123343445
Status of the g-2 experiment at BNL
The muon g-2 experiment at Brookhaven has successfully completed two exploratory runs using pion injection and direct muon injection for checkout and initial data taking. The main components of the experiment, which include the pion beam line, the superconducting storage ring and inflector magnets, the muon kicker and the lead-scintillating fiber calorimeters have been satisfactorily commissioned. First results on the anomalous magnetic moment of the positive muon from pion injection are in good agreement with previous experimental results for a(mu+) and a(mu-) from CERN and of comparable accuracy (13 ppm). Analysis of the 1998 muon injection run is in progress and expected to improve the precision to about 4 ppm. A first production run is scheduled for January 1999 with the goal of reaching the 1 ppm error level.
37689024
Lowest order hadronic contribution to the muon g-2 value with systematic error correlations.
We have performed a new evaluation of the hadronic contribution to {ital a}{sub {mu}}=({ital g}{minus}2)/2 of the muon with explicit correlations of systematic errors among the experimental data on {sigma}({ital e}{sup +}{ital e}{sup {minus}}{r_arrow}hadrons). Our result for the lowest order hadronic vacuum polarization contribution is {ital a}{sub {mu}}{sup had}=702.6(7.8)(14.0){times}10{sup {minus}10} where the first error is statistical and the second is systematic. The total systematic error contributions from below and above {radical}{ital s}=1.4 GeV are (13.1){times}10{sup {minus}10} and (5.1){times}10{sup {minus}10}, respectively, and are hence dominated by the low energy region. Therefore, new measurements on {sigma}({ital e}{sup +}{ital e}{sup {minus}}{r_arrow}hadrons) below 1.4 GeV can significantly reduce the total error on {ital a}{sub {mu}}{sup had}. In particular, the effect on the total errors of new hypothetical data with 3{percent} statistical and 0.5{endash}1.0{percent} systematic errors is presented. {copyright} {ital 1996 The American Physical Society.}
118611843
Measurement of three pion production in electron-positron annihilations for the hadronic contribution to the anomalous magnetic moment of the muon
119488847
Scintillating fiber hodoscope for a bremsstrahlung luminosity monitor at an electron–positron collider
The performance of a scintillating fiber (2 mm diameter) position sensitive detector (4.8×4.8 cm2 active area) for the single bremsstrahlung luminosity monitor at the VEPP‐2M electron‐positron collider in Novosibirsk, Russia is described. Custom electronics is triggered by coincident hits in the Y and Y planes of 24 fibers each, and reduces 64 photomultiplier signals to a 10‐bit (X,Y) address. Hits are accumulated (10 kHz) in memory and display (few Hz) the VEPP‐2M collision vertex. Fitting the strongly peaked distribution (∼3–4 mm at 1.6 m from the collision vertex of VEPP‐2M) to the expected QED angular distribution yields a background in agreement with an independent determination of the VEPP‐2M luminosity.
118033057
A Comparison of High Transverse Momentum Direct Photon and Neutral Pion Events in Negative Pion and Proton - Nucleus Collisions at 31.5-GeV Center-of-Mass Energy
119368956
Mu2e: a Muon to Electron Conversion Experiment at Fermilab
Abstract We present the status of Mu2e, a proposed experiment to measure the rate of muon to electron conversion in the field of a nucleus. The Mu2e experiment will be hosted by Fermilab at a new muon campus, using a new beamline to deliver protons to the muon generation target. Mu2e will use a series of three solenoids to collect, transport, stop, and analyze the muons produced when the 8 GeV pulsed proton beam from the booster hits the tungsten production target. The 200 nsec wide proton pulse is designed to have a ratio of out-of-time to in-time protons better than 10 − 10 , insuring a measurement time window of approximately 1 microsecond essentially free from beam pion background. A precision, low-mass straw tube tracker will measure electron momenta with a precision of 1/1000, allowing clean separation of the conversion signal from Decay In Orbit electrons, the principle experimental background. Extensive coverage of multi-layer scintillation counters will detect 99.99% of the cosmic muons which could generate fake signals. A crystal calorimeter will provide particle ID to further reduce backgrounds. Detailed simulations show a 3-year run with 7.56 × 10 17 stopped muons will allow a Single Event Sensitivity of 2 × 10 − 17 , allowing an estimated 90% confidence level sensitivity to R μ e of 6 × 10 − 17 , a four-orders of magnitude improvement over existing limits. The Mu2e schedule is technically limited, with commissioning beginning in 2019. Mu2e may also run at Project X with 10× higher luminosity using either an aluminum or titanium target after minimal upgrades.
38971102
CDB - Distributed Conditions Database of BaBar Experiment
This document presents CDB – Distributed Conditions Database of the BaBar Experiment [1]. CDB is the second major iteration of the database deployed in BaBar for production use as of October 2002. It replaced the original version of the database [2] used through the first three years of the data taking. The new design and its implementation are aiming at performance and scalability limitations of the original database, as well as at emerging challenges of a distributed data production and analysis system [3] of the Experiment.
61201473
GLOBAL VDET PATTERN RECOGNITION FOR ALEPH
With the current reliance on high-precision vertex detectors to provide very accurate information about the primary and secondary vertices in an event, the accuracy and ee-ciency of the assignment of vertex detector hits to tracks has become crucial. This paper discusses new software written for ALEPH which attempts to make this assignment in a global manner using integer programming techniques.
62691127
Computing for the next generation flavour factories
The next generation of Super Flavor Factories, like SuperB and SuperKEKB, present significant computing challenges. Extrapolating the BaBar and Belle experience to the SuperB nominal luminosity of 1036 cm−2s−1, we estimate that the data size collected after a few years of operation is 200 PB and the amount of CPU required to process them of the order of 2000 KHep-Spec06. Already in the current phase of detector design, the amount of simulated events needed for estimating the impact on very rare benchmark channels is huge and has required the development of new simulation tools and the deployment of a worldwide production distributed system. With the collider is in operation, very large data set have to be managed and new technologies with potential large impact on the computational models, like the many core CPUs, need to be effectively exploited. In addition SuperB, like the LHC experiments, will have to make use of distributed computing resources accessible via the Grid infrastructures while providing an efficient and reliable data access model to its final users. To explore the key issues, a dedicated R&D program has been launched and is now in progress. A description of the R&D goals and the status of ongoing activities is presented.