6,676 research outputs found
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
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
Study of tau Decays to Four-Hadron Final States with Kaons
The tau decays to four hadrons have been studied with the CLEO III detector
at the Cornell Electron Storage Ring (CESR) using (7.56 +- 0.15) fb^{-1} of
data collected near the Y(4S) resonance. We present the first statistically
significant measurements of B(tau- -> K- pi+pi- pi0 nu, excluding K^0) = (7.4
+- 0.8 +- 1.1) x 10^{-4} and B(tau--> K- K+ pi- pi0 nu) = (5.5 +- 1.4 +- 1.2) x
10^{-5}, including the first observation of the decay, tau- -> K- omega nu,
with branching fraction (4.1 +- 0.6 +- 0.7) x 10^{-4}. We also publish the
first upper limit for B(tau- -> K- K+ K- pi0 nu) < 4.8 (6.1) x 10^{-6} at 90%
(95%) confidence level (C.L.).Comment: 9 pages postscript, also available from
http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR
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
A Study of the Decays D^0 --> pi^- e^+ nu_e, D^0 --> K^- e^+ nu_e, D^+ --> pi^0 e^+ nu_e, and D^+ --> barK^0 e^+ nu_e
Using 1.8 million DDbar pairs and a neutrino reconstruction technique, we
have studied the decays D^0 -> K^- e^+ nu_e, D^0 -> pi^- e^+ nu_e, D^+ ->
Kbar^0 e^+ nu_e, and D^+ -> pi^0 e^+ nu_e. We find B(D^0 -> pi^- e^+ nu_e) =
0.299(11)(9)%, B(D^+ -> pi^0 e^+ nu_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+ nu_e)
= 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%. In addition, form
factors are studied through fits to the partial branching fractions obtained in
five q^2 ranges. By combining our results with recent unquenched lattice
calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106).Comment: 9 pages, postscript also available through
http://www.lns.cornell.edu/public/CLNS/2006/, submitted to PR
The Search for eta(1440) --> K^0_S K^pm \pi^mp in Two-Photon Fusion at CLEO
We analyze 13.8 \rm fb^{-1} of the integrated e^+e^- luminosity collected at
10.6 GeV center-of-mass energy with the CLEO II and CLEO II.V detectors to
study exclusive two-photon production of hadrons with masses below 1.7{\rm \
GeV/c^2} decaying into the K^0_S K^\pm \pi^\mp final state. We observe two
statistically significant enhancements in the \eta(1440) mass region. These
enhancements have large transverse momentum which rules them out as being due
to pseudoscalar resonances but is consistent with the production of
axial-vector mesons. We use tagged two-photon events to study the properties of
the observed enhancements and associate them with the production of f_1(1285)
and f_1(1420). Our non-observation of \eta(1440) is inconsistent by more than
two standard deviations with the first observation of this resonance in
two-photon collisions by the L3 experiment. We present our estimates for 90%
confidence level upper limits on the products of two-photon partial widths of
pseudoscalar hadrons and their branching fractions into
K^0_S(\pi^+\pi^-)K^\pm\pi^\mp.Comment: 24 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2004/, 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
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
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
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
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