119236409
Environmental dependence of the performance of resistive plate chambers
This paper reports on the performance of Resistive Plate Chambers (RPCs) as function of the gas flow rate through the chambers and of environmental conditions, such as atmospheric pressure, ambient temperature and air humidity. The chambers are read out by pads with an area of 1 × 1 cm2 and 1-bit resolution per pad (binary readout). The performance measures include the noise rate as well as the detection efficiency and pad multiplicity for cosmic rays. The measurements extended over a period of almost one year and are sensitive to possible long-term aging effects.
120352655
The ASTERIX spectrometer at LEAR
The ASTERIX spectrometer has been used to study the formation and the ground state of the pp atom and exclusive final states of pp annihilation at rest in a H2 gas target at NTP, using antiprotons from the Low Energy Antiproton Ring (LEAR) at CERN. The article describes the mechanical construction of the apparatus, the trigger logic, the chamber readout, and the data acquisition system. The detector calibration and the offline processing of the 55 million reconstructed events are illustrated. An overview is given about the new physics results obtained by the experiment.
173983707
Detecting High Mass H 0 A 0 Pairs at a 1 TeV Linear Collider
This note describes results from a study ofH0A0 associated production at a linear e+e− collider with √ s = 1.0 TeV. For the values of tanβ as well as the H0 and A0 masses considered here, the dominant decay mode is bb pairs. This fully hadronic final state has limited backgrounds at an e+e− collider, but at the LHC or VLHC it suffers extremely high backgrounds from standard QCD jet production. At an e+e− collider, the dominant background is tt production with fully hadronic t–quark decay in which the c–quarks fromW± decay are misidentified as b’s. Other backgrounds such as four–fermion production are negligible because of the signal is dominated by a four b final state. The results of this study are quite encouraging. Good signal–to–background was observed using event rates alone, and reconstructed Higgs mass distributions showed high–efficiency, low background regions. This note has four sections. The first is a description of the Monte Carlo generation and simulation. The second describes the analysis, including mass reconstruction and jet–flavor identification. The third presents the results, and the fourth discusses additional work to be done.
119211346
Hadron showers in a digital hadron calorimeter
A small prototype of a finely granulated digital hadron calorimeter with Resistive Plate Chambers as active elements was exposed to positive pions of 1–16 GeV energy from the Fermilab test beam. The event selection separates events with mostly non-interacting particles and events with hadronic showers which initiated in the front part of the calorimeter. The data are compared to a Monte Carlo simulation of the set-up. The paper concludes with predictions for the performance of an extended digital hadron calorimeter.
54177341
Measurement of the rate capability of Resistive Plate Chambers
This paper reports on detailed measurements of the performance of Resistive Plate Chambers in a proton beam with variable intensity. Short term effects, such as dead time, are studied using consecutive events. On larger time scales, for various beam intensities the chamber's efficiency is studied as a function of time within a spill of particles. The correlation between the efficiency of chambers placed in the same beam provides an indication of the lateral size of the observed effects. The measurements are compared to the predictions of a simple model based on the assumption that the resistive plates behave as pure resistors.
14888027
A precision synchrotron radiation detector using phosphorescent screens
A precision detector to measure synchrotron radiation beam positions is described. It has been designed and installed as part of the beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 mu m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in measuring SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. >
118032706
Excited charmed mesons
The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one.
119875628
Conference summary: 6th International conference on hyperons, charm, and beauty hadrons (BEACH04)
The 6th International Conference on Hyperons, Charm, and Beauty Hadrons (BEACH04) treated us to a wonderful array of new results. Here the author attempts to summarize the talks and discuss the conference highlights.
58032405
Distributed and/or grid-oriented approach to BTeV data analysis
Abstract The BTeV collaboration will record approximately 2 petabytes of raw data per year. It plans to analyze this data using the distributed resources of the collaboration as well as dedicated resources, primarily residing in the very large BTeV trigger farm, and resources accessible through the developing world-wide data grid. The data analysis system is being designed from the very start with this approach in mind. In particular, we plan a fully disk-based data storage system with multiple copies of the data distributed across the collaboration to provide redundancy and to optimize access. We will also position ourself to take maximum advantage of shared systems, as well as dedicated systems, at our collaborating institutions.
112436340
CHEP95 CONFERENCE SUMMARY
118563698
Hadron and photon production of heavy quarks
Recent results on the production dynamics of bottom from the Collider Detector Facility, E653, and E672 at Fermilab are reviewed and compared to previous results and theory. Agreement with theory is reasonable but the possible origins of the differences that do exist may lie in higher order corrections or possibly the shape of the gluon distribution. New results on the A‐dependence of charm are summarized. Recent results are converging towards an α parameter of 1, independent of xF. Results on inclusive charm production from Fermilab E769 and E653 and CERN WA82 are reviewed. Recent results on D−D correlations in photoproduction from E687 at Fermilab are reported. Many new results on charmed baryon states from CLEO, E687, ARGUS, and Serpukhov BIS‐2 are reviewed. This is an area where rapid progress is now occurring. Results on the D* branching fractions, Ds branching fractions, doubly Cabibbo suppressed decays, and the ratio D°→KK/D°→ππ are covered.