943 research outputs found
Improved Measurement of the Form Factors in the Decay Lambda_c^+ --> Lambda e^+ nu_e
Using the CLEO detector at the Cornell Electron Storage Ring, we have studied
the distribution of kinematic variables in the decay Lambda_c^+ -> Lambda e^+
nu_e. By performing a four-dimensional maximum likelihood fit, we determine the
form factor ratio, R = f_2/f_1 = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole
mass, M_{pole} = (2.21 +/- 0.08(stat) +/- 0.14(syst)) GeV/c^2, and the decay
asymmetry parameter of the Lambda_c, alpha_{Lambda_c} = -0.86 +/- 0.03(stat)
+/- 0.02(syst), for = 0.67 (GeV/c^2)^2. We compare the angular
distributions of the Lambda_c^+ and Lambda_c^- and find no evidence for
CP-violation: A_{Lambda_c} = (alpha_{Lambda_c^+} + alpha_{Lambda_c^-})/
(alpha_{Lambda_c^+} - alpha_{Lambda_c^-}) = 0.00 +/- 0.03(stat) +/- 0.01(syst)
+/- 0.02, where the third error is from the uncertainty in the world average of
the CP-violating parameter, A_{Lambda}, for Lambda -> p pi^-.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR
Branching Fractions of tau Leptons to Three Charged Hadrons
From electron-positron collision data collected with the CLEO detector
operating at CESR near \sqrt{s}=10.6 GeV, improved measurements of the
branching fractions for tau decays into three explicitly identified hadrons and
a neutrino are presented as {\cal
B}(\tau^-\to\pi^-\pi^+\pi^-\nu_\tau)=(9.13\pm0.05\pm0.46)%, {\cal B}(\tau^-\to
K^-\pi^+\pi^-\nu_\tau)=(3.84\pm0.14\pm0.38)\times10^{-3}, {\cal B}(\tau^-\to
K^-K^+\pi^-\nu_\tau)=(1.55\pm0.06\pm0.09)\times10^{-3}, and {\cal B}(\tau^-\to
K^-K^+K^-\nu_\tau)<3.7\times10^{-5} at 90% C.L., where the uncertainties are
statistical and systematic, respectively.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, to appear in Phys. Rev. Let
The importance of chemosensory clues in Aguaruna tree classification and identification
<p>Abstract</p> <p>Background</p> <p>The ethnobotanical literature still contains few detailed descriptions of the sensory criteria people use for judging membership in taxonomic categories. Olfactory criteria in particular have been explored very little. This paper will describe the importance of odor for woody plant taxonomy and identification among the Aguaruna JÃvaro of the northern Peruvian Amazon, focusing on the Aguaruna category <b><it>númi </it></b>(trees excluding palms). Aguaruna informants almost always place trees that they consider to have a similar odor together as <b><it>kumpajà </it></b>– 'companions,' a metaphor they use to describe trees that they consider to be related.</p> <p>Methods</p> <p>The research took place in several Aguaruna communities in the upper Marañón region of the Peruvian Amazon. Structured interview data focus on informant criteria for membership in various folk taxa of trees. Informants were also asked to explain what members of each group of related companions had in common. This paper focuses on odor and taste criteria that came to light during these structured interviews. Botanical voucher specimens were collected, wherever possible.</p> <p>Results</p> <p>Of the 182 tree folk genera recorded in this study, 51 (28%) were widely considered to possess a distinctive odor. Thirty nine of those (76%) were said to have odors similar to some other tree, while the other 24% had unique odors. Aguaruna informants very rarely described tree odors in non-botanical terms. Taste was used mostly to describe trees with edible fruits. Trees judged to be related were nearly always in the same botanical family.</p> <p>Conclusion</p> <p>The results of this study illustrate that odor of bark, sap, flowers, fruit and leaves are important clues that help the Aguaruna to judge the relatedness of trees found in their local environment. In contrast, taste appears to play a more limited role. The results suggest a more general ethnobotanical hypothesis that could be tested in other cultural settings: people tend to consider plants with similar odors to be related, but say that plants with unique odors are unrelated to any other plants.</p
Observation of the Hadronic Transitions Chi_{b 1,2}(2P) -> omega Upsilon(1S)
The CLEO Collaboration has observed the first hadronic transition among
bottomonium (b bbar) states other than the dipion transitions among vector
states, Upsilon(nS) -> pi pi Upsilon(mS). In our study of Upsilon(3S) decays,
we find a significant signal for Upsilon(3S) -> gamma omega Upsilon(1S) that is
consistent with radiative decays Upsilon(3S) -> gamma chi_{b 1,2}(2P), followed
by chi_{b 1,2} -> omega Upsilon(1S). The branching ratios we obtain are
Br(chi_{b1} -> omega Upsilon(1S) = 1.63 (+0.35 -0.31) (+0.16 -0.15) % and
Br(chi_{b2} -> omega Upsilon(1S) = 1.10 (+0.32 -0.28) (+0.11 - 0.10)%, in which
the first error is statistical and the second is systematic.Comment: submitted to XXI Intern'l Symp on Lepton and Photon Interact'ns at
High Energies, August 2003, Fermila
Search for a Scalar Bottom Quark with Mass 3.5-4.5 GeV/
We report on a search for a supersymmetric meson with mass
between 3.5 and 4.5 GeV/ using 4.52 of integrated
luminosity produced at GeV, just below the threshold, and collected with the CLEO detector. We find no evidence
for a light scalar bottom quark.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
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
New Measurements of Upsilon(1S) Decays to Charmonium Final States
Using substantially larger data samples collected by the CLEO III detector,
we report on new measurements of the decays of Upsilon(1S) to charmonium final
states, including J/Psi, psi(2S), and chi_cJ. The latter two are first
observations of these decays. We measure the branching fractions as follows:
B(Y(1S)--> J/Psi+X)=(6.4+-0.4+-0.6)x10^-4, B(Y(1S)--> psi(2S)+X)/B(Y(1S)-->
J/Psi+X)=0.41+-0.11+-0.08, B(Y(1S)--> chi_c1+X)/B(Y(1S)-->
J/Psi+X)=0.35+-0.08+-0.06, B(Y(1S)--> chi_c2+X)/B(Y(1S)-->
J/Psi+X)=0.52+-0.12+-0.09, and B(Y(1S)--> chi_c0+X)/B(Y(1S)--> J/Psi+X)<7.4% at
90% confidence level. We also report on the momentum and angular spectra of
J/Psi's in Upsilon(1S) decay. The results are compared to predictions of the
color octet and color singlet models.Comment: 27 pages postscript,also available through
http://w4.lns.cornell.edu/public/CLNS/, submitted to PR
Observation of psi(3770)--> pi pi J/psi and Measurement of Gamma_{ee}[psi(2S)]
We observe signals for the decays psi(3770)--> X J/psi from data acquired
with the CLEO detector operating at the CESR e^+e^- collider with sqrt{s}=3773
MeV. We measure the following branching fractions B(psi(3770)--> XJ/psi) and
significances: (189 +- 20 +- 20) x 10^-5 (11.6sigma) for X=pi^+pi^-, (80 +- 25
+- 16) x 10^-5 (3.4sigma) for X=pi^0pi^0, and (87 +- 33 +- 22) x 10^-5
(3.5sigma) for X=eta, where the errors are statistical and systematic,
respectively. The radiative return process e^+e^- -->gamma psi(2S) populates
the same event sample and is used to measure Gamma_{ee}[psi(2S)]=(2.54 +- 0.03
+- 0.11) keV.Comment: 13 ages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR
Observation of a Narrow Resonance of Mass 2.46 GeV/c^2 Decaying to D_s^*+ pi^0 and Confirmation of the D_sJ^* (2317) State
Using 13.5 inverse fb of e+e- annihilation data collected with the CLEO II
detector we have observed a narrow resonance in the Ds*+pi0 final state, with a
mass near 2.46 GeV. The search for such a state was motivated by the recent
discovery by the BaBar Collaboration of a narrow state at 2.32 GeV, the
DsJ*(2317)+ that decays to Ds+pi0. Reconstructing the Ds+pi0 and Ds*+pi0 final
states in CLEO data, we observe peaks in both of the corresponding
reconstructed mass difference distributions, dM(Dspi0)=M(Dspi0)-M(Ds) and
dM(Ds*pi0)=M(Ds*pi0)-M(Ds*), both of them at values near 350 MeV. We interpret
these peaks as signatures of two distinct states, the DsJ*(2317)+ plus a new
state, designated as the DsJ(2463)+. Because of the similar dM values, each of
these states represents a source of background for the other if photons are
lost, ignored or added. A quantitative accounting of these reflections confirms
that both states exist. We have measured the mean mass differences
= 350.0 +/- 1.2 [stat] +/- 1.0 [syst] MeV for the DsJ*(2317) state, and
= 351.2 +/- 1.7 [stat] +/- 1.0 [syst] MeV for the new DsJ(2463)+
state. We have also searched, but find no evidence, for decays of the two
states via the channels Ds*+gamma, Ds+gamma, and Ds+pi+pi-. The observations of
the two states at 2.32 and 2.46 GeV, in the Ds+pi0 and Ds*+pi0 decay channels
respectively, are consistent with their interpretations as (c anti-strange)
mesons with orbital angular momentum L=1, and spin-parities of 0+ and 1+.Comment: 16 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, version to be published in Physical
Review D; minor modifications and fixes to typographical errors, plus an
added section on production properties. The main results are unchanged; they
supersede those reported in hep-ex/030501
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