We apply a genetic programming technique to search for the doubly Cabibbo suppressed decays Λc+→pK+π− and Ds+→K+K+π−. We normalize these decays to their Cabibbo favored partners and find ...BR(Λc+→pK+π−)/BR(Λc+→pK−π+)=(0.05±0.26±0.02)% and BR(Ds+→K+K+π−)/BR(Ds+→K−K+π+)=(0.52±0.17±0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find <0.46 and <0.78%, respectively. This is the first successful use of genetic programming in a high energy physics data analysis.
We present an analysis of the decay D0→K+π− based on FOCUS data. From a sample of 234 signal events, we find a branching ratio of Γ(D0→K+π−)Γ(D0→K−π+)=(0.429−0.061+0.063±0.027)% under the assumptions ...of no mixing and no CP violation. Allowing for CP violation, we find a branching ratio of (0.429±0.063±0.028)% and a CP asymmetry of 0.18±0.14±0.04. The branching ratio for the case of mixing with no CP violation is (0.381−0.163+0.167±0.092)%. We also present limits on charm mixing.
Study of the D0→K+K−π+π− decay Link, J.M.; Yager, P.M.; Anjos, J.C. ...
Physics letters. B,
03/2005, Volume:
610, Issue:
3-4
Journal Article
Peer reviewed
Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the Cabibbo-suppressed decay mode D0→K+K−π+π−. We measure: ...Γ(D0→K+K−π+π−)/Γ(D0→K−π−π+π+)=0.0295±0.0011±0.0008. An amplitude analysis has been performed in order to determine the resonant substructure of this decay mode. The dominant components are the decays D0→K1(1270)+K−, D0→K1(1400)+K− and D0→ρ(770)0ϕ(1020).
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(+) decays represents a significant improvement over the present world average.
A study of D0→KS0KS0X decay channels Link, J.M.; Yager, P.M.; Anjos, J.C. ...
Physics letters. B,
02/2005, Volume:
607, Issue:
1-2
Journal Article
Peer reviewed
Using data from the FOCUS experiment (FNAL-E831), we report on the decay of D0 mesons into final states containing more than one KS0. We present evidence for two Cabibbo favored decay modes, ...D0→KS0KS0K−π+ and D0→KS0KS0K+π−, and measure their combined branching fraction relative to D0→K¯0π+π− to be Γ(D0→KS0KS0K±π∓)Γ(D0→K¯0π+π−)=0.0106±0.0019±0.0010. Further, we report new measurements of Γ(D0→KS0KS0KS0)Γ(D0→K¯0π+π−)=0.0179±0.0027±0.0026, Γ(D0→K0K¯0)Γ(D0→K¯0π+π−)=0.0144±0.0032±0.0016, and Γ(D0→KS0KS0π+π−)Γ(D0→K¯0π+π−)=0.0208±0.0035±0.0021 where the first error is statistical and the second is systematic.
We present a new measurement of the branching ratio of the Cabibbo suppressed decay D0→π−μ+ν relative to the Cabibbo favored decay D0→K−μ+ν and an improved measurement of the ratio |f+π(0)/f+K(0)|. ...Our results are 0.074±0.008±0.007 for the branching ratio and 0.85±0.04±0.04±0.01 for the form factor ratio, respectively.
Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay D0→K¯0π−μ+ν. Using a model that includes a K¯0π−s-wave component, ...we measure the form factor ratios to be rv=1.71±0.68±0.34 and r2=0.91±0.37±0.10 and the s-wave amplitude to be A=0.35±0.22±0.05 GeV−1. Finally, we measure the vector semileptonic branching ratio Γ(D0→K*(892)−μ+ν)Γ(D0→K¯0π−π+)=0.337±0.034±0.013.
Using a large sample of
D
0
→
K
−
μ
+
ν
and
D
0
→
π
−
μ
+
ν
decays collected by the FOCUS photoproduction experiment at Fermilab, we present new measurements of the
q
2
dependence for the
f
+
(
q
2
)
...form factor. These measured
f
+
(
q
2
)
form factors are fit to common parameterizations such as the pole dominance form and compared to recent unquenched Lattice QCD calculations. We find
m
pole
=
1.93
±
0.05
±
0.03
GeV
/
c
2
for
D
0
→
K
−
μ
+
ν
and
m
pole
=
1.91
−0.15
+0.30
±
0.07
GeV
/
c
2
for
D
0
→
π
−
μ
+
ν
and
f
−
(
K
)
(
0
)
/
f
+
(
K
)
(
0
)
=
−
1.7
−1.4
+1.5
±
0.3
.