The four decay modes D0→ϕπ0, D0→ϕη, D+→ϕπ+, and D+→ϕK+ are studied by using a data sample taken at the centre-of-mass energy s=3.773 GeV with the BESIII detector, corresponding to an integrated ...luminosity of 2.93 fb−1. The branching fractions of the first three decay modes are measured to be B(D0→ϕπ0)=(1.168±0.028±0.028)×10−3, B(D0→ϕη)=(1.81±0.46±0.06)×10−4, and B(D+→ϕπ+)=(5.70±0.05±0.13)×10−3, respectively, where the first uncertainties are statistical and the second are systematic. In addition, the upper limit of the branching fraction for D+→ϕK+ is given to be 2.1×10−5 at the 90% confidence level. The ratio of B(D0→ϕπ0) to B(D+→ϕπ+) is calculated to be (20.49±0.50±0.45)%, which is consistent with the theoretical prediction based on isospin symmetry between these two decay modes.
Observation of J/ψ→γηπ0 Ablikim, M
Physical review. D,
10/2016, Letnik:
94, Številka:
7
Journal Article
Recenzirano
Odprti dostop
We present the first study of the process J/ψ→γηπ0 using (223.7±1.4)×106 J/ψ events accumulated with the BESIII detector at the BEPCII facility. The branching fraction for J/ψ→γηπ0 is measured to be ...B(J/ψ→γηπ0)=(2.14±0.18(stat)±0.25(syst))×10−5. With a Bayesian approach, the upper limits of the branching fractions B(J/ψ→γa0(980),a0(980)→ηπ0) and B(J/ψ→γa2(1320),a2(1320)→ηπ0) are determined to be 2.5×10−6 and 6.6×10−6 at the 95% confidence level, respectively. All of these measurements are given for the first time.
The decays ψ2(3823) → γχc0,1,2, π+ π– J/ψ, π0π0 J/ψ, ηJ/ψ, and π0J/ψ are searched for using the reaction e+e– → π+π– ψ2(3823) in a 19 fb–1 data sample collected at center-of-mass energies between 4.1 ...and 4.7 GeV with the BESIII detector. The process ψ2(3823) → γχc1 is observed in a 9 fb–1 data sample in the center-of-mass energy range 4.3–4.7 GeV, which confirms a previous observation but with a higher significance of 11.8σ, and evidence for ψ2(3823) → γχc2 is found with a significance of 3.2σ for the first time. The branching-fraction ratio $\frac{B(ψ_{2}(3823)→γχ_{c2})}{B(ψ_{2}(3823)→γχ_{c1})}$ is determined. No significant ψ2(3823) signals are observed for any of the other decay channels. Upper limits of branching-fraction ratios for ψ2(3823) → π+π– J/ψ, π0π0 J/ψ, η J/ψ, π0 J/ψ, γχc0 relative to ψ2(3823) → γχc1 are reported. The process e+e– → π0π0 ψ2(3823) is also searched for, and we find evidence for the process with a significance of 4.3σ. The average cross-section ratio $\frac{σ(e^{+}e^{–} → π^{0}π^{0} ψ_{2}(3823))} {σ(e^{+}e^{–} → π^{+}π^{–} ψ_{2}(3823))}$ is also determined.
Using 6.32 fb–1 of electron-positron collision data recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we present the first search for the decay $D^{+}_{s}$ → ...a0(980)0e+νe, a0(980)0 → π0η, which could proceed via a0(980) – f0(980) mixing. No significant signal is observed. An upper limit of 1.2 × 10–4 at the 90% confidence level is set on the product of the branching fractions of $D^{+}_{s}$ → a0(980)0e+νe and a0(980)0 → π0η decays.
We report on a comparison of two possible $Λ^{+}_{c}$ spin hypotheses, J = $\frac{1}{2}$ and $\frac{3}{2}$, via the process e+e– → $Λ^{+}_{c}\bar{Λ}^{-}_{c}$, using the angular distributions of ...$Λ^{+}_{c}$ decays into $pK^{0}_{S}$, Λπ+, Σ0π+, and Σ+ π0. The data were recorded at √s = 4.6 GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb–1. The $Λ^{+}_{c}$ spin is determined to be $J = \frac{1}{2}$, with this value favored over the $\frac{3}{2}$ hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
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