本文介绍了BESIII离线数据处理软件系统的构成以及数据处理的主要流程;给出了利用工具软件TAU(Tuning and Analysis Utilities)对系统性能进行的测试结果,据此结果估算了BESIII实验所需的计算资源,并且与BESIII设计报告的相关部分进行比...本文介绍了BESIII离线数据处理软件系统的构成以及数据处理的主要流程;给出了利用工具软件TAU(Tuning and Analysis Utilities)对系统性能进行的测试结果,据此结果估算了BESIII实验所需的计算资源,并且与BESIII设计报告的相关部分进行比较,说明了BESIII计算机环境的设计基本满足BESIII离线数据处理的要求。展开更多
This article describes the prototype of the read-out subsystem which will be subject to the BESIII data acquisition system. According to the purpose of the BESIII, the event rate will be about 4000 Hz and the data rat...This article describes the prototype of the read-out subsystem which will be subject to the BESIII data acquisition system. According to the purpose of the BESIII, the event rate will be about 4000 Hz and the data rate up to 50 Mbytes/sec after Level 1 trigger. The read-out subsystem consists of some read-out crates and a read-out computer whose function is to initialize the hardware, to collect the event data from the front-end electronics after Level 1 trigger, to transfer data fragments to the computer in online form through two levels of computer pre-processing and high-speed network transmission. In this model, the crate level read-out implementation is based on the commercial single board computer MVME5100 running the VxWorks operating system. The article outlines the structure of the crate level testing platform of hardware and software. It puts emphasis on the framework of the read-out test model, data process flow and test method at crate level. Especially, it enumerates the key technologies in the process of design and analyses the test results. In addition, results which summarize the performance of the single board computer from the data transferring aspects will be presented.展开更多
The prospects to study hyperon-nucleus/nucleon interactions at BESIII and similar e^(+)e^(-)colliders are analyzed in this paper.Utilizing the large quantity of hyperons produced by the decay of 10 billion J/■and 2.7...The prospects to study hyperon-nucleus/nucleon interactions at BESIII and similar e^(+)e^(-)colliders are analyzed in this paper.Utilizing the large quantity of hyperons produced by the decay of 10 billion J/■and 2.7 billion(3686)collected at BESIII,the cross sections of several specific elastic and inelastic hyperon-nucleus reactions can be measured via scattering between hyperons and nucleus in the dense objects of the BESIII detector.Subsequently,the cross sections of the corresponding hyperon-nucleon interactions can be extracted from further phenomenological calculations.The interactions between antihyperons and nucleus/nucleon,including scattering and annihilation,can also be studied using the method proposed in this study.The results will definitely benefit the realization of precise probes for hyperon-nuclei/nucleus interactions and establish constraints to study the potential of strong interaction,the origin of color confinement,a unified model for baryon-baryon interactions,and the internal structure of neutron stars.In addition,the desirable prospects of corresponding studies in the future Super Tau-Charm Factory(STCF)are discussed and estimated in this study.展开更多
The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies ...The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies between 4.009 and 4.946 GeV.Clean deuteron samples are selected using time of flight information.For all data samples,the deuteron identification efficiencies are higher than 95%,with a maximum difference of%between data and Monte Carlo simulation.This verifies the effectiveness of the deuteron identification method based on specific ionization energy loss and provides valuable information for future studies on processes involving deuterons in the final state at BESIII.展开更多
Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,na...Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,namely Bhabha scattering,dimuon production and generic hadronic events with charged particles.The combined efficiency of all active triggers approaches 100%in most cases,with uncertainties small enough not to affect most physics analyses.展开更多
As the main tracking detector of BESIII, the drift chamber provides accurate measurements of the position and the momentum of the charged particles produced in e＋e- collisions at BEPCII. After six years of operation,...As the main tracking detector of BESIII, the drift chamber provides accurate measurements of the position and the momentum of the charged particles produced in e＋e- collisions at BEPCII. After six years of operation, the drift chamber is suffering from aging problems due to huge beam-related background. The gains of the cells in the first ten layers show an obvious decrease, reaching a maximum decrease of about 29% for the first layer cells. Two calculation methods for the gain change （Bhabha events and accumulated charges with 0.3% aging ratio for inner chamber cells） give almost the same results. For the Malter effect encountered by the inner drift chamber in January 2012, about 0.2% water vapor was added to the MDC gas mixture to solve this cathode aging problem. These results provide an important reference for MDC operating high voltage settings and the upgrade of the inner drift chamber.展开更多
Purpose The end cap time of flight(TOF)at Beijing spectrometer was upgraded with multi-gap resistive plate chamber technology in order to improve the particle identification capability in 2015.The offline data quality...Purpose The end cap time of flight(TOF)at Beijing spectrometer was upgraded with multi-gap resistive plate chamber technology in order to improve the particle identification capability in 2015.The offline data quality monitoring is a critical aspect of the data processing chain aiming at providing data with good quality for physics analyses.Methods An offline data quality monitoring tool for upgraded end cap TOF has been developed to provide feedback about the functioning and performance of detector hardware and data processing chain.Results Detector information and reconstructed time-of-flight characteristics of charged tracks are filled into plots using full Bhabha events reconstruction results,and then,these plots are used to assess the operational conditions of the detector and the quality of the data by the experts.Conclusion This paper is describing the design and the content of performance of the offline data quality monitoring of end cap TOF and the data quality performance achieved during last 2 years’physical data taking.展开更多
Considering the effects of aging on the existing Inner Drift Chamber （IDC） of BESIII, a GEM-based inner tracker, the Cylindrical-GEM Inner Tracker （CGEM-IT）, is proposed to be designed and constructed as an upgrad...Considering the effects of aging on the existing Inner Drift Chamber （IDC） of BESIII, a GEM-based inner tracker, the Cylindrical-GEM Inner Tracker （CGEM-IT）, is proposed to be designed and constructed as an upgrade candidate for the IDC. This paper introduces a full simulation package for the CGEM-IT with a simplified digitization model, and describes the development of software for cluster reconstruction and track fitting, using a track fitting algorithm based on the Kalman filter method. Preliminary results for the reconstruction algorithms which are obtained using a Monte Carlo sample of single muon events in the CGEM-IT, show that the CGEM-IT has comparable momentum resolution and transverse vertex resolution to the IDC, and a better z-direction resolution than the IDC.展开更多
A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by ...A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by the new fanning channel, which will degrade the precision of fast control. In this paper, latency uncertainty elimination for the BESIII ETOF upgrade is introduced. The latency uncertainty is determined by a Time-Digital-Converter（TDC） embedded in a Field-Programmable Gate Array（FPGA） and is eliminated by re-capturing at synchronous and determinate time. Compared with the existing method of Barrel-cap TOF（BTOF）, it has advantages of flexible structure, easy calibration and good adaptability. Field tests on the BESIII ETOF system show that this method effectively eliminates transfer latency uncertainty.展开更多
A new inner drift chamber has been built which can replace the aged part of the BESIII drift chamber when needed. The design of the new inner drift chamber can minimize the ineffective area in the very forward and bac...A new inner drift chamber has been built which can replace the aged part of the BESIII drift chamber when needed. The design of the new inner drift chamber can minimize the ineffective area in the very forward and backward region and hence reduce the background event rate. With this design, the new inner drift chamber is expected to have a longer lifetime and improved performance due to the lower occupancy. The endplates and the cylinder were machined with high precision. Wire stringing was performed after the mechanical structure was assembled, and good quality of wire stringing was ensured by measurement of the tension and leakage current of the wires. After completion of the physical construction of the new chamber, a cosmic-ray test was carried out to test its performance. The results of the cosmic-ray test show that the new inner chamber achieves a spatial resolution of127 μm and a d E/dx resolution of 6.4%, which satisfies the design specifications.展开更多
文摘本文介绍了BESIII离线数据处理软件系统的构成以及数据处理的主要流程;给出了利用工具软件TAU(Tuning and Analysis Utilities)对系统性能进行的测试结果,据此结果估算了BESIII实验所需的计算资源,并且与BESIII设计报告的相关部分进行比较,说明了BESIII计算机环境的设计基本满足BESIII离线数据处理的要求。
基金The project supported by Beijing Electron Positron Collider (BEPCII) Upgrade Project
文摘This article describes the prototype of the read-out subsystem which will be subject to the BESIII data acquisition system. According to the purpose of the BESIII, the event rate will be about 4000 Hz and the data rate up to 50 Mbytes/sec after Level 1 trigger. The read-out subsystem consists of some read-out crates and a read-out computer whose function is to initialize the hardware, to collect the event data from the front-end electronics after Level 1 trigger, to transfer data fragments to the computer in online form through two levels of computer pre-processing and high-speed network transmission. In this model, the crate level read-out implementation is based on the commercial single board computer MVME5100 running the VxWorks operating system. The article outlines the structure of the crate level testing platform of hardware and software. It puts emphasis on the framework of the read-out test model, data process flow and test method at crate level. Especially, it enumerates the key technologies in the process of design and analyses the test results. In addition, results which summarize the performance of the single board computer from the data transferring aspects will be presented.
基金Supported by the National Natural Science Foundation of China(NSFC)(11935018,11875054,12165022)the Chinese Academy of Sciences(CAS)Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003)the Fundamental Research Project of Yunnan Province,China(202301AT070162)。
文摘The prospects to study hyperon-nucleus/nucleon interactions at BESIII and similar e^(+)e^(-)colliders are analyzed in this paper.Utilizing the large quantity of hyperons produced by the decay of 10 billion J/■and 2.7 billion(3686)collected at BESIII,the cross sections of several specific elastic and inelastic hyperon-nucleus reactions can be measured via scattering between hyperons and nucleus in the dense objects of the BESIII detector.Subsequently,the cross sections of the corresponding hyperon-nucleon interactions can be extracted from further phenomenological calculations.The interactions between antihyperons and nucleus/nucleon,including scattering and annihilation,can also be studied using the method proposed in this study.The results will definitely benefit the realization of precise probes for hyperon-nuclei/nucleus interactions and establish constraints to study the potential of strong interaction,the origin of color confinement,a unified model for baryon-baryon interactions,and the internal structure of neutron stars.In addition,the desirable prospects of corresponding studies in the future Super Tau-Charm Factory(STCF)are discussed and estimated in this study.
基金Supported by the National Natural Science Foundation of China(11975118,12205141,12375071)。
文摘The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies between 4.009 and 4.946 GeV.Clean deuteron samples are selected using time of flight information.For all data samples,the deuteron identification efficiencies are higher than 95%,with a maximum difference of%between data and Monte Carlo simulation.This verifies the effectiveness of the deuteron identification method based on specific ionization energy loss and provides valuable information for future studies on processes involving deuterons in the final state at BESIII.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012)+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U 1732263,U 1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSWSLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)German Research Foundation DFG under Contracts Nos.Collaborative Research Center CRC 1044,FOR 2359Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development o f Turkey(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DEFG02-05ER41374,DE-SC-0012069)。
文摘Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,namely Bhabha scattering,dimuon production and generic hadronic events with charged particles.The combined efficiency of all active triggers approaches 100%in most cases,with uncertainties small enough not to affect most physics analyses.
基金Supported by the CAS Center for Excellence in Particle Physics(CCEPP)
文摘As the main tracking detector of BESIII, the drift chamber provides accurate measurements of the position and the momentum of the charged particles produced in e＋e- collisions at BEPCII. After six years of operation, the drift chamber is suffering from aging problems due to huge beam-related background. The gains of the cells in the first ten layers show an obvious decrease, reaching a maximum decrease of about 29% for the first layer cells. Two calculation methods for the gain change （Bhabha events and accumulated charges with 0.3% aging ratio for inner chamber cells） give almost the same results. For the Malter effect encountered by the inner drift chamber in January 2012, about 0.2% water vapor was added to the MDC gas mixture to solve this cathode aging problem. These results provide an important reference for MDC operating high voltage settings and the upgrade of the inner drift chamber.
基金Supported in part by National Natural Science Foundation of China(11575225,11875277,U1232201,11605220,U1832204)National Key Basic Research Program of China(2015CB856700)Chinese Academy of Sciences(1G201331231172010).
文摘Purpose The end cap time of flight(TOF)at Beijing spectrometer was upgraded with multi-gap resistive plate chamber technology in order to improve the particle identification capability in 2015.The offline data quality monitoring is a critical aspect of the data processing chain aiming at providing data with good quality for physics analyses.Methods An offline data quality monitoring tool for upgraded end cap TOF has been developed to provide feedback about the functioning and performance of detector hardware and data processing chain.Results Detector information and reconstructed time-of-flight characteristics of charged tracks are filled into plots using full Bhabha events reconstruction results,and then,these plots are used to assess the operational conditions of the detector and the quality of the data by the experts.Conclusion This paper is describing the design and the content of performance of the offline data quality monitoring of end cap TOF and the data quality performance achieved during last 2 years’physical data taking.
基金Supported by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(11205184,11205182)Joint Funds of National Natural Science Foundation of China(U1232201)
文摘Considering the effects of aging on the existing Inner Drift Chamber （IDC） of BESIII, a GEM-based inner tracker, the Cylindrical-GEM Inner Tracker （CGEM-IT）, is proposed to be designed and constructed as an upgrade candidate for the IDC. This paper introduces a full simulation package for the CGEM-IT with a simplified digitization model, and describes the development of software for cluster reconstruction and track fitting, using a track fitting algorithm based on the Kalman filter method. Preliminary results for the reconstruction algorithms which are obtained using a Monte Carlo sample of single muon events in the CGEM-IT, show that the CGEM-IT has comparable momentum resolution and transverse vertex resolution to the IDC, and a better z-direction resolution than the IDC.
基金Supported by CAS Maintenance Project for Major Scientific and Technological Infrastructure(IHEP-SW-953/2013)
文摘A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by the new fanning channel, which will degrade the precision of fast control. In this paper, latency uncertainty elimination for the BESIII ETOF upgrade is introduced. The latency uncertainty is determined by a Time-Digital-Converter（TDC） embedded in a Field-Programmable Gate Array（FPGA） and is eliminated by re-capturing at synchronous and determinate time. Compared with the existing method of Barrel-cap TOF（BTOF）, it has advantages of flexible structure, easy calibration and good adaptability. Field tests on the BESIII ETOF system show that this method effectively eliminates transfer latency uncertainty.
文摘A new inner drift chamber has been built which can replace the aged part of the BESIII drift chamber when needed. The design of the new inner drift chamber can minimize the ineffective area in the very forward and backward region and hence reduce the background event rate. With this design, the new inner drift chamber is expected to have a longer lifetime and improved performance due to the lower occupancy. The endplates and the cylinder were machined with high precision. Wire stringing was performed after the mechanical structure was assembled, and good quality of wire stringing was ensured by measurement of the tension and leakage current of the wires. After completion of the physical construction of the new chamber, a cosmic-ray test was carried out to test its performance. The results of the cosmic-ray test show that the new inner chamber achieves a spatial resolution of127 μm and a d E/dx resolution of 6.4%, which satisfies the design specifications.
