BESⅢ离线软件与D物理的研究
摘要
北京正负电子对撞机(BEPC)及其大型通用探测器北京谱仪(BES)在2004-2008年间进行了第二次升级改造,并已于2008年中开始运行和实验取数。新升级后的BEPCⅡ是一个高亮度、多束团的双环对撞机,将继续工作在τ-粲能区,其设计峰值亮度比BEPC提高两个数量级,达到10~(33)cm~(-2)s~(-1);BESⅢ探测器基于物理要求,采用了He基气体小单元漂移室、CsI晶体量能器、塑料闪烁体飞行时间计数器、RPCμ子探测器以及基于流水线技术的前端电子学等系统构成,其探测性能相较BESⅡ有了很大提高。基于BEPCⅡ/BESⅢ上将产生的大统计量和高精确度的数据样本,预期能够在弱电相互作用和强相互作用研究、新物理的寻找等问题上取得重要结果。
为配合BEPCⅡ的高亮度,BESⅢ的在线数据获取系统和离线数据分析系统都采用了全新的技术设计和实现,如面向对象的C++程序开发语言、高能物理通用软件框架Gaudi等技术的使用,在软件重用、模块化的设计和开发以及代码维护等多方面为我们带来了便利。另外,与D_((s))介子相关的D物理研究是BESⅢ数据分析工作的重要组成部分。在现阶段,对D物理分析使用的软件工具的开发,将为未来D物理工作的正常开展提供基础。
当BEPCⅡ在设计峰值亮度运行时,BESⅢ中事例率将高达10~7 Hz。为了压低数据中各种来源的本底事例以减轻数据存储系统的压力,有必要在取数的同时对事例进行筛选;此外在计算资源允许的情况下,还可以对我们感兴趣的物理事例分类和标记。为此,我们在第一级硬件快速触发系统的基础上,实现了第二级事例筛选软件系统。事例筛选软件框架在设计时充分考虑了软件模块与运行环境的分离问题,将与在线环境耦合部分以接口的形式提供,而其流程控制功能核心组件则实现为和环境无关的独立模块。这样,流程控制组件不仅能做为在线事例筛选软件的一部分运行于在线环境,还能直接运行于离线软件框架中,提高了软件的重用性,也方便了事例筛选算法在离线环境中的开发。我们还为流程控制组件实现了强大的逻辑控制能力,使其能使用各种筛选算法和条件的灵活组合;同时使用XML格式的配置文件,以简析的规则实现对流程控制的完全配置。事例筛选软件已经运行于BESⅢ实时在线取数环境中,运行稳定且结果基本可靠。在将来,事例筛选算法和筛选条件还需要根据实验数据的实际情况不断调试和完善,以进一步提高其性能和可靠性。
在线数据获取系统完成取数后,将原始数据存人磁盘或磁带供离线数据处理任务使用。原始数据是以特定格式压缩编码的探测器电子学读出信息,以二进制数据流形式保存。为了方便离线软件对原始数据的访问,我们开发了基于Gaudi的原始数据转换服务,它为用户隐藏了格式相关的复杂细节,而是提供了一致的数据访问接口。它主要用于完成数据的解码,将电子学压缩信息还原为探测器中的时间和电荷信号;另外也具有数据输出功能,能够把模拟数据存储为原始数据格式。为能在一些在线软件中重用原始数据转换服务的功能,我们为其提供了在线和离线两种编译模式,其中的在线模式运行时从网络获取事例数据,然后完成格式解析过程。为缓解数据服务器的磁盘I/O和网络瓶颈问题,还对转换服务进行了优化,包括添加文件缓存和使用第三方库对文件进一步压缩等,起到了积极效果。开发了原始数据过滤服务对原始数据进行预处理,离线任务可根据需要,排除数据中部分不满足规范的击中信息。BESⅢ探测器自开始取数以来,已积累了超过2 TB的原始数据,在这些数据的处理过程中,原始数据转换服务运行稳定、结果可靠,符合BESⅢ实验的需求。
BEPCⅡ在设计亮度运行时,每年将能产生约3×10~7 D(?)介子对,数据的有效利用需要对D介子的高效重建。我们将使用到大量的D介子强衰变过程,以在保证重建质量的前提下提高重建效率。为能简化重建程序的开发、维护和使用,参考CLEO-c D-tagging软件思想,结合BOSS框架的结构和特点,设计了BESⅢ的D-tagging软件框架。使用D-tagging成功重建的D介子称为D标记,通常的D物理研究都应从D标记开始。D-tagging框架分为粒子列表、组合器和D标记的存储访问三个功能模块,其中的粒子列表和组合器在BesDChain软件包中集成实现。BesDChain是D-tagging软件的重要组成部分,然而,它事实上独立于D介子的标记,可以做为一个通用的软件工具用于任意衰变过程的重建。BesDChain能大大简化事例重建代码的编写、特别是复杂衰变过程。BesDChain在实现时大量使用了C++语言的模板技术,在很大程度上避免了功能相似代码的重复开发;另外还在很多场合使用了懒惰计算法(lazyevaluation),避免了计算资源的浪费。目前,BesDChain的所有预期基本功能均已实现,且能够和BOSS现有软件系统很好的融合,D标记存储访问的研究也正在进行中。以BesDChain为基础,D标记算法的开发即将在后续工作中展开。
D介子衰变到两个矢量介子时,对其两个子粒子角分布的测量能为CP破坏的研究提供信息。为了从D~+→(?)~*(892)~0ρ~+(+c.c.)衰变中提取分支比以及D介子的纵向极化比率f_L,开发了多变量拟合软件工具包D2vvTools。为了区分信号和本底,使用了ΔE、m_(bc)、m_(K~*)和m_ρ四个参量;D~+在纵向和横向极化时,其子粒子K~*和ρ~+的衰变角θ_1和θ_2有不同的分布,θ_1和θ_2被用于f_L的测量。这样,D2vvTools总共使用了6个变量做为拟合参数。对每个参数的概率密度函数(PDF)都使用MC数据进行参数化和确定。为能精确描述数据的分布情况,我们不但把数据划分为信号和本底,还将信号进一步细化为真实信号和Self Cross Feed(SCF)组分。假定参与拟合的6个变量相互没有关联,它们的联合PDF将能通过各单变量PDF的乘积得到。我们把80%纵向极化和20%横向极化的模拟信号混合,测试了D2vvTools对极化比率的分辨能力,得到f_L=(80.4±0.5)%。目前对本底只做了初步检查,将来还需要更多深入研究,以对本底进行细致的分类和理解。
本文最后还回顾了不同实验对衰变常数f_(D_s~+)的最新测量结果,发现其实验值相对格点QCD(LQCD)理论预言值有约4σ水平的偏差。同时,R_μ三BR(D_s~+→μ~+v_μ)/BR(D~+→μ~+v_μ)也比标准模型的预言偏大2σ水平。2HDM理论的预言与这些实验结果不相一致,而R_μ实验与理论值的偏差暗示了新物理的可能存在。我们讨论了未来在BESⅢ上对R_μ进行精确测量的可行性。使用ψ(3770)数据中完整标记的D~+以及质心能量在4.170 GeV处数据中完整标记的D_s~+,经过约四年的数据积累,BESⅢ将能把R_μ的精确度控制在1%水平。通过比较精确测量的R_μ实验值及其理论(特别是LQCD)预言值,将为新物理的发现带来机会。
The Beijing Electron Position Collider(BEPC) and Beijing Spectrometer(BES) have been upgraded again during the year 2004-2008,and have began to run since the middle of 2008.The newly upgraded BEPCⅡis a multi-bunch and double ring collider with designed peak luminosity of 10~(33)cm~(-2)s~(-1),an improvement of a factor of 100 with respect to BEPC.The BESⅢdetector mainly consists of a multilayer drift chamber,a plastic scintillator time-of-flight system,a CsⅠelectromagnetic calorimeter and a RPC-based muon identifier.Comparing with the previous BESⅡdetector,the performance of BESⅢhas significantly improved.With the large sample and high precise data that will be produced by BEPCⅡ/BESⅢ,it's expected to achieve great results on the topics of eletroweak and strong interactions,search for new physics,et al.
In order to meet the high luminosity of BEPCⅡ,the online DAQ and offline data processing systems are completely redesigned and implemented with new technologies. The adoption of object-oriented C++ programming language and Gaudi framework brings us great conveniences in many areas,such as the software reuse,code maintenances,and the modularization design and implementation.The D physics, which corresponds to the researches of D_((s)) mesons,is an important part of BESⅢphysics analysis.The development of toolkits for D physics from now on will play an important role in the future researches.
When BEPCⅡruns at the designed peak luminosity,the event rate will reach 10~7 Hz.We have to filter these events so to reduce the various sources of background and ease the data storage system.Furthermore,we can also classify and tag the events that we are interested at the same time.To achieve this requirement,we applied a high level event filtering software system in addition to the first level fast trigger system.For the event filtering will be used in both the online and offline environments,we carefully designed the framework in order to maximize the software reuse.The framework is divided into 2 parts:the 1~(st) part is realized as an interface of the online environment; and the 2~(nd) part,which is named as step-handler and contains the main functionality of event filtering procedures,is realized as an environment independent module.The step-handler can execute as part of the online event filtering software,as well as execute directly in the offline BOSS framework.With the step-handler,various filtering algorithms and criterions can be used and fully configured by XML files.The event filtering software has been involved since the beginning of BESⅢoperation,and the results are basically reliable.In future,the filtering algorithms and criterions should be optimized continuously according to the real data status.
The electronic signals from detectors are coded and compressed with specific format,and then stored to disks or tapes as the binary raw data.In order to simplify the access to raw data by offline software,we developed the raw data conversion service. The complex details of the data format are hidden,and the compressed signals are decoded by the conversion service,so that users can access data with simple interfaces. Besides that,the conversion service can also be used to save the simulated data as raw format.For some online software have to reuse the raw data conversion service,we provide 2 different compiling mode to it,the offiine mode and the online mode.When it's compiled as online mode,the input data are received via the intranet instead of read from disks.We optimized the conversion service by adding a file buffer and reducing the data size with third-party library,and these efforts eased the data I/O bottleneck to a certain extent.We developed an additional data provider service to preprocessing the raw data,which is used to reject some abnormal signals.We have got more than 2 TB raw data since the BESⅢbegin to run,the conversion service works steadily and reliably during the data processing.It meets the requirements of BESⅢ.
In the future,3×10~7 D(?) pairs will be produced each year at BESⅢ.We need to reconstruct the D mesons via a lot of hadronic modes to improve the efficiency,so as to use the data effectively.In order to simplify the development,maintenance and the usage of the reconstruction program,we designed the BESⅢD-tagging framework referred to the CLEO-c D-tagging software.The D meson reconstructed by the D-tagging software is called D-tag.Generally,all D physics researches should start from the D-tags.The framework is consists of particle list,combinatoric engine and the tag storage.The particle list and combinatoric engine are compositively implemented in the BesDChain package.BesDChain is an important component of the D-tagging software, however,it can be used as a general purpose toolkit in fact.The BesDChain will simplify reconstruction algorithms greatly,especially to complex decay channels.In BesDChain,C++ class templates are widely used to avoid similar code development; and lazy evaluations are adopted in many areas to avoid the waste of computing resources. The development of BesDChain has been finished,and it can cooperate with BOSS seamlessly.Based on the BesDChain,the tag storage and D reconstruction algorithms are being studied.
When a D meson decays to 2 vector mesons,the decay angle of the 2 children are of great interest,for it can be used to measure the CP violation.To extract the decay rate and the longitudinal polarization fraction f_L of the D meson from the decay of D~+→(?)~*(892)~0ρ~+(+ c.c.),a multi-variable fitting toolkit named D2vvTools is developed.VariablesΔE,m_(bc),m_(K~*) and m_ρare used to distinguish backgrounds from signal,and the decay angle of K~*(892)~0andρ~+(θ_1 andθ_2) are used to distinguish the longitudinal polarized components from the transverse polarized components.So, totally 6 variables are used in D2vvTools.The parameterized PDF(probability density function) of each variable is determined by using MC data.In order to describe the data distribution precisely,besides the background,the signal are ulteriorly divided into true-signal and self-cross-feed(SCF) components.It's assumed that the 6 variables are uncorrelated,so the joint PDF for each component can be obtained by the product of sigle-variable PDFs.We mixed 80%longitudinal and 20%transverse polarized MC signal data to test the D2vvTools toolkit,and get f_L=(80.4±0.5)%.Currently we only made some simple check to the background.More studies of the background will undertake in the future.
At the end of this thesis,we reviewed the most recent determinations of the decay constant f_(D_s~+) from different experiments.We find that the current experimental determination in the SM context differs from the most precise unquenched lattice QCD(LQCD) calculation at a 4σlevel.Meanwhile,the measured ratio,R_μ≡ BR(D_s~+→μ~+ν_μ)/BR(D~+→μ~+ν_μ),is larger than the SM prediction at a 2.0σlevel. With current data,the occurrence of new physics,in the case of the 2HDM,is disfavored. The measured ratio R_μsuggests that we need a new physics contribution with constructive interference.We discuss that the precise measurement of R_μat BESⅢwill shed light on the presence of new intermediate particles by comparing with the theoretical predictions,especially the LQCD calculations.
为配合BEPCⅡ的高亮度,BESⅢ的在线数据获取系统和离线数据分析系统都采用了全新的技术设计和实现,如面向对象的C++程序开发语言、高能物理通用软件框架Gaudi等技术的使用,在软件重用、模块化的设计和开发以及代码维护等多方面为我们带来了便利。另外,与D_((s))介子相关的D物理研究是BESⅢ数据分析工作的重要组成部分。在现阶段,对D物理分析使用的软件工具的开发,将为未来D物理工作的正常开展提供基础。
当BEPCⅡ在设计峰值亮度运行时,BESⅢ中事例率将高达10~7 Hz。为了压低数据中各种来源的本底事例以减轻数据存储系统的压力,有必要在取数的同时对事例进行筛选;此外在计算资源允许的情况下,还可以对我们感兴趣的物理事例分类和标记。为此,我们在第一级硬件快速触发系统的基础上,实现了第二级事例筛选软件系统。事例筛选软件框架在设计时充分考虑了软件模块与运行环境的分离问题,将与在线环境耦合部分以接口的形式提供,而其流程控制功能核心组件则实现为和环境无关的独立模块。这样,流程控制组件不仅能做为在线事例筛选软件的一部分运行于在线环境,还能直接运行于离线软件框架中,提高了软件的重用性,也方便了事例筛选算法在离线环境中的开发。我们还为流程控制组件实现了强大的逻辑控制能力,使其能使用各种筛选算法和条件的灵活组合;同时使用XML格式的配置文件,以简析的规则实现对流程控制的完全配置。事例筛选软件已经运行于BESⅢ实时在线取数环境中,运行稳定且结果基本可靠。在将来,事例筛选算法和筛选条件还需要根据实验数据的实际情况不断调试和完善,以进一步提高其性能和可靠性。
在线数据获取系统完成取数后,将原始数据存人磁盘或磁带供离线数据处理任务使用。原始数据是以特定格式压缩编码的探测器电子学读出信息,以二进制数据流形式保存。为了方便离线软件对原始数据的访问,我们开发了基于Gaudi的原始数据转换服务,它为用户隐藏了格式相关的复杂细节,而是提供了一致的数据访问接口。它主要用于完成数据的解码,将电子学压缩信息还原为探测器中的时间和电荷信号;另外也具有数据输出功能,能够把模拟数据存储为原始数据格式。为能在一些在线软件中重用原始数据转换服务的功能,我们为其提供了在线和离线两种编译模式,其中的在线模式运行时从网络获取事例数据,然后完成格式解析过程。为缓解数据服务器的磁盘I/O和网络瓶颈问题,还对转换服务进行了优化,包括添加文件缓存和使用第三方库对文件进一步压缩等,起到了积极效果。开发了原始数据过滤服务对原始数据进行预处理,离线任务可根据需要,排除数据中部分不满足规范的击中信息。BESⅢ探测器自开始取数以来,已积累了超过2 TB的原始数据,在这些数据的处理过程中,原始数据转换服务运行稳定、结果可靠,符合BESⅢ实验的需求。
BEPCⅡ在设计亮度运行时,每年将能产生约3×10~7 D(?)介子对,数据的有效利用需要对D介子的高效重建。我们将使用到大量的D介子强衰变过程,以在保证重建质量的前提下提高重建效率。为能简化重建程序的开发、维护和使用,参考CLEO-c D-tagging软件思想,结合BOSS框架的结构和特点,设计了BESⅢ的D-tagging软件框架。使用D-tagging成功重建的D介子称为D标记,通常的D物理研究都应从D标记开始。D-tagging框架分为粒子列表、组合器和D标记的存储访问三个功能模块,其中的粒子列表和组合器在BesDChain软件包中集成实现。BesDChain是D-tagging软件的重要组成部分,然而,它事实上独立于D介子的标记,可以做为一个通用的软件工具用于任意衰变过程的重建。BesDChain能大大简化事例重建代码的编写、特别是复杂衰变过程。BesDChain在实现时大量使用了C++语言的模板技术,在很大程度上避免了功能相似代码的重复开发;另外还在很多场合使用了懒惰计算法(lazyevaluation),避免了计算资源的浪费。目前,BesDChain的所有预期基本功能均已实现,且能够和BOSS现有软件系统很好的融合,D标记存储访问的研究也正在进行中。以BesDChain为基础,D标记算法的开发即将在后续工作中展开。
D介子衰变到两个矢量介子时,对其两个子粒子角分布的测量能为CP破坏的研究提供信息。为了从D~+→(?)~*(892)~0ρ~+(+c.c.)衰变中提取分支比以及D介子的纵向极化比率f_L,开发了多变量拟合软件工具包D2vvTools。为了区分信号和本底,使用了ΔE、m_(bc)、m_(K~*)和m_ρ四个参量;D~+在纵向和横向极化时,其子粒子K~*和ρ~+的衰变角θ_1和θ_2有不同的分布,θ_1和θ_2被用于f_L的测量。这样,D2vvTools总共使用了6个变量做为拟合参数。对每个参数的概率密度函数(PDF)都使用MC数据进行参数化和确定。为能精确描述数据的分布情况,我们不但把数据划分为信号和本底,还将信号进一步细化为真实信号和Self Cross Feed(SCF)组分。假定参与拟合的6个变量相互没有关联,它们的联合PDF将能通过各单变量PDF的乘积得到。我们把80%纵向极化和20%横向极化的模拟信号混合,测试了D2vvTools对极化比率的分辨能力,得到f_L=(80.4±0.5)%。目前对本底只做了初步检查,将来还需要更多深入研究,以对本底进行细致的分类和理解。
本文最后还回顾了不同实验对衰变常数f_(D_s~+)的最新测量结果,发现其实验值相对格点QCD(LQCD)理论预言值有约4σ水平的偏差。同时,R_μ三BR(D_s~+→μ~+v_μ)/BR(D~+→μ~+v_μ)也比标准模型的预言偏大2σ水平。2HDM理论的预言与这些实验结果不相一致,而R_μ实验与理论值的偏差暗示了新物理的可能存在。我们讨论了未来在BESⅢ上对R_μ进行精确测量的可行性。使用ψ(3770)数据中完整标记的D~+以及质心能量在4.170 GeV处数据中完整标记的D_s~+,经过约四年的数据积累,BESⅢ将能把R_μ的精确度控制在1%水平。通过比较精确测量的R_μ实验值及其理论(特别是LQCD)预言值,将为新物理的发现带来机会。
The Beijing Electron Position Collider(BEPC) and Beijing Spectrometer(BES) have been upgraded again during the year 2004-2008,and have began to run since the middle of 2008.The newly upgraded BEPCⅡis a multi-bunch and double ring collider with designed peak luminosity of 10~(33)cm~(-2)s~(-1),an improvement of a factor of 100 with respect to BEPC.The BESⅢdetector mainly consists of a multilayer drift chamber,a plastic scintillator time-of-flight system,a CsⅠelectromagnetic calorimeter and a RPC-based muon identifier.Comparing with the previous BESⅡdetector,the performance of BESⅢhas significantly improved.With the large sample and high precise data that will be produced by BEPCⅡ/BESⅢ,it's expected to achieve great results on the topics of eletroweak and strong interactions,search for new physics,et al.
In order to meet the high luminosity of BEPCⅡ,the online DAQ and offline data processing systems are completely redesigned and implemented with new technologies. The adoption of object-oriented C++ programming language and Gaudi framework brings us great conveniences in many areas,such as the software reuse,code maintenances,and the modularization design and implementation.The D physics, which corresponds to the researches of D_((s)) mesons,is an important part of BESⅢphysics analysis.The development of toolkits for D physics from now on will play an important role in the future researches.
When BEPCⅡruns at the designed peak luminosity,the event rate will reach 10~7 Hz.We have to filter these events so to reduce the various sources of background and ease the data storage system.Furthermore,we can also classify and tag the events that we are interested at the same time.To achieve this requirement,we applied a high level event filtering software system in addition to the first level fast trigger system.For the event filtering will be used in both the online and offline environments,we carefully designed the framework in order to maximize the software reuse.The framework is divided into 2 parts:the 1~(st) part is realized as an interface of the online environment; and the 2~(nd) part,which is named as step-handler and contains the main functionality of event filtering procedures,is realized as an environment independent module.The step-handler can execute as part of the online event filtering software,as well as execute directly in the offline BOSS framework.With the step-handler,various filtering algorithms and criterions can be used and fully configured by XML files.The event filtering software has been involved since the beginning of BESⅢoperation,and the results are basically reliable.In future,the filtering algorithms and criterions should be optimized continuously according to the real data status.
The electronic signals from detectors are coded and compressed with specific format,and then stored to disks or tapes as the binary raw data.In order to simplify the access to raw data by offline software,we developed the raw data conversion service. The complex details of the data format are hidden,and the compressed signals are decoded by the conversion service,so that users can access data with simple interfaces. Besides that,the conversion service can also be used to save the simulated data as raw format.For some online software have to reuse the raw data conversion service,we provide 2 different compiling mode to it,the offiine mode and the online mode.When it's compiled as online mode,the input data are received via the intranet instead of read from disks.We optimized the conversion service by adding a file buffer and reducing the data size with third-party library,and these efforts eased the data I/O bottleneck to a certain extent.We developed an additional data provider service to preprocessing the raw data,which is used to reject some abnormal signals.We have got more than 2 TB raw data since the BESⅢbegin to run,the conversion service works steadily and reliably during the data processing.It meets the requirements of BESⅢ.
In the future,3×10~7 D(?) pairs will be produced each year at BESⅢ.We need to reconstruct the D mesons via a lot of hadronic modes to improve the efficiency,so as to use the data effectively.In order to simplify the development,maintenance and the usage of the reconstruction program,we designed the BESⅢD-tagging framework referred to the CLEO-c D-tagging software.The D meson reconstructed by the D-tagging software is called D-tag.Generally,all D physics researches should start from the D-tags.The framework is consists of particle list,combinatoric engine and the tag storage.The particle list and combinatoric engine are compositively implemented in the BesDChain package.BesDChain is an important component of the D-tagging software, however,it can be used as a general purpose toolkit in fact.The BesDChain will simplify reconstruction algorithms greatly,especially to complex decay channels.In BesDChain,C++ class templates are widely used to avoid similar code development; and lazy evaluations are adopted in many areas to avoid the waste of computing resources. The development of BesDChain has been finished,and it can cooperate with BOSS seamlessly.Based on the BesDChain,the tag storage and D reconstruction algorithms are being studied.
When a D meson decays to 2 vector mesons,the decay angle of the 2 children are of great interest,for it can be used to measure the CP violation.To extract the decay rate and the longitudinal polarization fraction f_L of the D meson from the decay of D~+→(?)~*(892)~0ρ~+(+ c.c.),a multi-variable fitting toolkit named D2vvTools is developed.VariablesΔE,m_(bc),m_(K~*) and m_ρare used to distinguish backgrounds from signal,and the decay angle of K~*(892)~0andρ~+(θ_1 andθ_2) are used to distinguish the longitudinal polarized components from the transverse polarized components.So, totally 6 variables are used in D2vvTools.The parameterized PDF(probability density function) of each variable is determined by using MC data.In order to describe the data distribution precisely,besides the background,the signal are ulteriorly divided into true-signal and self-cross-feed(SCF) components.It's assumed that the 6 variables are uncorrelated,so the joint PDF for each component can be obtained by the product of sigle-variable PDFs.We mixed 80%longitudinal and 20%transverse polarized MC signal data to test the D2vvTools toolkit,and get f_L=(80.4±0.5)%.Currently we only made some simple check to the background.More studies of the background will undertake in the future.
At the end of this thesis,we reviewed the most recent determinations of the decay constant f_(D_s~+) from different experiments.We find that the current experimental determination in the SM context differs from the most precise unquenched lattice QCD(LQCD) calculation at a 4σlevel.Meanwhile,the measured ratio,R_μ≡ BR(D_s~+→μ~+ν_μ)/BR(D~+→μ~+ν_μ),is larger than the SM prediction at a 2.0σlevel. With current data,the occurrence of new physics,in the case of the 2HDM,is disfavored. The measured ratio R_μsuggests that we need a new physics contribution with constructive interference.We discuss that the precise measurement of R_μat BESⅢwill shed light on the presence of new intermediate particles by comparing with the theoretical predictions,especially the LQCD calculations.
引文
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[2]李政道,粒子物理和场论简引,科学出版社,第一版,1984;
L.赖得,基本粒子与对称性,科学出版社,第一版,1983
[3]D.J.Gross and F.Wilczek,Phys.Lett.30,1343(1973);
H.D.Politzer,Phys.Rev.Lett.30,1346(1973)
[4]郑志鹏等,北京谱仪正负电子物理,广西科学计数出版社,第一版,1998
[5]谢一冈等,粒子探测器与数据获取,科学出版社,2003年7月
[6]http://public.web.cern.ch/Public/en/LHC/LHC-en.html
[7]PEPⅡ- An Asymmetric B Factory,Conceptual Design Report.SLAC-418,LBL-5379,1993
[8]BaBar Collaboration.BaBar Technical Design Report.SLAC-R-457,1995
[9]KEKB B-Factory Design Report.KEK Report 95-7,1995
[10]Belle Collaboration,Belle Technical Design Report,KEK Report 95-1,1995
[11]G.Vignola and DAFNE Project Team.DAFNE,The First Phi-Factory.LNF-96/033,1996
[12]KLOE Collaboration.The KLOE Detector Technical Proposal.LNF-93/2,1993
[13]北京正负电子对撞机重大改造工程BEPCⅡ初步设计,2003年11月
[14]BES Ⅲ Collaboration.The Preliminary Design Report of the BES Ⅲ Detector.Report No.IHEP-BEPCⅡ-SB-13.Jan,2004
[15]唐孝威等,粒子物理实验方法,人民教育出版社,第一版,1982
[16]Li Wei-Guo,BEPCⅡBES Ⅲ Upgrade and the Prospective Physics,
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[21]Preliminary Design Report:The BES Ⅲ Detector.2004:193-208.
[22]Preliminary Design Report:The BES Ⅲ Detector.2004:170-192.
[23]Preliminary Design Report:The BES Ⅲ Detector.2004:269-290.
[24]Preliminary Design Report:The BES Ⅲ Detector.2004:291-300.
[25]Gaudi project homepage:http://proj-gaudi.web.cern.ch/proj-gaudi/
[26]Weidong Li,Huaimin Liu et al.The Offline Software for the BES Ⅲ Experiment,Proceeding of CHEP06,Mumbai,2006.
[27]Deng Zi-Yan et al.HEP&NP,2006,30(05):371-377(in Chinese)
(邓子艳等,高能物理核物理,2006,30(05):371-377)
[28]Agostinelli,S.and Allison em et al GEANT4-a simulation toolkit,Nucl.Instrum.Methods A,2003,506:250-303.
[29]Mao Ze-Pu,Introduction of the BESⅢ Event Reconstruction System,BESⅢCollaboration Meeting,2008.
[30]He Kang-Lin,Status of Tools software,BESⅢ Collaboration Meeting,2008.
[31]Preliminary Design Report:The BES Ⅲ Detector.2004:209-268.
[32]You Zheng-Yun,BES Ⅲ Detector Description and Event Display,BES Ⅲ Collaboration Meeting,2006.
[33]徐昊等,BESⅢ触发系统MDC子系统的物理设计.高能物理与核物理,2005,29(4):376-382
[34]刘英杰,邹佳恒等,BESⅢ事例筛选软件框架.核电子学与探测技术,2007,27(6):1035-1039
[35]Fu Cheng-Dong,Zou Jia-Heng,et al.,Study of the Online Event Filtering Algorithm for BES Ⅲ,Chinese Physics C(HEP & NP),2008 32(05):329-337
[36]汤睿等,BESⅢ在线事例选择流程控制.核电子学与探测技术,2006,26(1):95-99
[37]Extensible Markup Language(XML),http://www.w3.org/XML/
[38]Xerces-C++ XML Parser,http://xerces.apache.org/xerces-c
[39]BESⅢ DAQ Group,BESⅢ在线数据格式说明.v1.1,2007年4月
[40]张晓梅等,基于GAUDI框架的原始数据管理系统.高能物理与核物理,2005,29(12):1170-1174
[41]zlib,http://www.zlib.net
[42] D.M. Asner et al. 2008, arXiv:0809.1869v1 [hep-ex]; IHEP-Physics-Report-BES-III-2008-001-v1: Charm production and D tagging.
[43] Peter ZWEBER, Charm Group and D Tag Report. BES-III Collaboration Meeting, 2009
[44] Scott Meyers, More Effective C++, Item 17: Consider using lazy evaluation
[45] C. D. Jones. 2003, arXiv:hep-ex/0305090v1
[46] B. Cheng et al. BaBar Analysis Document # 892, Version 16.2005.
[47] Root - an object-oriented data analysis framework. http://root.cern.ch/
[48] The RooFit packages, http://roofit.sourceforge.net/
[49] Akeroyd A G, CHEN C H. Phys. Rev. D, 2007,75: 075004; Akeroyd A G. Prog. Theor. Phys., 2004, 111: 295
[50] Rosner J L, Stone S. arXiv:0802.1043v2 [hep-ex]; Rosner J L, Stone S. Phys. Lett. B, 2008, 667:1
[51] Ikado K et al. (Belle Collaboration). Phys. Rev. Lett., 2006, 97: 251802
[52] Aubert B et al. (BaBar Collaboration). arXiv:0705.1820; Aubert B et al. (BaBar Collaboration). Phys. Rev. D, 2007,76: 052002
[53] YAO W M et al. (Partcle Data Group). J. Phys. G, 2006, 33: 1
[54] Artuso M et al. (CLEO Collaboration). Phys. Rev. Lett., 2005,95: 251801
[55] Artuso M et al. (CLEO Collaboration). Phys. Rev. Lett., 2007, 99: 071802
[56] Ecklund K M et al. (CLEO Collaboration). arXiv:0712.1175, 2007
[57] Aubert B et al. (BABAR Collaboration). Phys. Rev. Lett., 2007,98: 141801
[58] Abe K et al. (Belle Collaboration). arXiv:0709.1340, 2007
[59] Follana E et al. (HPQCD and UKQCD Collaboration). arXiv:0706.1726,2007
[60] Aubin C et al. (MILC Collaboration). Phys. Rev. Lett., 2005, 95: 122002
[61] Ali Khan A et al. (QCDSF Collaboration). Phys. Lett. B, 2007, 652: 150
[62] Chiu T W et al. Phys. Lett. B, 2005, 624: 31
[63] Lellouch L, LIN C J. Phys. Rev. D, 2001, 64: 094501
[64] Dobrescu B A, Kronfeld A S. arXiv:0803.0512 [hep-ph]
[65] LI H B. Nucl. Phys. B, 2006, Proc. Suppl. 162: 312
[66] Poling P. Invited Talk at 4th Flavor Physics and CP Violation Conference (FPCP 2006). Vancouver, British Columbia, Canada, 9-12 Apr 2006; In the Proceedings of 4th Flavor Physics and CP Violation Conference (FPCP 2006). Vancouver, British Columbia, Canada, 9-12 Apr 2006, hep-ex/0606016
[67] Asner D M. Proceedings of the CHARM2007 Workshop. Ithaca, NY, Auguest 5-8, 2007. arXiv:0711.3044
[68] Pedlar T K et al. (CLEO Collaboration). Phys. Rev. D, 2007, 76: 072002
[69] HE Q et al. (CLEO Collaboration). Phys. Rev. Lett., 2005,95: 121801; 2006,96: 199903
[70] Burdman G, Goldman T, Wyler D. Phys. Rev. D, 1995,51: 111
[2]李政道,粒子物理和场论简引,科学出版社,第一版,1984;
L.赖得,基本粒子与对称性,科学出版社,第一版,1983
[3]D.J.Gross and F.Wilczek,Phys.Lett.30,1343(1973);
H.D.Politzer,Phys.Rev.Lett.30,1346(1973)
[4]郑志鹏等,北京谱仪正负电子物理,广西科学计数出版社,第一版,1998
[5]谢一冈等,粒子探测器与数据获取,科学出版社,2003年7月
[6]http://public.web.cern.ch/Public/en/LHC/LHC-en.html
[7]PEPⅡ- An Asymmetric B Factory,Conceptual Design Report.SLAC-418,LBL-5379,1993
[8]BaBar Collaboration.BaBar Technical Design Report.SLAC-R-457,1995
[9]KEKB B-Factory Design Report.KEK Report 95-7,1995
[10]Belle Collaboration,Belle Technical Design Report,KEK Report 95-1,1995
[11]G.Vignola and DAFNE Project Team.DAFNE,The First Phi-Factory.LNF-96/033,1996
[12]KLOE Collaboration.The KLOE Detector Technical Proposal.LNF-93/2,1993
[13]北京正负电子对撞机重大改造工程BEPCⅡ初步设计,2003年11月
[14]BES Ⅲ Collaboration.The Preliminary Design Report of the BES Ⅲ Detector.Report No.IHEP-BEPCⅡ-SB-13.Jan,2004
[15]唐孝威等,粒子物理实验方法,人民教育出版社,第一版,1982
[16]Li Wei-Guo,BEPCⅡBES Ⅲ Upgrade and the Prospective Physics,
[17]Preliminary Design Report:The BES Ⅲ Detector.2004:62-83.
[18]Preliminary Design Report:The BES Ⅲ Detector.2004:84-118.
[19]Preliminary Design Report:The BES Ⅲ Detector.2004:119-133.
[20]Preliminary Design Report:The BES Ⅲ Detector.2004:134-169.
[21]Preliminary Design Report:The BES Ⅲ Detector.2004:193-208.
[22]Preliminary Design Report:The BES Ⅲ Detector.2004:170-192.
[23]Preliminary Design Report:The BES Ⅲ Detector.2004:269-290.
[24]Preliminary Design Report:The BES Ⅲ Detector.2004:291-300.
[25]Gaudi project homepage:http://proj-gaudi.web.cern.ch/proj-gaudi/
[26]Weidong Li,Huaimin Liu et al.The Offline Software for the BES Ⅲ Experiment,Proceeding of CHEP06,Mumbai,2006.
[27]Deng Zi-Yan et al.HEP&NP,2006,30(05):371-377(in Chinese)
(邓子艳等,高能物理核物理,2006,30(05):371-377)
[28]Agostinelli,S.and Allison em et al GEANT4-a simulation toolkit,Nucl.Instrum.Methods A,2003,506:250-303.
[29]Mao Ze-Pu,Introduction of the BESⅢ Event Reconstruction System,BESⅢCollaboration Meeting,2008.
[30]He Kang-Lin,Status of Tools software,BESⅢ Collaboration Meeting,2008.
[31]Preliminary Design Report:The BES Ⅲ Detector.2004:209-268.
[32]You Zheng-Yun,BES Ⅲ Detector Description and Event Display,BES Ⅲ Collaboration Meeting,2006.
[33]徐昊等,BESⅢ触发系统MDC子系统的物理设计.高能物理与核物理,2005,29(4):376-382
[34]刘英杰,邹佳恒等,BESⅢ事例筛选软件框架.核电子学与探测技术,2007,27(6):1035-1039
[35]Fu Cheng-Dong,Zou Jia-Heng,et al.,Study of the Online Event Filtering Algorithm for BES Ⅲ,Chinese Physics C(HEP & NP),2008 32(05):329-337
[36]汤睿等,BESⅢ在线事例选择流程控制.核电子学与探测技术,2006,26(1):95-99
[37]Extensible Markup Language(XML),http://www.w3.org/XML/
[38]Xerces-C++ XML Parser,http://xerces.apache.org/xerces-c
[39]BESⅢ DAQ Group,BESⅢ在线数据格式说明.v1.1,2007年4月
[40]张晓梅等,基于GAUDI框架的原始数据管理系统.高能物理与核物理,2005,29(12):1170-1174
[41]zlib,http://www.zlib.net
[42] D.M. Asner et al. 2008, arXiv:0809.1869v1 [hep-ex]; IHEP-Physics-Report-BES-III-2008-001-v1: Charm production and D tagging.
[43] Peter ZWEBER, Charm Group and D Tag Report. BES-III Collaboration Meeting, 2009
[44] Scott Meyers, More Effective C++, Item 17: Consider using lazy evaluation
[45] C. D. Jones. 2003, arXiv:hep-ex/0305090v1
[46] B. Cheng et al. BaBar Analysis Document # 892, Version 16.2005.
[47] Root - an object-oriented data analysis framework. http://root.cern.ch/
[48] The RooFit packages, http://roofit.sourceforge.net/
[49] Akeroyd A G, CHEN C H. Phys. Rev. D, 2007,75: 075004; Akeroyd A G. Prog. Theor. Phys., 2004, 111: 295
[50] Rosner J L, Stone S. arXiv:0802.1043v2 [hep-ex]; Rosner J L, Stone S. Phys. Lett. B, 2008, 667:1
[51] Ikado K et al. (Belle Collaboration). Phys. Rev. Lett., 2006, 97: 251802
[52] Aubert B et al. (BaBar Collaboration). arXiv:0705.1820; Aubert B et al. (BaBar Collaboration). Phys. Rev. D, 2007,76: 052002
[53] YAO W M et al. (Partcle Data Group). J. Phys. G, 2006, 33: 1
[54] Artuso M et al. (CLEO Collaboration). Phys. Rev. Lett., 2005,95: 251801
[55] Artuso M et al. (CLEO Collaboration). Phys. Rev. Lett., 2007, 99: 071802
[56] Ecklund K M et al. (CLEO Collaboration). arXiv:0712.1175, 2007
[57] Aubert B et al. (BABAR Collaboration). Phys. Rev. Lett., 2007,98: 141801
[58] Abe K et al. (Belle Collaboration). arXiv:0709.1340, 2007
[59] Follana E et al. (HPQCD and UKQCD Collaboration). arXiv:0706.1726,2007
[60] Aubin C et al. (MILC Collaboration). Phys. Rev. Lett., 2005, 95: 122002
[61] Ali Khan A et al. (QCDSF Collaboration). Phys. Lett. B, 2007, 652: 150
[62] Chiu T W et al. Phys. Lett. B, 2005, 624: 31
[63] Lellouch L, LIN C J. Phys. Rev. D, 2001, 64: 094501
[64] Dobrescu B A, Kronfeld A S. arXiv:0803.0512 [hep-ph]
[65] LI H B. Nucl. Phys. B, 2006, Proc. Suppl. 162: 312
[66] Poling P. Invited Talk at 4th Flavor Physics and CP Violation Conference (FPCP 2006). Vancouver, British Columbia, Canada, 9-12 Apr 2006; In the Proceedings of 4th Flavor Physics and CP Violation Conference (FPCP 2006). Vancouver, British Columbia, Canada, 9-12 Apr 2006, hep-ex/0606016
[67] Asner D M. Proceedings of the CHARM2007 Workshop. Ithaca, NY, Auguest 5-8, 2007. arXiv:0711.3044
[68] Pedlar T K et al. (CLEO Collaboration). Phys. Rev. D, 2007, 76: 072002
[69] HE Q et al. (CLEO Collaboration). Phys. Rev. Lett., 2005,95: 121801; 2006,96: 199903
[70] Burdman G, Goldman T, Wyler D. Phys. Rev. D, 1995,51: 111
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