275 research outputs found
Measurement of the D+ and Ds+ decays into K+K-K+
We present the first clear observation of the doubly Cabibbo suppressed decay
D+ --> K-K+K+ and the first observation of the singly Cabibbo suppressed decay
Ds+ --> K-K+K+. These signals have been obtained by analyzing the high
statistics sample of photoproduced charm particles of the FOCUS(E831)
experiment at Fermilab. We measure the following relative branching ratios:
Gamma(D+ --> K-K+K+)/Gamma(D+ --> K-pi+pi+) = (9.49 +/- 2.17(statistical) +/-
0.22(systematic))x10^-4 and Gamma(Ds+ --> K-K+K+)/Gamma(Ds+ --> K-K+pi+) =
(8.95 +/- 2.12(statistical) +2.24(syst.) -2.31(syst.))x10^-3.Comment: 10 pages, 8 figure
A Non-parametric Approach to the D+ to K*0bar mu+ nu Form Factors
Using a large sample of D+ -> K- pi+ mu+ nu decays collected by the FOCUS
photoproduction experiment at Fermilab, we present the first measurements of
the helicity basis form factors free from the assumption of spectroscopic pole
dominance. We also present the first information on the form factor that
controls the s-wave interference discussed in a previous paper by the FOCUS
collaboration. We find reasonable agreement with the usual assumption of
spectroscopic pole dominance and measured form factor ratios.Comment: 14 pages, 5 figures, and 2 tables. We updated the previous version by
changing some words, removing one plot, and adding two tables. These changes
are mostly stylisti
New Measurements of the D+ to K* mu nu Form Factor Ratios
Using a large sample of D+ to K- pi+ mu+ nu decays collected by the FOCUS
photoproduction experiment at Fermilab, we present new measurements of two
semileptonic form factor ratios: rv and r2. We find rv = 1.504 \pm 0.057 \pm
0.039 and r2 = 0.875 \pm 0.049 \pm 0.064. Our form factor results include the
effects of the s-wave interference discussed in a previous paper.Comment: 12 pages, 5 figure
Charm-anticharm baryon production asymmetries in photon-nucleon interactions
We report measurements of the charm-anticharm production asymmetries for
, , , ,
, and baryons from the Fermilab
photoproduction experiment FOCUS (E831). These asymmetries are integrated over
the region where the spectrometer has good acceptance. In addition, we have
obtained results for the photoproduction asymmetries of the baryons
as functions of , , and . The integrated asymmetry for
production, , is ,
significantly different from zero. The asymmetries of the excited states are
consistent with the asymmetry.Comment: 12 pages, 9 figures, 1 tabl
Measurements of the Sigma_c^0 and Sigma_c^{++} Mass Splittings
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.Comment: 10 pages, 2 figure
Study of Hadronic Five-Body Decays of Charmed Mesons Involving
We study the decay of and mesons into five-body final states
including a and report the discovery of the decay mode . The branching ratio for the new mode is
{} = 0.1020.029.
We also determine the branching ratio of {} =
0.0950.007 as well as an upper limit for {}
0.054 (90% CL). An analysis of the resonant substructure for is also performed
Study of Lambda/c+ Cabibbo Favored Decays Containing a Lambda Baryon in the Final State
Using data from the FOCUS experiment (FNAL-E831), we study the decay of
baryons into final states containing a hyperon. The
branching fractions of into , and relative to that into are
measured to be , and
, respectively. We also report new measurements of
, and . Further, an analysis of the subresonant structure for the
decay mode is presented.Comment: 14 pages, 6 figures, 3 tables, Submitted to Physics Letter
Measurement of the Ratio of the Vector to Pseudoscalar Charm Semileptonic Decay Rate \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)
Using a high statistics sample of photo-produced charm particles from the
FOCUS experiment at Fermilab, we report on the measurement of the ratio of
semileptonic rates \Gamma(D+ > ANTI-K pi mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)=
0.625 +/- 0.045 +/- 0.034. Allowing for the K pi S-wave interference measured
previously by FOCUS, we extract the vector to pseudoscalar ratio \Gamma(D+ >
ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.594 +/- 0.043 +/- 0.033 and the
ratio \Gamma(D+ > ANTI-K0 mu+ nu)/\Gamma(D+ > K- pi+ pi+)= 1.019 +/- 0.076 +/-
0.065. Our results show a lower ratio for \Gamma(D > K* \ell nu})/\Gamma(D > K
\ell nu) than has been reported recently and indicate the current world average
branching fractions for the decays D+ >ANTI-K0(mu+, e+) nu are low. Using the
PDG world average for B(D+ > K- pi+ pi+) we extract B(D+ > ANIT-K0 mu+
nu)=(9.27 +/- 0.69 +/- 0.59 +/- 0.61)%.Comment: 15 pages, 1 figur
Search for and Using Genetic Programming Event Selection
We apply a genetic programming technique to search for the double Cabibbo
suppressed decays and .
We normalize these decays to their Cabibbo favored partners and find
\Lambda_c^+ \to p K^+ \pi^-\Lambda_c^+ \to p K^-
\pi^+ and D_s^+ \to K^+ K^+
\pi^-D_s^+ \to K^+ K^- \pi^+ where
the first errors are statistical and the second are systematic. Expressed as
90% confidence levels (CL), we find and respectively.
This is the first successful use of genetic programming in a high energy
physics data analysis.Comment: 10 page
Measurements of Branching Ratios
Using data collected by the fixed target Fermilab experiment FOCUS, we
measure the branching ratios of the Cabibbo favored decays , , and relative to to be
, , and ,
respectively. We report the first observation of the Cabibbo suppressed decay
and we measure the branching ratio relative to
to be . We also set 90%
confidence level upper limits for and relative to to
be 0.12 and 0.05, respectively. We find an indication of the decays and and set
90% confidence level upper limits for the branching ratios with respect to
to be 0.12 and 1.72, respectively. Finally, we
determine the 90% C.L. upper limit for the resonant contribution relative to to be 0.10.Comment: 14 pages, 8 figure
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