1,620 research outputs found
New Results From CLEO and BES
Latest experimental results from BES in the charmonium mass region, and those
from CLEO in the bottomonium and charmonium spectroscopy are reviewed.Comment: 12 pages, 12 figures, Presented at First Meeting of the APS Topical
Group on Hadron Physics, Fermilab, Batavia, Illinois, Oct 24-26, 200
Properties of the a1 Meson from Lattice QCD
We determine the mass and decay constant of the meson using Monte Carlo
simulation of lattice QCD. We find MeV and , in good agreement with experiment.Comment: 9 page uu-encoded compressed postscript file. version appearing in
Phys. Rev. Lett. 74 (1995) 459
Axial Vector Charmonium and Bottomonium Hybrid Mass Predictions with QCD Sum-Rules
Axial vector charmonium and bottomonium hybrid masses are
determined via QCD Laplace sum-rules. Previous sum-rule studies in this channel
did not incorporate the dimension-six gluon condensate, which has been shown to
be important for and heavy quark hybrids. An updated analysis
of axial vector charmonium and bottomonium hybrids is presented, including the
effects of the dimension-six gluon condensate. The axial vector charmonium and
bottomonium hybrid masses are predicted to be 5.13 GeV and 11.32 GeV,
respectively. We discuss the implications of this result for the
charmonium-like XYZ states and the charmonium hybrid multiplet structure
observed in recent lattice calculations.Comment: 10 pages, 7 figures. Updated to match published versio
The Electromagnetic Mass Differences of Pions and Kaons
We use the Cottingham method to calculate the pion and kaon electromagnetic
mass differences with as few model dependent inputs as possible. The
constraints of chiral symmetry at low energy, QCD at high energy and
experimental data in between are used in the dispersion relation. We find
excellent agreement with experiment for the pion mass difference. The kaon mass
difference exhibits a strong violation of the lowest order prediction of
Dashen's theorem, in qualitative agreement with several other recent
calculations.Comment: 40 pages, Latex, needs axodraw. and psfig. macros, 4 figure
Measurement of the eta-Meson Mass using psi(2S) --> eta J/psi
We measure the mass of the eta meson using psi(2S) --> eta J/psi events
acquired with the CLEO-c detector operating at the CESR e+e- collider. Using
the four decay modes eta --> gamma gamma, 3pi0, pi+pi-pi0, and pi+pi-gamma, we
find M(eta)=547.785 +- 0.017 +- 0.057 MeV, in which the first uncertainty is
statistical and the second systematic. This result has an uncertainty
comparable to the two most precise previous measurements and is consistent with
that of NA48, but is inconsistent at the level of 6.5sigma with the much
smaller mass obtained by GEM.Comment: 10 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR
Determination of the D0 -> K+pi- Relative Strong Phase Using Quantum-Correlated Measurements in e+e- -> D0 D0bar at CLEO
We exploit the quantum coherence between pair-produced D0 and D0bar in
psi(3770) decays to study charm mixing, which is characterized by the
parameters x and y, and to make a first determination of the relative strong
phase \delta between doubly Cabibbo-suppressed D0 -> K+pi- and Cabibbo-favored
D0bar -> K+pi-. We analyze a sample of 1.0 million D0D0bar pairs from 281 pb^-1
of e+e- collision data collected with the CLEO-c detector at E_cm = 3.77 GeV.
By combining CLEO-c measurements with branching fraction input and
time-integrated measurements of R_M = (x^2+y^2)/2 and R_{WS} = Gamma(D0 ->
K+pi-)/Gamma(D0bar -> K+pi-) from other experiments, we find \cos\delta = 1.03
+0.31-0.17 +- 0.06, where the uncertainties are statistical and systematic,
respectively. In addition, by further including external measurements of charm
mixing parameters, we obtain an alternate measurement of \cos\delta = 1.10 +-
0.35 +- 0.07, as well as x\sin\delta = (4.4 +2.7-1.8 +- 2.9) x 10^-3 and \delta
= 22 +11-12 +9-11 degrees.Comment: 37 pages, also available through
http://www.lns.cornell.edu/public/CLNS/2007/. Incorporated referee's comment
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