No Arabic abstract
An amplitude analysis of the $K_{S}K_{S}$ system produced in radiative $J/psi$ decays is performed using the $(1310.6pm7.0)times10^{6}$ $J/psi$ decays collected by the BESIII detector. Two approaches are presented. A mass-dependent analysis is performed by parameterizing the $K_{S}K_{S}$ 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 $K_{S}K_{S}$ 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 $f_{0}(1710)$, $f_{0}(2200)$, and $f_{2}^prime(1525)$. 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 $J/psi$ decays to $K_{S}K_{S}$ is measured to be $(8.1 pm 0.4) times 10^{-4}$, where the uncertainty is systematic and the statistical uncertainty is negligible.
An amplitude analysis of the $pi^{0}pi^{0}$ system produced in radiative $J/psi$ decays is presented. In particular, a piecewise function that describes the dynamics of the $pi^{0}pi^{0}$ system is determined as a function of $M_{pi^{0}pi^{0}}$ from an analysis of the $(1.311pm0.011)times10^{9}$ $J/psi$ decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the $pi^0pi^0$ system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of $J/psi to gamma pi^{0}pi^{0}$ is determined to be $(1.15pm0.05)times10^{-3}$, where the uncertainty is systematic only and the statistical uncertainty is negligible.
Using an $e^{+}e^{-}$ annihilation data sample corresponding to an integrated luminosity of $3.19~mathrm{fb}^{-1}$ and collected at a center-of-mass energy $sqrt{s} = 4.178~mathrm{GeV}$ with the BESIII detector, we measure the absolute branching fractions $mathcal{B}(D_{s}^{+} rightarrow K_{S}^{0}K^{+}) = (1.425pm0.038_{rm stat.}pm0.031_{rm syst.})%$ and $mathcal{B}(D_{s}^{+} rightarrow K_{L}^{0}K^{+}) =(1.485pm0.039_{rm stat.}pm0.046_{rm syst.})%$. The branching fraction of $D_{s}^{+} rightarrow K_{S}^{0}K^{+}$ is compatible with the world average and that of $D_{s}^{+} rightarrow K_{L}^{0}K^{+}$ is measured for the first time. We present the first measurement of the $K_{S}^{0}$-$K_{L}^{0}$ asymmetry in the decays $D_{s}^{+} rightarrow K_{S,L}^{0}K^{+}$, and $R(D_{s}^{+} rightarrow K_{S,L}^{0}K^{+})=frac{mathcal{B}(D_{s}^{+} rightarrow K_{S}^{0}K^{+}) -mathcal{B}(D_{s}^{+} rightarrow K_{L}^{0}K^{+})}{mathcal{B}(D_{s}^{+} rightarrow K_{S}^{0}K^{+}) +mathcal{B}(D_{s}^{+} rightarrow K_{L}^{0}K^{+})}= (-2.1pm1.9_{rm stat.}pm1.6_{rm syst.})%$. In addition, we measure the direct $CP$ asymmetries $A_{rm CP}(D_{s}^{pm} rightarrow K_{S}^{0}K^{pm}) = (0.6pm2.8_{rm stat.}pm0.6_{rm syst.})%$ and $A_{rm CP}(D_{s}^{pm} rightarrow K_{L}^{0}K^{pm}) = (-1.1pm2.6_{rm stat.}pm0.6_{rm syst.})%$.
The decay $D^{+} rightarrow K_{S}^{0} pi^{+} pi^{+} pi^{-}$ is studied with an amplitude analysis using a data set of 2.93${mbox{,fb}^{-1}}$ of $e^+e^+$ collisions at the $psi(3770)$ peak accumulated by the BESIII detector. Intermediate states and non-resonant components, and their relative fractions and phases have been determined. The significant amplitudes, which contribute to the model that best fits the data, are composed of five quasi-two-body decays $ K_{S}^{0} a_{1}(1260)^{+}$, $ bar{K}_{1}(1270)^{0} pi^{+}$ $ bar{K}_{1}(1400)^{0} pi^{+}$, $ bar{K}_{1}(1650)^{0} pi^{+}$, and $ bar{K}(1460)^{0} pi^{+}$, a three-body decays $K_{S}^{0}pi^{+}rho^{0}$, as well as a non-resonant component $ K_{S}^{0}pi^{+}pi^{+}pi^{-}$. The dominant amplitude is $ K_{S}^{0} a_{1}(1260)^{+}$, with a fit fraction of $(40.3pm2.1pm2.9)%$, where the first and second uncertainties are statistical and systematic, respectively.
Decays of the form $B^{0}_{(s)}rightarrow J/psi K_{{rm S}}^{0} h^+ h^{left(primeright) -}$ ($h^{(prime)} = K, pi$) are searched for in proton-proton collision data corresponding to an integrated luminosity of $1.0 , {rm fb}^{-1}$ recorded with the LHCb detector. The first observation of the $B^{0}_{s}rightarrow J/psi K_{{rm S}}^{0} K^{pm} pi^{mp}$ decay is reported, with significance in excess of 10 standard deviations. The $B^{0}rightarrow J/psi K_{{rm S}}^{0} K^{+} K^{-}$ decay is also observed for the first time. The branching fraction of $B^{0}rightarrow J/psi K_{{rm S}}^{0} pi^{+} pi^{-}$ is determined, to significantly better precision than previous measurements, using $B^0 rightarrow J/psi K_{{rm S}}^{0}$ as a normalisation channel. Branching fractions and upper limits of the other $B^{0}_{(s)}rightarrow J/psi K_{{rm S}}^{0} h^+ h^{left(primeright) -}$ modes are determined relative to that of the $B^{0}rightarrow J/psi K_{{rm S}}^{0} pi^{+} pi^{-}$ decay.
The first measurement of decay-time-dependent CP asymmetries in the decay $B_s^0rightarrow J/psi K_{rm S}^0$ and an updated measurement of the ratio of branching fractions $mathcal{B}(B_s^0rightarrow J/psi K_{rm S}^0)/mathcal{B}(B_d^0rightarrow J/psi K_{rm S}^0)$} are presented. The results are obtained using data corresponding to an integrated luminosity of 3.0 fb$^{-1}$ of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The results on the CP asymmetries are $A_{DeltaGamma}(B_s^0rightarrow J/psi K_{rm S}^0) = 0.49_{-0.65}^{+0.77}(stat) pm 0.06(syst)$, $C_{rm dir}(B_s^0rightarrow J/psi K_{rm S}^0) = -0.28 pm 0.41(stat) pm 0.08(syst)$ and $S_{rm mix}(B_s^0rightarrow J/psi K_{rm S}^0) = -0.08 pm 0.40(stat) pm 0.08(syst)$. The ratio $mathcal{B}(B_s^0rightarrow J/psi K_{rm S}^0)/mathcal{B}(B_d^0rightarrow J/psi K_{rm S}^0)$ is measured to be $0.0431 pm 0.0017(stat) pm 0.0012(syst) pm 0.0025(f_s/f_d)$, where the last uncertainty is due to the knowledge of the $B_s^0$ and $B_d^0$ production fractions.