63,764 research outputs found
Constraints on color dipole-nucleon cross section from diffractive heavy quarkonium production
We study the hard color dipole-nucleon cross section within perturbative QCD
and discuss its relation to observables in diffractive leptoproduction of heavy
quarkonium. The dipole cross section calculated with the unintegrated gluon
density of the nucleon substantially differs from the well-known perturbative
form for fm, where is the transverse
separation of the dipole. We show the measured ratio of to
photoproduction cross sections constrains the dipole cross section at
intermediate , and in fact excludes the simple
behavior. We also calculate the -slopes of the diffractive productions. We emphasize the difference of -slopes, , is dominated by the dipole-nucleon dynamics. This difference is
found to be about with our dipole cross section.Comment: 4 pages, 5 figures, to be published in proceedings of International
Workshop on Diffraction in High-Energy Physics (Diffraction2000
Large-scale mapping observations of the CI(3P1-3P0) and CO(J=3-2) lines toward the Orion A molecular cloud
Large scale mapping observations of the 3P1-3P0 fine structure transition of
atomic carbon (CI, 492 GHz) and the J=3-2 transition of CO (346 GHz) toward the
Orion A molecular cloud have been carried out with the Mt. Fuji
submillimeter-wave telescope. The observations cover 9 square degrees, and
include the Orion nebula M42 and the L1641 dark cloud complex. The CI emission
extends over almost the entire region of the Orion A cloud and is surprisingly
similar to that of 13CO(J=1-0).The CO(J=3-2) emission shows a more featureless
and extended distribution than CI.The CI/CO(J=3-2) integrated intensity ratio
shows a spatial gradient running from the north (0.10) to the south (1.2) of
the Orion A cloud, which we interpret as a consequence of the temperature
gradient. On the other hand, the CI/13CO(J=1-0) intensity ratio shows no
systematic gradient. We have found a good correlation between the CI and
13CO(J=1-0) intensities over the Orion A cloud. This result is discussed on the
basis of photodissociation region models.Comment: Text file is 13 pages long, and 3 figure files (pdf format). NRO
Report No. 508 (1999). University of Tokyo, Resceu 41/9
Universality of the rho-meson coupling in effective field theory
It is shown that both the universal coupling of the rho-meson and the
Kawarabayashi-Suzuki-Riadzuddin-Fayyazuddin expression for the magnitude of its
coupling constant follow from the requirement that chiral perturbation theory
of pions, nucleons, and rho-mesons is a consistent effective field theory. The
prerequisite of the derivation is that all ultraviolet divergences can be
absorbed in the redefinition of fields and the available parameters of the most
general effective Lagrangian.Comment: 4 pages, 2 figures, REVTeX 4, accepted for publication in PR
Manganese-superoxide dismutase in endothelial cells : Localization and mechanism of induction
Manganese-superoxide dismutase in endothelial cells: localization and mechanism of induction, K. Suzuki, H. Tatsumi, S. Satoh, T. Senda, T. Nakata, J. Fujii, N. Taniguchi, American Journal of Physiology - Heart and Circulatory Physiology Oct 1993, 265 (4) H1173-H1178
Search for X(3872) in gamma gamma Fusion and ISR at CLEO
We report on a search for the X(3872) state using 15.1 fb^{-1} of e+ e-
annihilation data taken with the CLEO III detector 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 are made
by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872)
decay into J/psi pi+ pi-. No signals are observed in either case, and 90%
confidence upper limits are established as (2J+1)Gamma_{gammagamma}(X(3872))B(X
-> J/psi pi+ pi-) J/psi pi+ pi-) < 8.3
eV.Comment: 4 pages, 2 figures, to appear in the proceedings of the 1st Meeting
of the APS Topical Group on Hadronic Physics, Fermilab, Oct. 24-26, 200
Effective Operator Treatment of the Lipkin Model
We analyze the Lipkin Model using effective operator techniques. We present
both analytical and numerical results for effective Hamiltonians. The accuracy
of the cluster approximation is investigated.Comment: To appear in Phys.Rev.
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