569 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
Di-electron Widths of the Upsilon(1S,2S,3S) Resonances
We determine the di-electron widths of the Upsilon(1S), Upsilon(2S), and
Upsilon(3S) resonances with better than 2% precision by integrating the
cross-section of e+e- -> Upsilon over the e+e- center-of-mass energy. Using
e+e- energy scans of the Upsilon resonances at the Cornell Electron Storage
Ring and measuring Upsilon production with the CLEO detector, we find
di-electron widths of 1.354 +- 0.004 (stat) +- 0.020 (syst) keV, 0.619 +- 0.004
+- 0.010 keV, and 0.446 +- 0.004 +- 0.007 keV for the Upsilon(1S), Upsilon(2S),
and Upsilon(3S), respectively.Comment: 9 pages, 4 figures, also available through
http://www.lns.cornell.edu/public/CLNS/2005/, published in PRL; corrected
numerical values in abstrac
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 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
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
Evidence for B^(*)_s bar{B}^(*)_s Production at the Upsilon(5S)
Using data collected by the CLEO III detector at CESR, we started a series of
investigations on the Upsilon(5S) resonance decay properties. The data sample
used for this analysis consists of 0.42 fb-1 of data taken on the Upsilon(5S)
resonance, 6.34 fb-1 of data collected on the Upsilon(4S) and 2.32 fb-1 of data
taken in the continuum below the Upsilon(4S). B_s mesons are expected to decay
predominantly into D_s meson, while the lighter B mesons decay into D_s only
about 10% of the time. We exploit this difference to make a preliminary model
dependent estimate of the ratio of B_s(*) anti-B_s(*) to the total b anti-b
quark pair production at the Upsilon(5S) energy to be (21 +- 3 +- 9)%.Comment: 17 pages postscript,also available through
http://www.lns.cornell.edu/public/CONF/2004/, Presented at ICHEP Aug
16-22,2004, Beijing, Chin
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
Measurement of Interference between Electromagnetic and Strong Amplitudes in psi(2S) Decays to Two Pseudoscalar Mesons
Using a sample of 3.08 million psi(2S) decays collected at sqrt{s} = 3.686
GeV with the CLEO detector at the Cornell Electron Storage Ring, we have
measured the branching fractions for psi(2S) decays to pseudoscalar pairs
pi+pi-, K+K-, and KsKl. We obtain B(psi(2S) -> pi+pi-) < 2.1 x 10^{-5} (90%
C.L.), B(psi(2S) -> K+K-) = (6.3 +- 0.6(stat) +- 0.3(syst)) x 10^{-5}, and
B(psi(2S) -> KsKl) = (5.8 +- 0.8(stat) +- 0.4(syst)) x 10^{-5}. The branching
fractions allow extraction of the relative phase Delta = (95 +- 15) degrees and
strength ratio R = (2.5 +- 0.4) of the three-gluon and one-photon amplitudes
for these modes.Comment: 8 pages postscript,also available through this
http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR
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