4,105 research outputs found
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
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
Observation of the ^1P_1 State of Charmonium
The spin-singlet P-wave state of charmonium, hc(1P1), has been observed in
the decay psi(2S) -> pi0 hc followed by hc -> gamma etac. Inclusive and
exclusive analyses of the M(hc) spectrum have been performed. Two complementary
inclusive analyses select either a range of energies for the photon emitted in
hc -> gamma etac or a range of values of M(etac). These analyses, consistent
with one another within statistics, yield M(h_c) =[3524.9 +/- 0.7 (stat) +/-
0.4 (sys)]MeV/c^2 and a product of the branching ratios B_psi(psi(2S) -> pi0
hc) x B_h(hc -> gamma etac) = [3.5 +/- 1.0 (stat) +/- 0.7 (sys)] x 10^{-4}.
When the etac is reconstructed in seven exclusive decay modes, 17.5 +/- 4.5 hc
events are seen with an average mass M(hc) = [3523.6 +/- 0.9 (stat) +/- 0.5
(sys)] MeV/c^2, and B_psi x B_h = [5.3 +/- 1.5 (stat) +/- 1.0 (sys)] x 10^{-4}.
Because the inclusive and exclusive data samples are largely independent they
are combined to yield an overall mass M(hc) = [3524.4 +/- 0.6 (stat) +/- 0.4
(sys)]MeV/c^2 and product of branching ratios B_psi x B_h = [4.0 +/- 0.8 (stat)
+/- 0.7 (sys)] x 10^{-4}. The hc mass implies a P-wave hyperfine splitting
Delta M_{HF}(1P) \equiv M(1^3P)-M(1^1P_1) = [1.0 +/- 0.6 (stat) +/- 0.4 (sys)]
MeV/c^2.Comment: 38 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR
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
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Asian outflow and trans-Pacific transport of carbon monoxide and ozone pollution: An integrated satellite, aircraft, and model perspective
Satellite observations of carbon monoxide (CO) from the Measurements of Pollution in the Troposphere (MOPITT) instrument are combined with measurements from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the northwest Pacific and with a global three-dimensional chemical transport model (GEOS-CHEM) to quantify Asian pollution outflow and its trans-Pacific transport during spring 2001. Global CO column distributions in MOPITT and GEOS-CHEM are highly correlated (R2 = 0.87), with no significant model bias. The largest regional bias is over Southeast Asia, where the model is 18% too high. A 60% decrease of regional biomass burning emissions in the model (to 39 Tg yr−1) would correct the discrepancy; this result is consistent with TRACE-P observations. MOPITT and TRACE-P also give consistent constraints on the Chinese source of CO from fuel combustion (181 Tg CO yr−1). Four major events of trans-Pacific transport of Asian pollution in spring 2001 were seen by MOPITT, in situ platforms, and GEOS-CHEM. One of them was sampled by TRACE-P (26–27 February) as a succession of pollution layers over the northeast Pacific. These layers all originated from one single event of Asian outflow that split into northern and southern plumes over the central Pacific. The northern plume (sampled at 6–8 km off California) had no ozone enhancement. The southern subsiding plume (sampled at 2–4 km west of Hawaii) contained a 8–17 ppbv ozone enhancement, driven by decomposition of peroxyacetylnitrate (PAN) to nitrogen oxides (NOx). This result suggests that PAN decomposition in trans-Pacific pollution plumes subsiding over the United States could lead to significant enhancements of surface ozone
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
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
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 \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
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
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