37059521
Design and implementation of DAQ readout system for the Daya Bay Reactor Neutrino Experiment
The Daya Bay Reactor Neutrino Experiment will consist of seventeen separate detector subsystems distributed in three underground experimental halls. There will be eight PMT based anti-neutrino detectors (ADs), six water-Cherenkov detectors, and three RPC detector subsystems. Each detector will be read out using an independent VME crate. The data acquisition (DAQ) readout system (ROS) reads data fragments from electronics and trigger modules then concatenates them into an event in each crate. A detailed design and implementation of the DAQ readout system for the Daya Bay Reactor Neutrino Experiment will be presented.
116994417
Measurement of $\eta^\prime\rightarrow \pi^+\pi^- e^+e^-$ and $\eta^\prime\rightarrow \pi^+\pi^-\mu^+\mu^-$
Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be \BR(\eta' to pi+pi-e+e-) = (2.11\pm0.12 (stat.)\pm0.15 (syst.))\times10^{-3}, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No \eta' signal is found in the pi+ pi- mu+ mu- mass spectrum, and the upper limit is determined to be \BR(\eta' to pi+ pi- mu+ mu-)<2.9\times10^{-5} at the 90% confidence level.
123325671
BESIII track fitting algorithm
A track fitting algorithm based on the Kalman filter method has been developed for BESⅢ of BEPCⅡ. The effects of multiple scattering and energy loss when the charged particles go through the detector, non-uniformity of magnetic field (NUMF) and wire sag, etc., have been carefully handled. This algor...
12149444
Observation of a Near-Threshold Enhancement in the p-anti-p Mass Spectrum from Radiative J/psi --> gamma-p-anti-p Decays
We observe a narrow enhancement near 2m{sub p} in the invariant mass spectrum of p{bar p} pairs from radiative J/{psi} {yields} {gamma}p{bar p} decays. No similar structure is seen in J/{psi} {yields} {pi}{sup 0} p{bar p} decays. The results are based on an analysis of a 58 million event sample of J/{psi} decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m{sup p} at M = 1859{sub -10}{sup +3} (stat){sub -25}{sup +5} (sys) MeV/c{sup 2} and the total width is {Lambda} < 30 MeV/c{sup 2} at the 90 percent confidence level. These mass and width values are not consistent with the properties of any known particle.
36972437
The architecture of BESIII offline database
This paper presents the BESIII Offline Database for use in the current BESIII experiment at IHEP. The database can be used for the purpose of offline and physical analysis. It manages the history status data of detectors, electronics, slow control subsystem, and online subsystem. These are the data necessary for the online DQM monitor, reconstruction, calibration and data analysis. BESIII offline database also be used to manage calibration data, DQM data and Monte Carlo data. These are also the data necessary for the data analysis. The BESIII database also provide user with web services to make it possible to monitor the status of detectors, slow control subsystem, and online subsystem locally or remotely. The database engine is MySQL server. The database technology route and the database services for the distributed application environment are also presented in this paper.
119274043
Partial wave analysis of $J/\psi \to \gamma \eta \eta$
Based on a sample of $2.25\times 10^{8}$ $J/\psi$ events collected with the BESIII detector at BEPCII, a full partial wave analysis on $J/\psi\to\gamma\eta\eta$ was performed using the relativistic covariant tensor amplitude method. The results show that the dominant $0^{++}$ and $2^{++}$ components are from the $f_0(1710)$, $f_0(2100)$, $f_0(1500)$, $f_2'(1525)$, $f_2(1810)$ and $f_2(2340)$. The resonance parameters and branching fractions are also presented.
118967353
Exotic in Leptonic Machines
Selected topics of exotics in leptonic machines are presented, including recent discovery of abnormal structures around the ppbar threshold and new information of the XYZ (charmonium-like) states.
120189082
RECENT CHARMONIUM RESULTS AT BES-III
Recent results on Charmonium spectrum and decays at Beijing Spectrometers III (BES-III) experiment will be presented. This report includes the following topics: 1, first measurement of the transition rates of ψ′ → π0hc and hc → γηc, and improved measurement of the mass and width of the hc; 2, observations of χcJ → VV, with VV being ɸɸ, ωω and ωɸ, χcJ → ωɸ as well as χc1 → ɸɸ and ωω are first observations; 3, improved measurement of the branching fractions of χcJ decay into neutral pseudo-scalar pairs, including χc0,2 → π0π0 and χc0,2 →ηη. All these measurements are based on the world largest ψ′ data sample collected with the BES-III detector at the Beijing Electron Positron Collider II (BEPC-II).
120311240
Observation of $J/\psi \rightarrow p\bar{p}a_{0}(980)$ at BESIII
Using $2.25\times10^{8}$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process $J/\psi\rightarrow p\bar{p}a_{0}(980)$, $a_{0}(980)\rightarrow \pi^{0}\eta$ with a significance of $6.5\sigma$ ($3.2\sigma$ including systematic uncertainties). The product branching fraction of $J/\psi\rightarrow p\bar{p}a_{0}(980)\rightarrow p\bar{p}\pi^{0}\eta$ is measured to be $(6.8\pm1.2\pm1.3)\times 10^{-5}$, where the first error is statistical and the second is systematic. This measurement provides information on the $a_{0}$ production near threshold coupling to $p\bar{p}$ and improves the understanding of the dynamics of $J/\psi$ decays to four body processes.