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
In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber （MDC）, a specialized method called TCurlFinder was developed. Thi...In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber （MDC）, a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.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
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 National Natural Science Foundation of China (10821063, 10875141, 10705034, 10605030)Ministry of Science and Technology of China (2009CB825200)+1 种基金Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program (KJCX2-YW-N29, KJCX2-YW-N45)United States Department of Energy (DE-FG02-91ER40682)
文摘In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber （MDC）, a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.
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.
