Providing efficient access to more than 300TB of experiment data is the responsibility of the BaBar^1 Databases Group.Unlike generic tools,The Event Browser presents users with an abstraction of the BaBar data model.M...Providing efficient access to more than 300TB of experiment data is the responsibility of the BaBar^1 Databases Group.Unlike generic tools,The Event Browser presents users with an abstraction of the BaBar data model.Multithreaded CORBA^2 servers perform database operations using small transactions in an effort to avoid lock contention issues and provide adequate response times.The GUI client is implemented in Java and can be easily deployed throughout the community in the form of a web applet.The browser allows users to examine collections of related physics events and identify associations between the collections and the physical files in which they reside,helping administrators distribute data to other sites worldwide,This paper discusses the various aspects of the Event Browser including requirements,design challenges and key features of the current implementation.展开更多
The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the expe...The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year.However,with increased luminosity and changes in the physics requirements,these requirements have increased significantly for the current running period and will again increase in the future.New capabilities in the underlying ODBMS product,in particular those of multiple federation and read-only database support,have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime.Other optimizations,including the increased use of thghtly coupled CORBA servers and an improved awareness of space inefficiencies,are also playing a part in meeting the new scaling requirements.We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment.展开更多
In order to face the expected increase in statistics between now and 2005,the Babar experiment at SLAC is evolving its computing model toward a distributed multitier system.It is foreseen that data will be spread amon...In order to face the expected increase in statistics between now and 2005,the Babar experiment at SLAC is evolving its computing model toward a distributed multitier system.It is foreseen that data will be spread among Tier-A centers and deleted from the SLAC center,A unifrom computing enviromment is being deployed in the centers,the network bandwidth is continuously increased and data distribution tools has been designed in order to reach a transfer rate of -100 TB of data per year,In parallel,smaller Tier-B and C sites receive subsets of data,presently in Kanga-Root[1] format and later in Objectivity[2] format,GRID tools will be used for remote job submission.展开更多
The BaBer experiment stores its data in an Object oriented federated database supplied by Objectivity/DB(tm),this database is surrently 350TB in size and is expected to increase considerably as the experiment matures....The BaBer experiment stores its data in an Object oriented federated database supplied by Objectivity/DB(tm),this database is surrently 350TB in size and is expected to increase considerably as the experiment matures.Management of this database requires careful planning and specialized tools in order to make the data available to physicists in an efficient and timely manner,We discuss the operational issues and management tools that were developed during the previous run to deal with this vast quantity of data at SLAC.展开更多
The BaBar Experiment collected around 20 TB of data during its first 6 months of running.Now,after 18 months,data size exceeds 300 TB,and according to prognosis,it is a small fraction of the size of data coming in the...The BaBar Experiment collected around 20 TB of data during its first 6 months of running.Now,after 18 months,data size exceeds 300 TB,and according to prognosis,it is a small fraction of the size of data coming in the next few months,In order to keep up with the data significant effort was put into tuning the database system,It led to great performance improvements,as well as to inevitable system expansion-450 simultaneous processing nodes alone used for data reconstruction.It is believed,that further growth beyond 600 nodes will happen soon.In such an environment,many complex operations are executed simultaneously on hundreds of machines,putting a huge load on data servers and increasing network traffic Introducing two CORBA servers halved startup time,and dramatically offloaded database servers:data servers as well as lock servers The paper describes details of design and implementation of two servers recently in troduced in the Babar system:conditions OID server and Clustering Server,The first experience of using these servers is discussed.A discussion on a Collection Server for data analysis,currently being designed is included.展开更多
The BaBar data acquisition system(DAQ)transports data from the detector front end eletronics to short term disk storage.A monitoring application(VMON)has been developed to monitor the one hundred and ninety computers ...The BaBar data acquisition system(DAQ)transports data from the detector front end eletronics to short term disk storage.A monitoring application(VMON)has been developed to monitor the one hundred and ninety computers in the dataflow system.Performance information for each CPU is collected and multicast across the existing data transport network.The packets are currently collected by a single UNIX workstation and archived.A ROOT based GUI provides control and displays the DAQ performance in real time.The same GUI is reused to recover archived VMON data,VMON has been deployed and constantly monitors the BaBar dataflow system.It has been used for diagnostics and provides input to models projecting future performance.The application has no measurable impact on data taking ,responds instantaneously on the human timescale to requests for information display,and uses only 3% of a 300MHz Sun Ultra5 CPU.展开更多
BABAR[1] uses two formats for its data:Objectivity database and ROOT[1] files.This poster concerns the distribution of the latter-for Objectivity data see [3].The BABAR analysis data is stored in ROOT files-one per ph...BABAR[1] uses two formats for its data:Objectivity database and ROOT[1] files.This poster concerns the distribution of the latter-for Objectivity data see [3].The BABAR analysis data is stored in ROOT files-one per physics run and analysis selection channel-maintained in a large directory tree,Currently BABAR has more than 4.5 TBytes in 200,000 ROOT files.This data is (mostly)produced at SLAC,but is required for analysis at universities and research centres throughout the US and Europe.Two basic problems confront us when we seek to import bulk data from SLAC to an institute's local storage via the network.We must determine which files must be imported (depending on the local site requirements and which files have already been imported),and we must make the optimum use of the network when transferring the data,Basic ftp-like tools(ftp,scp,etc)do not attempt to solve the first problem.More sophisticated tools like rsync[4],the widely-used mirror/synchronisation program,compare local and remote file systems,checking for changes(based on file date,size and,if desired,an elaborate checksum)in order to only copy new or modified files,However rsync allows for only limited file selection.Also when,as in BABAR,an extremely large directory structure must be scanned,rsync can take several hours just to determine which files need to be copied.Although rsync(and scp)provides on -the=fly compression,it does not allow us to optimise the network transfer by using multiple streams,abjusting the TCP window size or separating encrypted authentication from unencrypted data channels.展开更多
We perform an analysis of all existing experimental data on the pion-photon transition form factor （TFF）. In the calculation, we include the next-to-leading order correction to the valence-quark contribution and est...We perform an analysis of all existing experimental data on the pion-photon transition form factor （TFF）. In the calculation, we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF＇s limiting behavior at both Q^2→0 and Q^2→∞. At present, the pion distribution amplitude （DA） is not definitely determined, it is helpful to have a pion DA model that can mimic all the behaviors suggested in the literature. For the purpose, we adopt the conventional model for pion wavefunction/DA whose broadness is dominantly controlled by a single parameter B. We fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within small Q^2 region （Q^2≤15 GeV^2）, where all the data are consistent with each other. The pion-photon TFF is then extrapolated into a larger Q^2 region. It is found that we still need more data at a large Q^2 region in order to determine the precise value of B, and we hope that the definite behavior of pion DA can be concluded finally by the consistent data in the coming future.展开更多
Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass （c.m.） energy, obtained via initial-state radiation （ISR） with the BABAR detector, are presented. The cross sections for many hadronic process...Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass （c.m.） energy, obtained via initial-state radiation （ISR） with the BABAR detector, are presented. The cross sections for many hadronic processes have been measured from the production threshold to 4-5 GeV of the e^＋e^- c.m. energy. The obtained data allow to study a number of intermediate states and determine the parameters of known resonances and their branching fractions. The exclusive cross section for some number of hadronic sub-processes are presented.展开更多
We present recent results from BABAR experiment for D^0-D^0mixing measurements. Mixing parameters can be measured in different ways using different D^ decay modes, here we discuss the most sensitive analyses such as ...We present recent results from BABAR experiment for D^0-D^0mixing measurements. Mixing parameters can be measured in different ways using different D^ decay modes, here we discuss the most sensitive analyses such as D^0→ K^＋π^- where we had the first evidence of charm mixing, the measurement of the ratio of lifetimes of the decays D^0→ K^K^ and D^0→π^＋π^- relative to D^0→ K^-π^＋, the time dependent Dalitz plot analysis of D^0→K^＋π^-π^0. New limits on CP-violating time-integrated asymmetries in Do→ K^＋K^- and D^0→π^＋π^- are also discussed. The analyses presented are based on 384 fb^-1 data collected with the BABAR detector at the PEP-II asymmetric B Factory.展开更多
We present a precise BABAR measurement on the cross section of the process e^＋e^- →π^＋π^-（γ） from threshold to an energy of 3 GeV with the initial state radiation （ISR） technique, using 232 fb^-1 of data col...We present a precise BABAR measurement on the cross section of the process e^＋e^- →π^＋π^-（γ） from threshold to an energy of 3 GeV with the initial state radiation （ISR） technique, using 232 fb^-1 of data collected with the BABAR detector at e^＋e^- center-of-mass energies near 10.58 GeV. The ISR luminosity is determined from a study of the leptonic process e^＋e^- →μ^＋μ^-γ（γ）. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the ππ cross section measured from threshold to 1.8 GeV is （514.1± 2.2（stat） ± 3.1（syst）） × 10^-10.展开更多
This paper intends to shortly summarize the recent results on Spectroscopy, published from the BABAR Collaboration. The BABAR experiment is a B-factory, at SLAC, where asymmetric energy beams of electron-positron are ...This paper intends to shortly summarize the recent results on Spectroscopy, published from the BABAR Collaboration. The BABAR experiment is a B-factory, at SLAC, where asymmetric energy beams of electron-positron are accelerated and collide at the energy in the center of mass of T（4S）. In 9 years of data taking, BABAR had collected 433 fb^-1 equivalent luminosity on-peak-data at the T（4S） energy, 30 fb^-1 data at the T（3S） energy, 15 fb^-1 data at the T（2S） energy, and a scan around T（4S） was done, collecting 25 pb^-1 every 5 MeV. Thanks to the high luminosity achieved, it is possible to perform high precision measurements, and spectroscopy studies. An update on the measurement of the state X（3872） will be given, as final result published by using the whole dataset available. Then, a new preliminary Y（4260） measurement is reported, and the study of the invariant mass J/ψπ^＋π^- in ISR events is shown, where no evidence of the state Y（4050） is highlighted. As conclusion, the results on the angular distribution analysis performed on the state Z（4430） are reported.展开更多
BABAR has measured with unprecedented accuracy the e^＋e^- → pp and e^＋e^- →∧∧ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution...BABAR has measured with unprecedented accuracy the e^＋e^- → pp and e^＋e^- →∧∧ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution and full angular acceptance, even exactly at threshold. A peculiar feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, this phenomenon is expected according to the Coulomb interaction between the outgoing baryon and antibaryon. Once this Coulomb enhancement factor is taken into account, the striking result is achieved that the proton form factor at threshold is ｜GP（4Mp^2）｜ = 1, that is what is expected for pointlike fermion pairs, in spite of the proton structure. However a Coulomb enhancement factor is not expected for neutral fermions, likely in contradiction with the BABAR data. Qualitatively this behaviour is consistent with Coulomb interactions at the valence quark level.展开更多
文摘Providing efficient access to more than 300TB of experiment data is the responsibility of the BaBar^1 Databases Group.Unlike generic tools,The Event Browser presents users with an abstraction of the BaBar data model.Multithreaded CORBA^2 servers perform database operations using small transactions in an effort to avoid lock contention issues and provide adequate response times.The GUI client is implemented in Java and can be easily deployed throughout the community in the form of a web applet.The browser allows users to examine collections of related physics events and identify associations between the collections and the physical files in which they reside,helping administrators distribute data to other sites worldwide,This paper discusses the various aspects of the Event Browser including requirements,design challenges and key features of the current implementation.
文摘The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year.However,with increased luminosity and changes in the physics requirements,these requirements have increased significantly for the current running period and will again increase in the future.New capabilities in the underlying ODBMS product,in particular those of multiple federation and read-only database support,have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime.Other optimizations,including the increased use of thghtly coupled CORBA servers and an improved awareness of space inefficiencies,are also playing a part in meeting the new scaling requirements.We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment.
文摘In order to face the expected increase in statistics between now and 2005,the Babar experiment at SLAC is evolving its computing model toward a distributed multitier system.It is foreseen that data will be spread among Tier-A centers and deleted from the SLAC center,A unifrom computing enviromment is being deployed in the centers,the network bandwidth is continuously increased and data distribution tools has been designed in order to reach a transfer rate of -100 TB of data per year,In parallel,smaller Tier-B and C sites receive subsets of data,presently in Kanga-Root[1] format and later in Objectivity[2] format,GRID tools will be used for remote job submission.
文摘The BaBer experiment stores its data in an Object oriented federated database supplied by Objectivity/DB(tm),this database is surrently 350TB in size and is expected to increase considerably as the experiment matures.Management of this database requires careful planning and specialized tools in order to make the data available to physicists in an efficient and timely manner,We discuss the operational issues and management tools that were developed during the previous run to deal with this vast quantity of data at SLAC.
文摘The BaBar Experiment collected around 20 TB of data during its first 6 months of running.Now,after 18 months,data size exceeds 300 TB,and according to prognosis,it is a small fraction of the size of data coming in the next few months,In order to keep up with the data significant effort was put into tuning the database system,It led to great performance improvements,as well as to inevitable system expansion-450 simultaneous processing nodes alone used for data reconstruction.It is believed,that further growth beyond 600 nodes will happen soon.In such an environment,many complex operations are executed simultaneously on hundreds of machines,putting a huge load on data servers and increasing network traffic Introducing two CORBA servers halved startup time,and dramatically offloaded database servers:data servers as well as lock servers The paper describes details of design and implementation of two servers recently in troduced in the Babar system:conditions OID server and Clustering Server,The first experience of using these servers is discussed.A discussion on a Collection Server for data analysis,currently being designed is included.
文摘The BaBar data acquisition system(DAQ)transports data from the detector front end eletronics to short term disk storage.A monitoring application(VMON)has been developed to monitor the one hundred and ninety computers in the dataflow system.Performance information for each CPU is collected and multicast across the existing data transport network.The packets are currently collected by a single UNIX workstation and archived.A ROOT based GUI provides control and displays the DAQ performance in real time.The same GUI is reused to recover archived VMON data,VMON has been deployed and constantly monitors the BaBar dataflow system.It has been used for diagnostics and provides input to models projecting future performance.The application has no measurable impact on data taking ,responds instantaneously on the human timescale to requests for information display,and uses only 3% of a 300MHz Sun Ultra5 CPU.
文摘BABAR[1] uses two formats for its data:Objectivity database and ROOT[1] files.This poster concerns the distribution of the latter-for Objectivity data see [3].The BABAR analysis data is stored in ROOT files-one per physics run and analysis selection channel-maintained in a large directory tree,Currently BABAR has more than 4.5 TBytes in 200,000 ROOT files.This data is (mostly)produced at SLAC,but is required for analysis at universities and research centres throughout the US and Europe.Two basic problems confront us when we seek to import bulk data from SLAC to an institute's local storage via the network.We must determine which files must be imported (depending on the local site requirements and which files have already been imported),and we must make the optimum use of the network when transferring the data,Basic ftp-like tools(ftp,scp,etc)do not attempt to solve the first problem.More sophisticated tools like rsync[4],the widely-used mirror/synchronisation program,compare local and remote file systems,checking for changes(based on file date,size and,if desired,an elaborate checksum)in order to only copy new or modified files,However rsync allows for only limited file selection.Also when,as in BABAR,an extremely large directory structure must be scanned,rsync can take several hours just to determine which files need to be copied.Although rsync(and scp)provides on -the=fly compression,it does not allow us to optimise the network transfer by using multiple streams,abjusting the TCP window size or separating encrypted authentication from unencrypted data channels.
基金Supported by Natural Science Foundation of China(10975144,11075225)Program for New Century Excellent Talents in University(NCET-10-0882)Fundamental Research Funds for Central Universities(CQDXWL-2012-Z002)
文摘We perform an analysis of all existing experimental data on the pion-photon transition form factor （TFF）. In the calculation, we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF＇s limiting behavior at both Q^2→0 and Q^2→∞. At present, the pion distribution amplitude （DA） is not definitely determined, it is helpful to have a pion DA model that can mimic all the behaviors suggested in the literature. For the purpose, we adopt the conventional model for pion wavefunction/DA whose broadness is dominantly controlled by a single parameter B. We fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within small Q^2 region （Q^2≤15 GeV^2）, where all the data are consistent with each other. The pion-photon TFF is then extrapolated into a larger Q^2 region. It is found that we still need more data at a large Q^2 region in order to determine the precise value of B, and we hope that the definite behavior of pion DA can be concluded finally by the consistent data in the coming future.
基金Supported by Russian Foundation of Basic Research (09-02-08413-3)
文摘Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass （c.m.） energy, obtained via initial-state radiation （ISR） with the BABAR detector, are presented. The cross sections for many hadronic processes have been measured from the production threshold to 4-5 GeV of the e^＋e^- c.m. energy. The obtained data allow to study a number of intermediate states and determine the parameters of known resonances and their branching fractions. The exclusive cross section for some number of hadronic sub-processes are presented.
基金Universitàdi Pisa and INFN. Also Supported by U.S.Department of Energy and SLAC,Stanford University
文摘We present recent results from BABAR experiment for D^0-D^0mixing measurements. Mixing parameters can be measured in different ways using different D^ decay modes, here we discuss the most sensitive analyses such as D^0→ K^＋π^- where we had the first evidence of charm mixing, the measurement of the ratio of lifetimes of the decays D^0→ K^K^ and D^0→π^＋π^- relative to D^0→ K^-π^＋, the time dependent Dalitz plot analysis of D^0→K^＋π^-π^0. New limits on CP-violating time-integrated asymmetries in Do→ K^＋K^- and D^0→π^＋π^- are also discussed. The analyses presented are based on 384 fb^-1 data collected with the BABAR detector at the PEP-II asymmetric B Factory.
文摘We present a precise BABAR measurement on the cross section of the process e^＋e^- →π^＋π^-（γ） from threshold to an energy of 3 GeV with the initial state radiation （ISR） technique, using 232 fb^-1 of data collected with the BABAR detector at e^＋e^- center-of-mass energies near 10.58 GeV. The ISR luminosity is determined from a study of the leptonic process e^＋e^- →μ^＋μ^-γ（γ）. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the ππ cross section measured from threshold to 1.8 GeV is （514.1± 2.2（stat） ± 3.1（syst）） × 10^-10.
基金Supported by the US Department of Energy and National Science Foundationthe Natural Sciences and Engineering Research Council (Canada)+7 种基金the Commissariat a l'Energie Atomique and Institut National de Physique Nucleaire et de Physique des Particules (France)the Bundesministerium fur Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany)the Istituto Nazionale di Fisica Nucleare (Italy)the Foundation for Fundamental Research on Matter (The Netherlands)the Research Council of Norway,the Ministry of Education and Science of the Russian Federation,Ministerio de Educacion y Ciencia (Spain)the Science and Technology Facilities Council (United Kingdom)Individuals have received support from the Marie-Curie IEF program (European Union)the A.P.Sloan Foundation
文摘This paper intends to shortly summarize the recent results on Spectroscopy, published from the BABAR Collaboration. The BABAR experiment is a B-factory, at SLAC, where asymmetric energy beams of electron-positron are accelerated and collide at the energy in the center of mass of T（4S）. In 9 years of data taking, BABAR had collected 433 fb^-1 equivalent luminosity on-peak-data at the T（4S） energy, 30 fb^-1 data at the T（3S） energy, 15 fb^-1 data at the T（2S） energy, and a scan around T（4S） was done, collecting 25 pb^-1 every 5 MeV. Thanks to the high luminosity achieved, it is possible to perform high precision measurements, and spectroscopy studies. An update on the measurement of the state X（3872） will be given, as final result published by using the whole dataset available. Then, a new preliminary Y（4260） measurement is reported, and the study of the invariant mass J/ψπ^＋π^- in ISR events is shown, where no evidence of the state Y（4050） is highlighted. As conclusion, the results on the angular distribution analysis performed on the state Z（4430） are reported.
文摘BABAR has measured with unprecedented accuracy the e^＋e^- → pp and e^＋e^- →∧∧ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution and full angular acceptance, even exactly at threshold. A peculiar feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, this phenomenon is expected according to the Coulomb interaction between the outgoing baryon and antibaryon. Once this Coulomb enhancement factor is taken into account, the striking result is achieved that the proton form factor at threshold is ｜GP（4Mp^2）｜ = 1, that is what is expected for pointlike fermion pairs, in spite of the proton structure. However a Coulomb enhancement factor is not expected for neutral fermions, likely in contradiction with the BABAR data. Qualitatively this behaviour is consistent with Coulomb interactions at the valence quark level.
基金Supported by DOE and NSF(USA)NSERC(Canada)+8 种基金CEA and CNRS-IN2P3(France)BMBF and DFG(Germany)INFN(Italy)FOM(The Netherlands)NFR(Norway)MES(Russia)MICIIN(Spain)STFC(United Kingdom)Individuals have received support from the DFG(Germany)
