arXiv subjects

David A. Sanders

Publications and source records attributed to David A. Sanders.

5 recordsLinked to original sources

arXiv2009

A Cherenkov Radiation Detector with High Density Aerogels

We have designed a threshold Cherenkov detector at the Rutherford-Appleton Laboratory to identify muons with momenta between 230 and 350 MeV/c. We investigated the properties of three aerogels for the design. The nominal indexes of refraction were n = 1.03, 1.07, 1.12, respectively. Two of the samples are of high density aerogel not commonly used for Cherenkov light detection. We present results of an examination of some optical properties of the aerogel samples and present basic test beam results.

physics.ins-det↗

arXiv2005

Simulation of Heavily Irradiated Silicon Pixel Sensors and Comparison with Test Beam Measurements

Charge collection measurements performed on heavily irradiated p-spray DOFZ pixel sensors with a grazing angle hadron beam provide a sensitive determination of the electric field within the detectors. The data are compared with a complete charge transport simulation of the sensor which includes signal trapping and charge induction effects. A linearly varying electric field based upon the standard picture of a constant type-inverted effective doping density is inconsistent with the data. A two-trap double junction model implemented in the ISE TCAD software can be tuned to produce a doubly-peaked electric field which describes the data reasonably well. The modeled field differs somewhat from previous determinations based upon the transient current technique. The model can also account for the level of charge trapping observed in the data.

physics.ins-det↗

arXiv2001

Rare and Forbidden Decays of D Mesons

We summarize the results of two recent searches for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examined D+ and Ds pi,l,l and K,l,l decay modes and the D0 dilepton decay modes containing either l+,l-, a rho0, K*0, or phi vector meson, or a non-resonant pi,pi, K,pi, or K,K pair of pseudoscalar mesons. No evidence for any of these decays was found. Therefore, we presented branching-fraction upper limits at 90% confidence level for the 51 decay modes examined. Twenty-six of these modes had no previously reported limits, and eighteen of the remainder were reported with significant improvements over previously published results.

hep-ex↗

arXiv2000

Review of Recent Searches for Rare and Forbidden Dilepton Decays of Charmed Mesons

I briefly review the results of recent searches for flavor-changing neutral current and lepton-flavor and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. The primary focus is the results from Fermilab charm hadroproduction experiment E791. E791 examined 24 pi,l,l and K,l,l decay modes of D+ and Ds and l+l- decay modes of D0. Limits presented by E791 for 22 rare and forbidden dilepton decays of D mesons were more stringent than those obtained from previous searches, or else were the first reported.

hep-ex↗

arXiv1999

Recent Results from Fermilab Charm Experiment E791

We report the results of some recent E791 charm analyses. They include: 1) a search for rare and forbidden decays, 2) measurements of form factors for D+ --> K*,l,nu and Ds --> phi,l,nu, and 3) Ds and D0 lifetime measurements including the lifetime difference between D0-->Kpi and D0-->KK. The latter is the first direct search for a possible lifetime difference that could contribute to D0-D0bar mixing.

hep-ex↗