arXiv subjects

Dan Claes

Publications and source records attributed to Dan Claes.

3 recordsLinked to original sources

arXiv2004

Search for Pair Production of Light Scalar Top Quarks in p-pbar Collisions at sqrt{s}=1.8 TeV

Using 85.2 +/- 3.6 pb^-1 of p-pbar collisions collected at sqrt(s)=1.8 TeV with the D0 detector at Fermilab's Tevatron Collider, we present the results of a search for direct pair production of scalar top quarks ~t, the supersymmetric partners of the top quark. We examined events containing two or more jets and missing transverse energy, the signature of light scalar top quark decays to charm quarks and neutralinos. After selections, we observe 27 events while expecting 31.1 +/- 6.4 events from known standard model processes. Comparing these results to next-to-leading-order production cross sections, we exclude a significant region of ~t and neutralino phase space. In particular, we exclude the ~t mass m_~t < 122 GeV/c^2 for a neutralino mass of 45 GeV/c^2.

hep-ex↗

arXiv2003

LabView Interface for School-Network DAQ Card

A low-cost DAQ card has been developed for school-network cosmic ray detector projects, providing digitized data from photomultiplier tubes via a standard serial interface. To facilitate analysis of these data and to provide students with a starting point for custom readout systems, a model interface has been developed using the National Instruments LabVIEW(R) system. This user-friendly interface allows one to initialize the trigger coincidence conditions for data-taking runs and to monitor incoming or pre-recorded data sets with updating singles- and coincidence-rate plots and other user-selectable histograms.

physics.ins-det↗

arXiv2003

Low-Cost Data Acquisition Card for School-Network Cosmic Ray Detectors

The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln and the Washington Area Large-scale Time coincidence Array (WALTA) at University of Washington/Seattle are among several outreach projects siting cosmic-ray detectors at local high schools in cities around North America, to study the origins and interactions of high-energy cosmic rays. In a collaboration between QuarkNet, the outreach program based at Fermilab, CROP, and WALTA, a low-cost data acquisition electronics card has been developed to collect and synchronize the data from each detector site. The cost for each card is under US$500 for parts, functionally replacing much more expensive electronics crates and modules at each high school site. The card has 4 analog discriminator inputs for photo-multiplier tube signals, a 4-channel Time-to-Digital converter for local coincidence and time-over-threshold measurements at 0.75 ns resolution, programmable trigger logic via a CPLD and microcontroller, and a built-in low-cost GPS receiver/antenna module (via external cable) to provide event trigger time stamps at better than 100 ns accuracy. Temperature sensors and a barometer are also integrated to record environmental data along with the counter data. The card connects to any PC or laptop via a standard RS-232 serial port for data output and control. The microcontroller and CPLD are field programmable and therefore make the card functionality flexible and easy to upgrade.

physics.ins-det↗