300 research outputs found
Performance of a C4F8O Gas Radiator Ring Imaging Cherenkov Detector Using Multi-anode Photomultiplier Tubes
We report on test results of a novel ring imaging Cherenkov (RICH) detection
system consisting of a 3 meter long gaseous C4F8O radiator, a focusing mirror,
and a photon detector array based on Hamamatsu multi-anode photomultiplier
tubes. This system was developed to identify charged particles in the momentum
range from 3-70 GeV/c for the BTeV experiment.Comment: 28 pages, 23 figures, submitted to Nuclear Instruments and Method
Symmetries and observables in topological gravity
After a brief review of topological gravity, we present a superspace approach
to this theory. This formulation allows us to recover in a natural manner
various known results and to gain some insight into the precise relationship
between different approaches to topological gravity. Though the main focus of
our work is on the vielbein formalism, we also discuss the metric approach and
its relationship with the former formalism.Comment: 34 pages; a few explanations added in subsection 2.2.1, published
version of pape
The Cleo Rich Detector
We describe the design, construction and performance of a Ring Imaging
Cherenkov Detector (RICH) constructed to identify charged particles in the CLEO
experiment. Cherenkov radiation occurs in LiF crystals, both planar and ones
with a novel ``sawtooth''-shaped exit surface. Photons in the wavelength
interval 135--165 nm are detected using multi-wire chambers filled with a
mixture of methane gas and triethylamine vapor. Excellent pion/kaon separation
is demonstrated.Comment: 75 pages, 57 figures, (updated July 26, 2005 to reflect reviewers
comments), to be published in NIM
Genetic comparison of sickle cell anaemia cohorts from Brazil and the United States reveals high levels of divergence
Genetic analysis of admixed populations raises special concerns with regard to study design and data processing, particularly to avoid population stratification biases. The point mutation responsible for sickle cell anaemia codes for a variant hemoglobin, sickle hemoglobin or HbS, whose presence drives the pathophysiology of disease. Here we propose to explore ancestry and population structure in a genome-wide study with particular emphasis on chromosome 11 in two SCA admixed cohorts obtained from urban populations of Brazil (Pernambuco and Sao Paulo) and the United States (Pennsylvania). Ancestry inference showed different proportions of European, African and American backgrounds in the composition of our samples. Brazilians were more admixed, had a lower African background (43% vs. 78% on the genomic level and 44% vs. 76% on chromosome 11) and presented a signature of positive selection and Iberian introgression in the HbS region, driving a high differentiation of this locus between the two cohorts. The genetic structures of the SCA cohorts from Brazil and US differ considerably on the genome-wide, chromosome 11 and HbS mutation locus levels9CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQCOORDENAĂĂO DE APERFEIĂOAMENTO DE PESSOAL DE NĂVEL SUPERIOR - CAPESFUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESP8367/2011-1; 150398/2013-1; 304455/2012-1; 310938/2014-7; 305218/2017-48367/2011-1; 150398/2013-1; 304455/2012-1; 310938/2014-7; 305218/2017-42008/57441-0; 2014/00984-3; 2012/06438-5; 2015/13152-9; 2008/10596-
Measurement of \cal{B}(D^+ --> mu^+ nu) and the Pseudoscalar Decay Constant
In 60 pb-1 of data taken on the psi(3770) resonance with the CLEO-c detector,
we find 8 D+ to mu+ nu event candidates that are mostly signal, containing only
1 estimated background. Using this statistically compelling sample, we measure
preliminary values of B(D+ to mu+ nu) = (3.5 +- 1.4 +- 0.6)*10^{-4}, and
determine f_{D+} =(201+- 41+- 17) MeV.Comment: 17 pages postscript, also available through
http://www.lns.cornell.edu/public/CONF/2004/, Presented at ICHEP Aug
16-22,2004, Beijing, Chin
Radiative Decays of the Upsilon(1S) to a Pair of Charged Hadrons
Using data obtained with the CLEO~III detector, running at the Cornell
Electron Storage Ring (CESR), we report on a new study of exclusive radiative
Upsilon(1S) decays into the final states gamma pi^+ pi^-, gamma K^+ K^-, and
gamma p pbar.. We present branching ratio measurements for the decay modes
Upsilon(1S) to gamma f_2(1270), Upsilon(1S) to gamma f_2'(1525), and
Upsilon(1S) to gamma K^+K^-; helicity production ratios for f_2(1270) and
f_2'(1525); upper limits for the decay Upsilon(1S) to gamma f_J(2200), with
f_J(2220) to pi^+ pi^-, K^+ K^-, p pbar; and an upper limit for the decay
Upsilon(1S) to gamma X(1860), with X(1860) to gamma p pbar.Comment: 17 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
Search for X(3872) in gamma gamma Fusion and ISR at CLEO
We report on a search for the recently reported X(3872) state using 15.1
fb^{-1} e+ e- data taken in the \sqrt{s} = 9.46-11.30 GeV region. Separate
searches for the production of X(3872) in untagged gamma-gamma fusion and e+ e-
annihilation following initial state radiation (ISR) are made by taking
advantage of the unique correlation of J/psi -> l+ l- in X(3872) decay to pi+
pi- J/psi. No signals are observed in either case, and 90% confidence upper
limits are established as (2J+1)\Gamma_{\gamma\gamma}B(X -> pi+ pi- J/psi) <
12.9 eV and \Gamma_{ee}B(X -> pi+ pi- J/psi) < 8.3 eV.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR
Moments of the B Meson Inclusive Semileptonic Decay Rate using Neutrino Reconstruction
We present a measurement of the composition of B meson inclusive semileptonic
decays using 9.4 fb^-1 of e^+e^- data taken with the CLEO detector at the
Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics,
the neutrino four-vector is inferred using the hermiticity of the detector. We
perform a maximum likelihood fit over the full three-dimensional differential
decay distribution for the fractional contributions from the B -> X_c l nu
processes with X_c = D, D*, D**, and nonresonant X_c, and the process B -> X_u
l nu. From the fit results we extract the first and second moments of the M_X^2
and q^2 distributions with minimum lepton-energy requirements of 1.0 GeV and
1.5 GeV. We find = 0.456 +- 0.014 +- 0.045 +- 0.109
(GeV/c^2)^2 with a minimum lepton energy of 1.0 GeV and =
0.293 +- 0.012 +- 0.033 +- 0.048 (GeV/c^2)^2 with minimum lepton energy of 1.5
GeV. The uncertainties are from statistics, detector systematic effects, and
model dependence, respectively. As a test of the HQET and OPE calculations, the
results for the M^X_c moment as a function of the minimum lepton energy
requirement are compared to the predictions.Comment: 26 pages postscript, als available through
http://w4.lns.cornell.edu/public/CLNS/, Submitted to PRD (back-to-back with
following preprint hep-ex/0403053
Measurement of Absolute Hadronic Branching Fractions of D Mesons and e^+ e^- --> D D-bar Cross Sections at the psi(3770)
Using 281 /pb of e^+ e^- collisions recorded at the psi(3770) resonance with
the CLEO-c detector at CESR, we determine absolute hadronic branching fractions
of charged and neutral D mesons using a double tag technique. Among
measurements for three D^0 and six D^+ modes, we obtain reference branching
fractions B(D^0 --> K^-pi^+) = (3.891 +- 0.035 +- 0.059 +- 0.035)% and B(D^+
--> K^-pi^+pi^+) = (9.14 +- 0.10 +- 0.16 +- 0.07)%, where the first uncertainty
is statistical, the second is all systematic errors other than final state
radiation (FSR), and the third is the systematic uncertainty due to FSR. We
include FSR in these branching fractions by allowing for additional unobserved
photons in the final state. Using an independent determination of the
integrated luminosity, we also extract the cross sections sigma(e+e- --> D^0
D^0-bar) = (3.66+- 0.03 +- 0.06) nb and sigma(e+e- --> D^+ D^-) = (2.91+- 0.03
+- 0.05) nb at a center of mass energy, E_cm = 3774 +- 1 MeV.Comment: 47 pages, postscript also available through this
http://www.lns.cornell.edu/public/CLNS/2007/, to be published in PRD, updated
branching fractions using B(KS0 --> pi+ pi-) from PDG 2007, and updated text
in response to the PRD reviewe
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