Based on the naive quark model, we calculate angular distributions for heavy quarkonium decays into pN＊ （1440）, decuplet baryon pairs, and octet-decuplet baryon pairs. The general formulae of angular distributions ...Based on the naive quark model, we calculate angular distributions for heavy quarkonium decays into pN＊ （1440）, decuplet baryon pairs, and octet-decuplet baryon pairs. The general formulae of angular distributions are given explicitly. Quark mass effects on the violation of the helicity conservation and the prospect to look for them in J/ψ hadronic decays are discussed.展开更多
We describe the algorithm to reconstruct the charged tracks for BESⅢ main drift chamber at BEPCⅡ, including the track finding and fitting. With a new method of the Track Segment Finder （TSF）, the results of presen...We describe the algorithm to reconstruct the charged tracks for BESⅢ main drift chamber at BEPCⅡ, including the track finding and fitting. With a new method of the Track Segment Finder （TSF）, the results of present study indicate that the algorithm can reconstruct the charged tracks over a wide range of momentum with high efficiency, while improving the robustness against the background noise in the drift chamber. The overall performances, including spatial resolution, momentum resolution and secondary vertices reconstruction efficiency, etc. satisfy the requirements of BESⅢ experiment.展开更多
The calibration algorithm for RPC-based muon detector at BESIII has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer...The calibration algorithm for RPC-based muon detector at BESIII has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer, module and strip levels have been calibrated with cosmic ray data. The calibration constants are available for simulation and reconstruction tuning. The results of Monte Carlo and data are also compared to check the validation and reliability of the algorithm.展开更多
The principle of the method for the BESⅢ event start time determination and the code construction are described. The investigation of influence of the noise, the method of rejecting noise and the performance checking...The principle of the method for the BESⅢ event start time determination and the code construction are described. The investigation of influence of the noise, the method of rejecting noise and the performance checking by the Monte Carlo physics data sample are also presented. The preliminary results got from the Monte Carlo simulation are presented, the reconstruction efficiency of J/ψ → anything events at noise level 0 - 60% can achieve above 99%, and the error rate is below 1%.展开更多
We established a method on measuring the D^0-D^0 mixing parameter y for BESIII experiment atthe BEPC II e^＋e^- collider. In this method, the doubly tagged 4（3770） D^0-D^0 events, with one D decaysto CP-eigenstates ...We established a method on measuring the D^0-D^0 mixing parameter y for BESIII experiment atthe BEPC II e^＋e^- collider. In this method, the doubly tagged 4（3770） D^0-D^0 events, with one D decaysto CP-eigenstates and the other D decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/π separation, a likelihood approach, which combines the dE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of y to be 0.007 based on a 20 fb^-1 fully simulated MC sample.展开更多
The results of a study of event tagging strategies for elementary physics processes in the T-charm region are presented. The algorithm for online event filtering is optimized by adopting the information provided by di...The results of a study of event tagging strategies for elementary physics processes in the T-charm region are presented. The algorithm for online event filtering is optimized by adopting the information provided by different sub-detectors according to their strengths and capacities. The algorithm is tested with various generated physics and background events. The results indicate that the algorithm satisfies the requirements of BESⅢ physics analysis and its DAQ system.展开更多
Software alignment is quite important for a tracking detector to reach its ultimate position accuracy and momentum resolution. We developed a new alignment algorithm for the BESⅢ Main Drift Chamber using the Kalman F...Software alignment is quite important for a tracking detector to reach its ultimate position accuracy and momentum resolution. We developed a new alignment algorithm for the BESⅢ Main Drift Chamber using the Kalman Filter method. Two different types of data which are helix tracks and straight tracks are used to test this algorithm, and the results show that the design and implementation is successful.展开更多
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...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 algorithm works well and the performance satisfies the physical requirements tested by the simulation data.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10491303 and 10521003, the Knowledge Innovation Project of Chinese Academy of Sciences under Contract No U-612 （IHEP）.
文摘Based on the naive quark model, we calculate angular distributions for heavy quarkonium decays into pN＊ （1440）, decuplet baryon pairs, and octet-decuplet baryon pairs. The general formulae of angular distributions are given explicitly. Quark mass effects on the violation of the helicity conservation and the prospect to look for them in J/ψ hadronic decays are discussed.
基金Supported by CAS Knowledge Innovation Project(U-602,U-34)National Natural Science Foundation of China(10491300,10491303,10605030)100 Talents Program of CAS(U-25,U-54)
文摘We describe the algorithm to reconstruct the charged tracks for BESⅢ main drift chamber at BEPCⅡ, including the track finding and fitting. With a new method of the Track Segment Finder （TSF）, the results of present study indicate that the algorithm can reconstruct the charged tracks over a wide range of momentum with high efficiency, while improving the robustness against the background noise in the drift chamber. The overall performances, including spatial resolution, momentum resolution and secondary vertices reconstruction efficiency, etc. satisfy the requirements of BESⅢ experiment.
基金Supported by CAS Knowledge Innovation Project(U-602, U-34)National Natural Science Foundation of China (10491300,10491303, 10605030, 10835001, 10821063)+1 种基金100 Talents Program of CAS (U-25 and U-54)National Basic Research Program of China (2009CB825208)
文摘The calibration algorithm for RPC-based muon detector at BESIII has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer, module and strip levels have been calibrated with cosmic ray data. The calibration constants are available for simulation and reconstruction tuning. The results of Monte Carlo and data are also compared to check the validation and reliability of the algorithm.
基金CAS Knowledge Innovation Project (U-602,U-34)National Natural Science Foundation of China (10491300,10491303,10605030)100 Talents Program of CAS (U-25,U-54)
文摘The principle of the method for the BESⅢ event start time determination and the code construction are described. The investigation of influence of the noise, the method of rejecting noise and the performance checking by the Monte Carlo physics data sample are also presented. The preliminary results got from the Monte Carlo simulation are presented, the reconstruction efficiency of J/ψ → anything events at noise level 0 - 60% can achieve above 99%, and the error rate is below 1%.
基金Supported by National Natural Science Foundation of China (10491300, 10491303, 10735080)Research and Development Project of Important Scientific Equipment of CAS (H7292330S7), 100 Talents Programme of CAS (U-25, U-54, U-612)Scientific Research Fund of GUCAS (110200M202)
文摘We established a method on measuring the D^0-D^0 mixing parameter y for BESIII experiment atthe BEPC II e^＋e^- collider. In this method, the doubly tagged 4（3770） D^0-D^0 events, with one D decaysto CP-eigenstates and the other D decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/π separation, a likelihood approach, which combines the dE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of y to be 0.007 based on a 20 fb^-1 fully simulated MC sample.
基金CAS Knowledge Innovation Project(U-602,U-34)National Natural Science Foundation of China(10491300,10491303,10605030)100 Talents Program of CAS (U-25 and.U-54)
文摘The results of a study of event tagging strategies for elementary physics processes in the T-charm region are presented. The algorithm for online event filtering is optimized by adopting the information provided by different sub-detectors according to their strengths and capacities. The algorithm is tested with various generated physics and background events. The results indicate that the algorithm satisfies the requirements of BESⅢ physics analysis and its DAQ system.
基金Supported by CAS Knowledge Innovation Project (U-602, U-34)National Natural Science Foundation of China (10491300,10491303, 10605030)100 Talents Program of CAS (U-25, U-54)
文摘Software alignment is quite important for a tracking detector to reach its ultimate position accuracy and momentum resolution. We developed a new alignment algorithm for the BESⅢ Main Drift Chamber using the Kalman Filter method. Two different types of data which are helix tracks and straight tracks are used to test this algorithm, and the results show that the design and implementation is successful.
基金Supported by CAS Knowledge Innovation Project(U-602, U-34)National Natural Science Foundation of China (10491300,10491303, 10605030)100 Talents Program of CAS (U-25, U-54)
文摘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 algorithm works well and the performance satisfies the physical requirements tested by the simulation data.
