/C1 below 19.6 GeV, which cannot be understood by the effect of baryon number conservation.
We report a systematic measurement of cumulants, Cn, for net-proton, proton and antiproton, and correlation functions, κn, for proton and antiproton multiplicity distributions up to the fourth order in Au+Au collisions at sNN−−−√ = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 and 200 GeV. The Cn and κn are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, y, and transverse momentum, pT. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010 -- 2017) at the Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity (|y|< 0.5) and transverse momentum 0.4 < pT < 2.0 GeV/c, using the STAR detector at RHIC. We observe a non-monotonic energy dependence (sNN−−−√ = 7.7 -- 62.4 GeV) of the net-proton C4/C2 with the significance of 3.1σ for the 0-5\% central Au+Au collisions. This is consistent with the expectations of critical fluctuations in a QCD-inspired model. Thermal and transport model calculations show a monotonic variation with sNN−−−√. For the multiparticle correlation functions, we observe significant negative values for a two-particle correlation function, κ2, of protons and antiprotons, which are mainly due to the effects of baryon number conservation. Furthermore, it is found that the four-particle correlation function, κ4, of protons plays a role in determining the energy dependence of proton C4/C1 below 19.6 GeV, which cannot be solely understood by the negative values of κ2 for protons.
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.
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.
Quantum-correlated 𝐷¯𝐷 pairs collected by the BESIII experiment at the 𝜓(3770) resonance corresponding to an integrated luminosity of 2.93 fb−1 are used to study the 𝐷0→𝐾0𝑆𝜋+𝜋−𝜋0 decay mode. The 𝐶𝑃-even fraction of 𝐷0→𝐾0𝑆𝜋+𝜋−𝜋0 decays is determined to be 0.235±0.010±0.002, where the first uncertainty is statistical and the second is systematic.
Using a 3.19 fb−1 data sample collected at an 𝑒+𝑒− center-of-mass energy of 𝐸cm=4.178 GeV with the BESIII detector, we measure the branching fraction of the leptonic decay 𝐷+𝑠→𝜇+𝜈𝜇 to be ℬ𝐷+𝑠→𝜇+𝜈𝜇=(5.49±0.16stat±0.15syst)×10−3. Combining our branching fraction with the masses of the 𝐷+𝑠 and 𝜇+ and the lifetime of the 𝐷+𝑠, we determine 𝑓𝐷+𝑠|𝑉𝑐𝑠|=246.2±3.6stat±3.5syst MeV. Using the 𝑐→𝑠 quark mixing matrix element |𝑉𝑐𝑠| determined from a global standard model fit, we evaluate the 𝐷+𝑠 decay constant 𝑓𝐷+𝑠=252.9±3.7stat±3.6syst MeV. Alternatively, using the value of 𝑓𝐷+𝑠 calculated by lattice quantum chromodynamics, we find |𝑉𝑐𝑠|=0.985±0.014stat±0.014syst. These values of ℬ𝐷+𝑠→𝜇+𝜈𝜇, 𝑓𝐷+𝑠|𝑉𝑐𝑠|, 𝑓𝐷+𝑠 and |𝑉𝑐𝑠| are each the most precise results to date.
The STAR collaboration presents jet substructure measurements related to both the momentum fraction and the opening angle within jets in p+p and Au+Au collisions at sNN−−−√=200 GeV. The substructure observables include SoftDrop groomed momentum fraction (zg), groomed jet radius (Rg), and subjet momentum fraction ((zSJ)) and opening angle ((θSJ)). The latter observable is introduced for the first time. Fully corrected subjet measurements are presented for p+p collisions and are compared to leading order Monte Carlo models. The subjet θSJ distributions reflect the jets leading opening angle and are utilized as a proxy for the resolution scale of the medium in Au+Au collisions. We compare data from Au+Au collisions to those from p+p which are embedded in minimum-bias Au+Au events in order to include the effects of detector smearing and the heavy-ion collision underlying event. The subjet observables are shown to be more robust to the background than zg and (Rg).
We observe no significant modifications of the subjet observables within the two highest-energy, back-to-back jets, resulting in a distribution of opening angles and the splittings that are vacuum-like. We also report measurements of the differential di-jet momentum imbalance (AJ) for jets of varying θg. We find no qualitative differences in energy loss signatures for varying angular scales in the range 0.1<θSJ<0.3, leading to the possible interpretation that energy loss in this population of high momentum di-jet pairs, is due to soft medium-induced gluon radiation from a single color-charge as it traverses the medium.
The STAR collaboration presents jet substructure measurements related to both the momentum fraction and the opening angle within jets in \pp and \AuAu collisions at \sqrtsn =200 GeV. The substructure observables include SoftDrop groomed momentum fraction (\zg), groomed jet radius (\rg), and subjet momentum fraction (\zsj) and opening angle (\tsj). The latter observable is introduced for the first time. Fully corrected subjet measurements are presented for \pp collisions and are compared to leading order Monte Carlo models. The subjet \tsj~distributions reflect the jets leading opening angle and are utilized as a proxy for the resolution scale of the medium in \AuAu collisions. We compare data from \AuAu collisions to those from \pp which are embedded in minimum-bias \AuAu events in order to include the effects of detector smearing and the heavy-ion collision underlying event. The subjet observables are shown to be more robust to the background than \zg~and \rg.
We observe no significant modifications of the subjet observables within the two highest-energy, back-to-back jets, resulting in a distribution of opening angles and the splittings that are vacuum-like. We also report measurements of the differential di-jet momentum imbalance (AJ) for jets of varying \tsj. We find no qualitative differences in energy loss signatures for varying angular scales in the range 0.1< \tsj <0.3, leading to the possible interpretation that energy loss in this population of high momentum di-jet pairs, is due to soft medium-induced gluon radiation from a single color-charge as it traverses the medium.
We report a measurement of the observed cross sections of e+ e− → J/ψX based on 3.21 fb − 1 of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686) → J/ψX) = (64.4 ± 0.6 ± 1.6)% and B(ψ(3770) → J/ψX) = (0.5 ± 0.2 ± 0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ (3686) → J/ψX and ψ(3770) → J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→ J/ψX. Under this assumption, we extracted the R (3760) mass M R (3760 ) = 3766.2 ± 3.8 ± 0.4 MeV/c2, total width Γ tot R ( 3760 ) = 22.2 ± 5.9 ± 1.4 MeV, and product of leptonic width and decay branching fraction
ΓeeR(3760) B[R(3760) → J/ψX] = (79.4 ± 85.5 ± 11.7) eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.
We report on the measurements of directed flow v1 and elliptic flow v2 for hadrons (π±, K ±, K0 S , p, φ, Λ and ) from Au+Au collisions at √sN N = 3 GeV and v2 for (π±, K ±, p and p) at 27 and 54.4 GeV with the STAR experiment. While at the two higher energy midcentral collisions the numberof-constituent-quark (NCQ) scaling holds, at 3 GeV the v2 at midrapidity is negative for all hadrons and the NCQ scaling is absent. In addition, the v1 slopes at midrapidity for almost all observed hadrons are found to be positive, implying dominant repulsive baryonic interactions. The features of negative v2 and positive v1 slope at 3 GeV can be reproduced with a baryonic mean-field in transport model calculations. These results imply that the medium in such collisions is likely characterized by baryonic interactions.
Elliptic flow of heavy-flavor decay electrons in Au+Au collisions at √sNN = 27 and 54.4 GeV at RHIC
(2023)
We report on new measurements of elliptic flow (v2) of electrons from heavy-flavor hadron decays at mid-rapidity (|y|<0.8) in Au+Au collisions at sNN−−−√ = 27 and 54.4 GeV from the STAR experiment. Heavy-flavor decay electrons (eHF) in Au+Au collisions at sNN−−−√ = 54.4 GeV exhibit a non-zero v2 in the transverse momentum (pT) region of pT< 2 GeV/c with the magnitude comparable to that at sNN−−−√=200 GeV. The measured eHF v2 at 54.4 GeV is also consistent with the expectation of their parent charm hadron v2 following number-of-constituent-quark scaling as other light and strange flavor hadrons at this energy. These suggest that charm quarks gain significant collectivity through the evolution of the QCD medium and may reach local thermal equilibrium in Au+Au collisions at sNN−−−√=54.4 GeV. The measured eHF v2 in Au+Au collisions at sNN−−−√= 27 GeV is consistent with zero within large uncertainties. The energy dependence of v2 for different flavor particles (π,ϕ,D0/eHF) shows an indication of quark mass hierarchy in reaching thermalization in high-energy nuclear collisions.
Elliptic flow of heavy-flavor decay electrons in Au+Au collisions at √sNN = 27 and 54.4 GeV at RHIC
(2023)
We report on new measurements of elliptic flow (v2) of electrons from heavy-flavor hadron decays at mid-rapidity (|y|<0.8) in Au+Au collisions at sNN−−−√ = 27 and 54.4 GeV from the STAR experiment. Heavy-flavor decay electrons (eHF) in Au+Au collisions at sNN−−−√ = 54.4 GeV exhibit a non-zero v2 in the transverse momentum (pT) region of pT< 2 GeV/c with the magnitude comparable to that at sNN−−−√=200 GeV. The measured eHF v2 at 54.4 GeV is also consistent with the expectation of their parent charm hadron v2 following number-of-constituent-quark scaling as other light and strange flavor hadrons at this energy. These suggest that charm quarks gain significant collectivity through the evolution of the QCD medium and may reach local thermal equilibrium in Au+Au collisions at sNN−−−√=54.4 GeV. The measured eHF v2 in Au+Au collisions at sNN−−−√= 27 GeV is consistent with zero within large uncertainties. The energy dependence of v2 for different flavor particles (π,ϕ,D0/eHF) shows an indication of quark mass hierarchy in reaching thermalization in high-energy nuclear collisions.