3,425 research outputs found
Recent developments in the modeling of heavy quarkonia
We examine the spectra and radiative decays of the cc-bar and bb-bar systems
using a model which incorporates the complete one-loop spin-dependent
perturbative QCD short distance potential, a linear confining term including
(spin-dependent) relativistic corrections to order v^2/c^2, and a fully
relativistic treatment of the kinetic energy. We compare the predictions of
this model to experiments, including states and decays recently measured at
Belle, BaBar, CLEO and CDF.Comment: 3 pages, contribution to PANIC05, Santa Fe, NM October 200
Note on recent measurements of the \psi(1S)\to\ga \eta_C(1S) and \psi(2S)\to\ga \eta_C(1S) branching ratios
Recently published measurements of the branching ratios {\cal
B}(\psi(1S)\to\ga \eta_C(1S)) and {\cal B}(\psi(2S)\to\ga \eta_C(1S)) by the
CLEO collaboration are examined in the context of a potential model that
includes both relativistic and one-loop QCD corrections to the quark-antiquark
interaction. The prediction for the width \Gamma(\psi(1S)\to\ga \eta_C(1S))
is in excellent agreement with the new data but the prediction for
\Gamma(\psi(2S)\to\ga \eta_C(1S)) is too small. In an effort to understand
this discrepancy, we derive an upper bound on \Gamma(\psi(2S)\to\ga
\eta_C(1S)) and point out its experimental value saturates this bound.Comment: Corrected typos, addeded referenc
A "Sidewinding" Locomotion Gait for Hyper-Redundant Robots
This paper considers the kinematics of a novel form of hyper-redundant mobile robot locomotion which is analogous to the 'sidewinding' locomotion of desert snakes. This form of locomotion can be generated by a repetitive travel wave of mechanism bending. Using a continuous backbone curve model, we develop algorithms which enable travel in a uniform direction as well as changes in direction
Potential model calculations and predictions for heavy quarkonium
We investigate the spectroscopy and decays of the charmonium and upsilon
systems in a potential model consisting of a relativistic kinetic energy term,
a linear confining term including its scalar and vector relativistic
corrections and the complete perturbative one-loop quantum chromodynamic short
distance potential. The masses and wave functions of the various states are
obtained using a variational technique, which allows us to compare the results
for both perturbative and nonperturbative treatments of the potential. As well
as comparing the mass spectra, radiative widths and leptonic widths with the
available data, we include a discussion of the errors on the parameters
contained in the potential, the effect of mixing on the leptonic widths, the
Lorentz nature of the confining potential and the possible
interpretation of recently discovered charmonium-like states.Comment: Physical Review published versio
An evaluation of geomagnetic harmonic series for 1100 kilometers altitude
Geomagnetic harmonic series evaluation for 1100 kilometers altitude using satellite observation
The scaler magnetic intensity at 1100 kilometers in middle and low latitudes
Satellite borne magnetometer for measuring scalar magnetic intensities in middle and low latitudes at 1100 km altitud
The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies
We present CO observations of a large sample of ultraluminous IR galaxies out
to z = 0.3. Most of the galaxies are interacting, but not completed mergers.
All but one have high CO(1-0) luminosities, log(Lco [K-km/s-pc^2]) = 9.92 +/-
0.12. The dispersion in Lco is only 30%, less than that in the FIR luminosity.
The integrated CO intensity correlates Strongly with the 100 micron flux
density, as expected for a black body model in which the mid and far IR
radiation are optically thick. We use this model to derive sizes of the FIR and
CO emitting regions and the enclosed dynamical masses. Both the IR and CO
emission originate in regions a few hundred parsecs in radius. The median value
of Lfir/Lco = 160 Lsun/(K-km/s-pc^2), within a factor of two of the black body
limit for the observed FIR temperatures. The entire ISM is a scaled up version
of a normal galactic disk with densities a factor of 100 higher, making even
the intercloud medium a molecular region. Using three different techniques of
H2 mass estimation, we conclude that the ratio of gas mass to Lco is about a
factor of four lower than for Galactic molecular clouds, but that the gas mass
is a large fraction of the dynamical mass. Our analysis of CO emission reduces
the H2 mass from previous estimates of 2-5e10 Msun to 0.4-1.5e10 Msun, which is
in the range found for molecular gas rich spiral galaxies. A collision
involving a molecular gas rich spiral could lead to an ultraluminous galaxy
powered by central starbursts triggered by the compression of infalling
preexisting GMC's.Comment: 34 pages LaTeX with aasms.sty, 14 Postscript figures, submitted to
ApJ Higher quality versions of Figs 2a-f and 7a-c available by anonymous FTP
from ftp://sbast1.ess.sunysb.edu/solomon/
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