8,720 research outputs found
Observation of a Narrow Resonance of Mass 2.46 GeV/c^2 in the D_s^*+\pi^0 Final State, and Confirmation of the D_sJ^*(2317)
Using 13.5 fb^{-1} of e^+e^- annihilation data collected with the CLEO-II
detector, we have observed a new narrow resonance in the D_s^*\pi^0 final
state, with a mass near 2.46 GeV/c^2. The search for such a state was motivated
by the recent discovery by the BaBar Collaboration of a narrow state at 2.32
GeV/c^2, the D_{sJ}^*(2317)^+, that decays to D_s\pi^0. Reconstructing the
D_s\pi^0 and D_s^*\pi^0 final states in CLEO data, we observe a peak in each of
the corresponding reconstructed mass difference distributions, \Delta
M_{D_s\pi^0} = M(D_s\pi^0) - M(D_s) and \Delta M_{D_s^*\pi^0} = M(D_s^*\pi^0) -
M(D_s^*), both of them at values around 350 MeV/c^2. These peaks constitute
statistically significant evidence for two distinct states, at 2.32 and 2.46
GeV/c^2, taking into account the background source that each state comprises
for the other in light of the nearly identical values of \Delta M observed for
the two peaks. We have measured the mean mass differences \Delta M_{D_s\pi^0} =
350.4 \pm 1.2[stat.] \pm 1.0 [syst.] MeV/c^2 for the state,
and \Delta M_{D_s^*\pi^0} = 351.6 \pm 1.7[stat.] \pm 1.0 [syst.] MeV/c^2 for
the new state at 2.46 GeV/c^2. We have also searched, but find no evidence, for
decays of D_{sJ}^*(2317) into the alternate final states D_s^*\gamma,
D_s\gamma, and D_s\pi^+\pi^-. The observations of the two states at 2.32 and
2.46 GeV/c^2, in the D_s\pi^0 and D_s^*\pi^0 decay channels respectively, are
consistent with their possible interpretations as c s-bar mesons with orbital
angular momentum L=1, and spin-parity J^P = 0^+ and 1^+.Comment: 12 pages postscript, Updated Author List, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to 8th CIPANP May 200
Measurement of sigma_Total in e+e- Annihilations Below 10.56 GeV
Using the CLEO III detector, we measure absolute cross sections for e+e- ->
hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. R, the
ratio of hadronic and muon pair production cross sections, is measured at these
energies with a r.m.s. error <2% allowing determinations of the strong coupling
alpha_s. Using the expected evolution of alpha_s with energy we find
alpha_s(M_Z^2)=0.126 +/- 0.005 ^{+0.015}_{-0.011}, and
Lambda=0.31^{+0.09+0.29}_{-0.08-0.21}.Comment: Comments: Presented at "The 2007 Europhysics Conference on High
Energy Physics," Manchester, England, 19-25 July 2007, to appear in the
proceedings. Three pages, 1 figur
Simulation of a Hybrid Optical/Radio/Acoustic Extension to IceCube for EeV Neutrino Detection
Astrophysical neutrinos at EeV energies promise to be an interesting
source for astrophysics and particle physics. Detecting the predicted
cosmogenic (``GZK'') neutrinos at 10 - 10 eV would test models of
cosmic ray production at these energies and probe particle physics at 100
TeV center-of-mass energy. While IceCube could detect 1 GZK event per
year, it is necessary to detect 10 or more events per year in order to study
temporal, angular, and spectral distributions. The IceCube observatory may be
able to achieve such event rates with an extension including optical, radio,
and acoustic receivers. We present results from simulating such a hybrid
detector.Comment: 4 pages, 2 figures; to appear in the Proceedings of the 29th ICRC,
Pune, Indi
Relativistic Magnetic Monopole Flux Constraints from RICE
We report an upper limit on the flux of relativistic monopoles based on the
non-observation of in-ice showers by the Radio Ice Cherenkov Experiment (RICE)
at the South Pole. We obtain a 95% C.L. limit of order 10^{-18}/(cm^2-s-sr) for
intermediate mass monopoles of 10^7<gamma<10^{12} at the anticipated energy
E=10^{16} GeV. This bound is over an order of magnitude stronger than all
previously published experimental limits for this range of boost parameters
gamma, and exceeds two orders of magnitude improvement over most of the range.
We review the physics of radio detection, describe a Monte Carlo simulation
including continuous and stochastic energy losses, and compare to previous
experimental limits.Comment: 16 pages, 6 figures. Accepted for publication in Phys. Rev. D. Minor
revisions, including expanded discussion of monopole energy uncertaint
radiative decays to light quark jets and color octet mechanism
We study radiative decays of to light quark jets in
nonrelativistic QCD by taking both the color singlet and color octet
operators into consideration. The cut for quark jet energy and cut for the
angle between two quark jets are introduced. The sensitivity to the soft and
collinear singularities in the loop integrals are greatly reduced by these
cuts. With the jet energy cut of about 1 GeV, and the jet angle cut of about
, the branching ratio for is found to be
from color singlet contributions. The color octet
contributions could be much larger than that of color singlet, depending on the
estimate of the color octet matrix elements. This process may provide a new
test for the color octet mechanism in nonrelativistic QCD.Comment: journal version; a few references adde
Charm meson resonances in decays
Motivated by recent experimental results we reconsider semileptonic decays within a model which combines heavy quark symmetry and
properties of the chiral Lagrangian. We include excited charm meson states,
some of them recently observed, in our Lagrangian and determine their impact on
the charm meson semileptonic form factors. We find that the inclusion of
excited charm meson states in the model leads to a rather good agreement with
the experimental results on the shape of the form factor. We
also calculate branching ratios for all decays.Comment: 9 pages, 4 figures; minor corrections, added some discussion, version
as publishe
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