252 research outputs found
Semileptonic Branching Fraction of Charged and Neutral B Mesons
An examination of leptons in events tagged by reconstructed
decays yields semileptonic branching fractions of for charged and for neutral mesons.
This is the first measurement for charged . Assuming equality of the charged
and neutral semileptonic widths, the ratio is
equivalent to the ratio of lifetimes. A postscript version is available through
World-Wide-Web in http://w4.lns.cornell.edu/public/CLNS/1994Comment: 9 pages (in REVTEX format) Preprint CLNS94-1286, CLEO 94-1
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0
We have investigated and final states and
observed the two established charmed mesons, the with mass
MeV/c and width MeV/c and
the with mass MeV/c and width
MeV/c. Properties of these final states, including
their decay angular distributions and spin-parity assignments, have been
studied. We identify these two mesons as the doublet predicted
by HQET. We also obtain constraints on {\footnotesize } as a function of the cosine of the relative phase of the two
amplitudes in the decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by
sending mail to: [email protected]
Observation of the Isospin-Violating Decay
Using data collected with the CLEO~II detector, we have observed the
isospin-violating decay . The decay rate for this mode,
relative to the dominant radiative decay, is found to be .Comment: 8 page uuencoded postscript file, also available through
http://w4.lns.cornell.edu/public/CLN
Search for Exclusive Charmless Hadronic B Decays
We have searched for two-body charmless hadronic decays of mesons. Final
states include , , and with both charged and neutral kaons
and pions; , , and ; and , , and
. The data used in this analysis consist of 2.6~million
~pairs produced at the taken with the CLEO-II detector
at the Cornell Electron Storage Ring (CESR). We measure the branching fraction
of the sum of and to be
. In addition, we place upper
limits on individual branching fractions in the range from to
.Comment: 33 page LATEX file, uses REVTEX and psfig, 14 figures in a separate
uuencoded postscript file, postscript version also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of the branching fraction for
We have studied the leptonic decay of the resonance into tau
pairs using the CLEO II detector. A clean sample of tau pair events is
identified via events containing two charged particles where exactly one of the
particles is an identified electron. We find . The result is consistent with
expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS
94/1297, CLEO 94-20 (submitted to Physics Letters B
Measurement of the Decay Asymmetry Parameters in and
We have measured the weak decay asymmetry parameters (\aLC ) for two \LC\
decay modes. Our measurements are \aLC = -0.94^{+0.21+0.12}_{-0.06-0.06} for
the decay mode and \aLC = -0.45\pm 0.31 \pm
0.06 for the decay mode . By combining these
measurements with the previously measured decay rates, we have extracted the
parity-violating and parity-conserving amplitudes. These amplitudes are used to
test models of nonleptonic charmed baryon decay.Comment: 11 pages including the figures. Uses REVTEX and psfig macros. Figures
as uuencoded postscript. Also available as
http://w4.lns.cornell.edu/public/CLNS/1995/CLNS95-1319.p
Measurements of the Ratios and
Using the CLEO~II detector we measure , and .
We find the vector to pseudoscalar ratio, , which is similar to the
ratio found in non strange decays.Comment: 11 page uuencoded postscript file, postscript file also available
through http://w4.lns.cornell.edu/public/CLN
Observation of the Charmed Baryon Decays to , , and
We have observed two new decay modes of the charmed baryon into
and using data collected with the
CLEO II detector. We also present the first measurement of the branching
fraction for the previously observed decay mode . The branching fractions for these three modes relative to
are measured to be , , and , respectively.Comment: 12 page uuencoded postscript file, postscript file also available
through http://w4.lns.cornell.edu/public/CLN
Measurement of the B -> D^* l nu Branching Fractions and |Vcb|
We study the exclusive semileptonic B meson decays B- -> D*0 l- nu and B0 ->
D*+ l- nu using data collected with the CLEO II detector at CESR. We present
measurements of the branching fractions B(B0 -> D*+ l-nu) = 0.5/f00*
[4.49+/-0.32+/-0.39]% and B(B- -> D*0 l-nu) = 0.5/f+-*[5.13+/-0.54+/-0.64]%,
where f00 and f+- are the neutral and charged B meson production fractions at
the Upsilon(4s) resonance. Assuming isospion invariance and taking the charged
to neutral B meson lifetimes measured at higher energy machines, we determine
the ratio f+-/f00=1.04+/-0.14+/-0.13+-/-0.10; further assuming f+- + f00 = 1 we
also determine the partial width G(B->D* l nu) = 29.9+/-1.9+/-2.7+/-2.0 ns-1
(independent of f+-/f00). From this partial width we calculate B -> D* l nu
branching fractions that do not depend on f+-/f00, nor the individual B
lifetimes, but only on the charged to neutral lifetime ratio. The product of
the CKM matrix element |Vcb| times the normalization of the decay form factor
at the point of zero recoil of the D* meson, F(y=1), is determined from a
linear fit to the combined differential decay rate of the exclusive B->D* l nu
decays: |Vcb|F(y) = 0.0351 +/- 0.0019 +/- 0.0018 +/- 0.0008. Using theoretical
calculations of the form factor normalization we extract a value for |Vcb|.
LATEX (REVTEX style) file with uuencoded figures attached (uses PSBOX).
Available on WWW http://w4.lns.cornell.edu/public/CLNS/Comment: 42 pages,CLNS 94/1285, CLEO 94-2
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