## Publications Page

### FOCUS Papers

A measurement of lifetime differences in the neutral D-meson system Phys. Lett. B485:62 Using a high statistics sample of photoproduced charm particles from the FOCUS experiment at Fermilab, we compare the lifetimes of neutral D mesons decaying via K-pi+ and K-K+ to measure the lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of D0-D0bar mixing. We measure Ycp = 3.42 pm 1.39 pm 0.74 %. Postscript
Measurements of the Sigma-c-0 and Sigma-c-++ Mass Splittings Phys. Lett. B488:218 Using a high statistics sample of photoproduced charmed particles from the FOCUS experiment at Fermilab (FNAL-E831), we measure the mass splittings of the charmed baryons Sigma_c^0 and Sigma_c^{++}. We find M(Sigma_c^0 - Lambda_c^+) = 167.38 +/- 0.21 +/- 0.13 MeV/c^2 and M(Sigma_c^++ - Lambda_c^+) = 167.35 +/- 0.19 +/- 0.12 MeV/c^2 with samples of 362 +/- 36 and 461 +/- 39 events, respectively. We measure the isospin mass splitting M(Sigma_c^++ - Sigma_c^0) to be -0.03 +/- 0.28 +/- 0.11 Mev/c^2. The first errors are statistical and the second are systematic. Postscript
Search for CP Violation in D0 and D+ Decays Phys. Lett. B491:232 A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/- 0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) = +0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements. hep-ex archive
A Study of the Decay D0->K+ pi- Phys. Rev. Lett. 86:2955 Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay $D^0\to K^+\pi^-$ with a signal yield of $149\pm31$ events compared to a similarly cut sample consisting of $36760 \pm 195$ $D^0\to K^-\pi^+$ events. We use the observed ratio of $D^0\to K^+\pi^-$ to $D^0\to K^-\pi^+$ $(0.404\pm 0.085\pm 0.025)%$ to obtain a relationship between the $D^0$ mixing and doubly Cabibbo suppressed decay parameters. hep-ex archive
Measurement of the relative branching ratio BR(XI_c+ ->pK-pi+)/BR(XI_c+ -> XI- pi+ pi+) Phys. Lett. B512:277 We report the observation of the Cabibbo suppressed decay XI_c+ -> p K- pi+ using data collected with the FOCUS spectrometer during the 1996-97 Fermilab fixed target run. We find a XI_c+ signal peak of 202 +/- 35 events. We have measured the relative branching ratios BR(XI_c+ ->pK-pi+)/BR(XI_c+->XI- pi+ pi+) = 0.234 +/- 0.047 +/- 0.022 and BR(XI_c+ -> p bar(K*)(892)0)/BR(XI_c+ ->pK-pi+)=0.54+/-0.09+/-0.05. hep-ex archive

### FOCUS Conference Proceedings

FOCUS Conferences proceedings are available from the Conference Talks and Proceedings database.