Joann Quiñones

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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 D → Kπand KK to measure the lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of D − D̄ mixing. If the D → Kπ is an equal mixture of CP even(More)
We review genetic programming principles, their application to FOCUS data samples, and use the method to study the doubly Cabibbo suppressed decay D → Kπ+π− relative to its Cabibbo favored counterpart, D → Kππ. We find that this technique is able to improve upon more traditional analysis methods. To our knowledge, this is the first application of the(More)
A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+)(More)
A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+-->K(S)pi+ and D+-->K(S)K+. We have measured the following asymmetry parameters relative to D+-->K-pi+pi+: A(CP)(K(S)pi+) = (-1.6+/-1.5+/-0.9)%, A(CP)(K(S)K+) = (+6.9+/-6.0+/-1.5)%, and A(CP)(K(S)K+) =(More)
We describe the algorithm used to identify charged tracks in the fixed-target charmphotoproduction experiment FOCUS. We begin by describing the new algorithm and contrast this approach with that used in our preceding experiment—E687. We next illustrate the algorithm’s performance using physics signals. Finally we briefly describe some of the methods used to(More)
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 Σc and Σ ++ c . We find M(Σ 0 c − Λ + c ) = 167.38 ± 0.21 ± 0.13 MeV/c 2 and M(Σ c −Λ + c ) = 167.35±0.19±0.12 MeV/c 2 with samples of 362±36 and 461±39 events, respectively. We measure(More)
We have studied hadronic four-body decays of D(+) and D(+)(s) mesons with a K(S) in the final state using data recorded during the 1996-1997 fixed-target run of the Fermilab high energy photoproduction experiment FOCUS. We report a new branching ratio measurement of gamma(D(+)-->K(S)K-pi(+)pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0768+/-0.0041+/-0.0032.(More)
In this paper we present a measurement of the natural widths of Σc and Σ ++ c . Using data from the FOCUS experiment, we find Γ(Σc) = 1.55 +0.41 −0.37 ± 0.38 MeV/c 2 and Γ(Σ c ) = 2.05 +0.41 −0.38 ± 0.38 MeV/c . The first errors are statistical, the second systematic. These results are obtained with a sample of 913 Σc → Λ + c π − decays and 1110 Σ c → Λ + c(More)
Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode D0 → K−K−K+π+. From a sample of 143±19 fully reconstructedD0 → K−K−K+π+ events, we measure Γ(D0 → K−K−K+π+)/Γ(D0 → K−π−π+π+) = 0.00257 ± 0.00034(stat.) ± 0.00024(syst.). A coherent amplitude analysis has been(More)