2,586 research outputs found
Observation of Exclusive Two-Body B Decays to Kaons and Pions
We have studied two-body charmless hadronic decays of B mesons into the final
states , , and . Using 3.3 million pairs
collected with the CLEO-II detector, we have made the first observation of the
decays , , and the sum of and decays (an average over charge-conjugate
states is always implied). We place upper limits on branching fractions for the
remaining decay modes.Comment: 9 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of the Inclusive Semi-electronic Branching Fraction
Using the angular correlation between the emitted in a decay and the emitted in the subsequent decay, we have measured the branching fraction for the
inclusive semi-electronic decay of the meson to be: {\cal B}(D^0
\rightarrow X e^+ \nu) = [6.64 \pm 0.18 (stat.) \pm 0.29 (syst.)] \%. The
result is based on 1.7 fb of collisions recorded by the CLEO II
detector located at the Cornell Electron Storage Ring (CESR). Combining the
analysis presented in this paper with previous CLEO results we find,
\frac{{\cal B} (D^0 \rightarrow X e^+ \nu)}
{{\cal B} (D^0 \rightarrow K^- \pi^+)}
= 1.684 \pm 0.056 (stat.) \pm 0.093(syst.) and
\frac{{\cal B}(D\rightarrow K^-e^+\nu)}
{{\cal B}(D\rightarrow Xe^+\nu)}
= 0.581 \pm 0.023 (stat.) \pm 0.028(syst.).
The difference between the inclusive rate and the sum of the measured
exclusive branching fractions (measured at CLEO and other experiments) is of the inclusive rate.Comment: Latex file, 33pages, 4 figures Submitted to PR
Unfitting, uncomfortable, unacademic: a sociological reading of an interactive mobile phone app in university lectures
Abstract Scholarly literature on education technology uptake has been dominated by technological determinist readings of students’ technology use. However, in recent years there has been a move by sociologists of education to highlight how the contexts in which educational technologies are introduced are not tabula rasa but socially and culturally complex. This study approaches technology as a social construct, arguing that students construct discursive meaning of, rather than simply respond to, technologies for learning. The study explores students’ constructions of a mobile learning app that was introduced into lectures during a year-long university course. Students largely rejected the app, constructing it as unfitting for the context, a socially uncomfortable experience and an unacademic way of learning. The paper highlights the limitations of technological determinism and closes by arguing for readings of educational technologies that pay close attention to students’ voices
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
Flavor-Specific Inclusive B Decays to Charm
We have measured the branching fractions for B -> D_bar X, B -> D X, and B ->
D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum
over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these
results and some previously measured branching fractions, we obtain Br(b -> c
c_bar s) = (21.9 3.7)%, Br(b -> s g) K^-
\pi^+) = (3.69 0.20)%. Implications for the ``B semileptonic decay
problem'' (measured branching fraction being below theoretical expectations)
are discussed. The increase in the value of Br(b -> c c_bar s) due to eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of using Partila Reconstruction of
We present a measurement of the absolute branching fraction for using the reconstruction of the decay chain , where only the lepton and the low-momentum pion from
the are detected. With data collected by the CLEO II detector at the
Cornell Electron Storage Ring, we have determined .Comment: 10 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay
Using the CLEO II detector at the storage ring CESR, we have
determined the Michel parameters , , and in decay as well as the tau neutrino helicity parameter
in decay. From a data sample of
tau pairs produced at , using events of
the topology and , and the determined sign of , the combined
result of the three samples is: , , , and
. The results are in agreement with
the Standard Model V-A interaction.Comment: 18 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
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
Study of Semileptonic Decays of B Mesons to Charmed Baryons
Using data collected by the CLEO II detector at the center-of-mass energy on
or near the Upsilon(4S) resonance, we have determined the 90% confidence level
upper limit B(Bbar --> Lambda_c^+ e- X)/B(Bbar --> Lambda_c^+ X, Lambdabar_c^-
X) < 0.05 for electrons with momentum above 0.6 GeV/c. We have also derived the
ratio B(B^- --> Lambda_c^+ pbar e- nubar_e)/B(Bbar --> Lambda_c^+ pbar X) <
0.04 at the 90% confidence level and measured the ratio B(Bbar --> Lambda_c^+
pbar X)/B(Bbar --> Lambda_c^+ X, Lambdabar_c^- X) = 0.57 +- 0.05 +- 0.05.Comment: 9 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Two-Body B Meson Decays to and -- Observation of {'}K$
In a sample of 6.6 million produced B mesons we have observed decays B ->
eta' K, with branching fractions BR(B+ -> eta' K+ = 6.5 +1.5 -1.4 +- 0.9) x
and BR(B0 -> eta' K0 = 4.7 +2.7 -2.0 +- 0.9) x . We have
searched with comparable sensitivity for 17 related decays to final states
containing an eta or eta' meson accompanied by a single particle or low-lying
resonance. Our upper limits for these constrain theoretical interpretations of
the B -> eta' K signal.Comment: 12 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
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