arXiv subjects

The FOCUS collaboration

Publications and source records attributed to The FOCUS collaboration.

5 recordsLinked to original sources

arXiv2006

A Non-parametric Approach to Measuring the \kpi{} Amplitudes in \dpkkpi{} Decay

Using a large sample of \dpkkpi{} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the \kpi{} amplitudes in \dpkkpi{} decay. The technique is similar to the technique used for our non-parametric measurements of the \krzmndk{} form factors. Although these results are in rough agreement with those of E687, we observe a wider S-wave contribution for the \ksw{} contribution than the standard, PDG \cite{pdg} Breit-Wigner parameterization. We have some weaker evidence for the existence of a new, D-wave component at low values of the $K^- π^+$ mass.

hep-ex↗

arXiv2006

New Measurement of BR(D+ ->Rho0 Mu+ Nu) / BR(D+ ->K*0 Mu+ Nu) Branching Ratio

Using data collected by the FOCUS experiment at Fermilab, we present a new measurement of the charm semileptonic branching ratio BR(D+ -> rho0 mu+ nu)/BR(D+ -> K*0 mu+ nu). From a sample of 320+-44 and 11372+-161 D+ -> rho0 mu+ nu and D+ -> K*0 mu+ nu events respectively, we find BR(D+ -> rho0 mu+ nu)/BR(D+ -> K*0 mu+ nu)=0.041+-0.006(stat)+-0.004(syst).

hep-ex↗

arXiv2002

New measurements of the D0 and D+ lifetimes

A high statistics sample of photoproduced charm particles from the FOCUS(E831) experiment at Fermilab has been used to measure the D0 and D+ lifetimes. Using about 210000 D0 and 110000 D+ events we obtained the following values: 409.6 +/- 1.1 (statistical) +/- 1.5 (systematic) fs for D0 and 1039.4 +/- 4.3 (statistical) +/- 7.0 (systematic) fs for D+.

hep-ex↗

arXiv2001

Measurement of the relative branching ratio BR(Ξ_c^+ \to p^+ K^-π^+)\BR(Ξ_c^+ \to Ξ^- π^+ π^+)

We report the observation of the Cabibbo suppressed decay Ξ_c^+ \to p K^-π^+ using data collected with the FOCUS spectrometer during the 1996--97 Fermilab fixed target run. We find a Ξ_c^+ signal peak of 202\pm35 events. We have measured the relative branching ratios BR(Ξ^+_c\to p K^-π^+)/BR(Ξ^+_c\toΞ^-π^+π^+)= 0.234 \pm 0.047 \pm 0.022 and BR(Ξ^+_c\to p \bar{K}^*(892)^0)/BR(Ξ^+_c\to p K^-π^+)= 0.54 \pm 0.09 \pm 0.05 .

hep-ex↗

arXiv2000

Search for CP violation in D0 and D+ decays

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↗