579 research outputs found
Expert and construct validity of the Simbionix GI Mentor II endoscopy simulator for colonoscopy
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Terahertz emission from the intrinsic Josephson junctions of high-symmetry thermally-managed Bi2Sr2CaCu2O8+δ microstrip antennas
We show for high-symmetry disk, square, or equilateral triangular thin microstrip antennas of any composition respectively obeying C∞v, C4v, and C3v point group symmetries, that the transverse magnetic electromagnetic cavity mode wave functions are restricted in form to those that are one-dimensional representations of those point groups. Plots of the common nodal points of the ten lowest-energy non-radiating two-dimensional representations of each of these three symmetries are presented. For comparison with symmetry-broken disk intrinsic Josephson junction microstrip antennas constructed from the highly anisotropic layered superconductor Bi2 Sr2 CaCu2 O8+δ (BSCCO), we present plots of the ten lowest frequency orthonormal wave functions and of their emission power angular distributions. These results are compared with previous results for square and equilateral triangular thin microstrip antennas
Measurement of Interfering K^*+K^- and K^*-K^+ Amplitudes in the Decay D^0 --> K^+K^-pi^0
We have studied the Cabibbo-suppressed decay mode D^0 into K^+ K^- pi^0 using
a Dalitz plot technique and find the strong phase difference delta_D [defined
as delta_(K*^- K^+) - delta_(K*^+ K^-)] = 332 degrees +- 8 degrees +- 11
degrees and relative amplitude r_D [defined as a_(K*^- K^+) / a_(K*^+ K^-)] =
0.52 +- 0.05 +- 0.04. This measurement indicates significant destructive
interference between D^0 into K^+ (K^- pi^0)_K*^- and D^0 into K^- (K^+
pi^0)_K*^+ in the Dalitz plot region where these two modes overlap. This
analysis uses 9.0 fb^(-1) of data collected at s^(1/2) of approximately 10.58
GeV with the CLEO III detector.Comment: 10 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to Phys. Rev. D
(Rapid Communications
Confirmation of the Y(4260) Resonance Production in ISR
Using 13.3 fb^-1 of e+e- collision data taken in the Upsilon(1S-4S) region
with the CLEO III detector at the CESR collider, a search has been made for the
new resonance Y(4260) recently reported by the BaBar Collaboration. The
production of Y(4260) in initial state radiation (ISR), and its decay into
pi+pi-J/psi are confirmed. A good quality fit to our data is obtained with a
single resonance. We determine M(Y(4260))=(4284+17-16(stat)+-4(syst)) MeV/c^2,
Gamma(Y(4260))=(73+39-25(stat)+-5(syst)) MeV/c^2, and
Gamma_ee(Y(4260))xBr(Y(4260)->pi+pi-J/psi)=(8.9+3.9-3.1(stat)+-1.9(syst))
eV/c^2.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to PRD (Rapid Comm.
Search for psi(2S)--> eta_c pi^+ pi^- pi^0
Using 5.63 pb^-1 of data accumulated at the psi(2S) resonance with the CLEO
III and CLEO-c detectors corresponding to 3.08 million psi(2S) decays, a search
is performed for the decay psi(2S) -> eta_c pi^+pi^-pi^0 to test a theoretical
prediction based upon the assumption that the c \bar c pair in the psi(2S) does
not annihilate directly into three gluons but rather survives before
annihilating. No signal is observed, and a combined upper limit from six eta_c
decay modes is determined to be B(psi(2S) -> eta_c pi^+pi^-pi^0) < 1.0 x 10^-3
at 90% C.L. This upper limit is about an order of magnitude below the
theoretical expectation.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006
Search for Radiative Decays of Upsilon(1S) into eta and eta'
We report on a search for the radiative decay of Upsilon(1S) to the
pseudoscalar mesons eta and etaprime in 21.2 +/- 0.2 times 10^6 Upsilon(1S)
decays collected with the CLEO III detector at the Cornell Electron Storage
Ring (CESR). The eta meson was reconstructed in the three modes eta to
gamma-gamma, eta to pi+pi-pi0 and eta to 3pi0. The etaprime meson was
reconstructed in the mode etaprime to pi+ pi- eta with eta decaying through any
of the above three modes, and also etaprime to gamma rho, where rho decays to
pi^+ pi^-.
Five out of the seven sub-modes are found to be virtually background-free. In
four of them we find no signal candidates and in one Upsilon(1S) to
gamma-etaprime, etaprime to pi+ pi- eta, eta to pi+pi-pi0 there are two good
signal candidates, which is insufficient evidence to claim a signal. The other
two sub-modes eta to gamma-gamma and etaprime to gamma rho are background
limited, and show no excess of events in their signal regions. We combine the
results from different channels and obtain upper limits at the 90% C.L. which
are B(Upsilon(1S) to gamma eta) < 1.0 times 10^-6 and B(Upsilon(1S) to gamma
etaprime) < 1.9 times 10^-6. Our limits are an order of magnitude tighter than
the previous ones and below the predictions made by some theoretical models.Comment: 14 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR
Measurement of B[Y(5S)->Bs(*) anti-Bs(*)] Using phi Mesons
Knowledge of the Bs decay fraction of the Y(5S) resonance, fs, is important
for Bs meson studies at the Y(5S) energy. Using a data sample collected by the
CLEO III detector at CESR consisting of 0.423/fb on the Y(5S) resonance,
6.34/fb on the Y(4S) and 2.32/fb in the continuum below the Y(4S), we measure
B(Y(5S) -> phi X)=(13.8 +/- 0.7 {+2.3}{-1.5})% and B(Y(4S) -> phi X) = (7.1 +/-
0.1 +/-0.6)%; the ratio of the two rates is (1.9 +/- 0.1 {+0.3}{-0.2}). This is
the first measurement of the phi meson yield from the Y(5S). Using these rates,
and a model dependent estimate of B(Bs -> phi X), we determine fs = (24.6 +/-
2.9 {+11.0}{-5.3})%. We also update our previous independent measurement of fs
made using the inclusive Ds yields to now be (16.8 +/- 2.6 {+6.7}{-3.4)%, due
to a better estimate of the number of hadronic events. We also report the total
Y(5S) hadronic cross section above continuum to be sigma(e^+e^- ->
Y(5S))=(0.301 +/- 0.002 +/- 0.039) nb. This allows us to extract the fraction
of B mesons as (58.9+/-10.0+/-9.2)%, equal to 1-fs. averaging the three methods
gives a model dependent result of fs=(21 {+6}{-3})%.Comment: 23 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to PR
Branching Fraction Measurements of psi(2S) Decay to Baryon-Antibaryon Final States
Using 3.08 million psi(2S) decays observed in e^+e^- collisions by the CLEO
detector, we present the results of a study of the psi(2S) decaying into
baryon-antibaryon final states. We report the most precise measurements of the
following eight modes: proton-antiproton, lambda-antilambda, Xi^- antiXi^-,
Xi^0-antiXi^0 (first observation), Sigma+-antiSigma^+ (first observation), and
Sigma^0-antiSigma^0, and place upper limits for the modes, Xi^0*-antiXi^0* and
Omega^- antiOmega^-.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2005/, submitted to PR
Update of the measurement of the cross section for e^+e^- -> psi(3770) -> hadrons
We have updated our measurement of the cross section for e^+e^- -> psi(3770)
-> hadrons, our publication "Measurement of sigma(e^+e^- -> psi(3770) ->
hadrons) at E_{c.m.} = 3773 MeV", arXiv:hep-ex/0512038, Phys.Rev.Lett.96,
092002 (2006). Simultaneous with this arXiv update, we have published an
erratum in Phys.Rev.Lett.104, 159901 (2010). There, and in this update, we have
corrected a mistake in the computation of the error on the difference of the
cross sections for e^+e^- -> psi(3770) -> hadrons and e^+e^- -> psi(3770) ->
DDbar. We have also used a more recent CLEO measurement of cross section for
e^+e^- -> psi(3770) -> DDbar. From this, we obtain an upper limit on the
branching fraction for psi(3770) -> non-DDbar of 9% at 90% confidence level.Comment: 3 pages, 0 figures. This is an erratum to
Phys.Rev.Lett.96:092002,2006. Added a reference
First Observation of Upsilon(3S) --> tau tau and Tests of Lepton Universality in Upsilon Decays
Using data collected with the CLEO-III detector at the CESR e+e- collider, we
report on a first observation of the decay of the Upsilon(3S) to tau tau, and
precisely measure the ratio of branching fractions of Upsilon(nS),n=1,2,3 to
tau tau and mu mu final states, finding agreement with expectations from lepton
universality. We derive absolute branching fractions for these decays, and also
set a limit on the influence of a low mass CP-odd Higgs boson in the decay of
the Upsilon(1S).Comment: 9 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006
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