2,277 research outputs found
Exploratory electromagnetic thruster research, phase 3, 23 June - 23 December 1969
Performance evaluation of MPD arc jets operating in quasi-steady mode
Diffraction and the Gluon Mass
We recently proposed a QCD-Pomeron described by the exchange of two
non-perturbative gluons characterized by a dynamically generated gluon mass. It
is here shown that data on elastic scattering, exclusive production in
deep inelastic scattering and the -nucleon total cross-section can be
successfully described in terms of a single gluon mass ~GeV. We
observe that the total cross sections of hadrons with small radii, such as
, have a marked dependence on the effective gluon mass.Comment: 10 pages, Latex, 3 figures available by fax or conventional mail.
MAD/PH/75
Investigation of pulsed quasi-steady MPD arc jets
Evaluation of magnetohydrodynamic arc thrusters operating in quasi-steady mode with electrode vapor as propellan
Unitarity Corrections to the Proton Structure Functions through the Dipole Picture
We study the dipole picture for the description of the deep inelastic
scattering, focusing on the structure functions which are driven directly by
the gluon distribution. One performs estimates using the effective dipole cross
section given by the Glauber-Mueller approach in QCD, which encodes the
corrections due to the unitarity effects associated with the saturation
phenomenon. We also address issues about frame invariance of the calculations
when analysing the observables.Comment: 16 pages, 8 figures. Version to be published in Phys. Rev.
Gluon density in nuclei
In this talk we present our detail study ( theory and numbers) [1] on the
shadowing corrections to the gluon structure functions for nuclei. Starting
from rather contraversial information on the nucleon structure function which
is originated by the recent HERA data, we develop the Glauber approach for the
gluon density in a nucleus based on Mueller formula [2] and estimate the value
of the shadowing corrections in this case. Than we calculate the first
corrections to the Glauber approach and show that these corrections are big.
Based on this practical observation we suggest the new evolution equation which
takes into account the shadowing corrections and solve it. We hope to convince
you that the new evolution equation gives a good theoretical tool to treat the
shadowing corrections for the gluons density in a nucleus and, therefore, it is
able to provide the theoretically reliable initial conditions for the time
evolution of the nucleus - nucleus cascade.Comment: Talk at RHIC'96, 43 pages, 23 figure
Parton saturation effects to the Drell-Yan process in the color dipole picture
We report on the results obtained in the study of the parton saturation
effects, taken into account through the multiscattering Glauber-Mueller
approach, applied to the Drell-Yan (DY) process described in the color dipole
picture. As a main result, one shows that those effects play an important role
in the estimates of the DY differential cross section atRHIC energies.Comment: To appear in the proceedings of the VIII International Workshop on
Hadron Physics 200
Scaling violation and shadowing corrections at HERA
We study the value of shadowing corrections (SC) in HERA kinematic region in
Glauber - Mueller approach. Since the Glauber - Mueller approach was proven in
perturbative QCD in the double logarithmic approximation (DLA), we develop the
DLA approach for deep inelastic structure function which takes into account the
SC. Our estimates show small SC for in HERA kinematic region while they
turn out to be sizable for the gluon structure function. We compare our
estimates with those for gluon distribution in leading order (LO) and next to
leading order (NLO) in the DGLAP evolution equations.Comment: 9pp,6 figures in eps file
Inclusive hadron and photon production at LHC in dipole momentum space
Using a momentum space model for the dipole scattering amplitude we present
an analysis of the saturation effects at LHC energies, describing the data on
proton-proton and proton-lead collisions. The model is based on the asymptotic
solutions of the Balitsky-Kovchegov equation, being ideal in the saturation
domain where the target wave function has a high occupation number. We also
make predictions for the nuclear modification ratios on charged hadron and
prompt photon production in the forward region, where the high parton density
effects are important.Comment: New section added and typos corrected. To be published in PR
Quasi-steady plasma accelerators
Results are reported from a continued study of MPD thrusters operating in the quasi-steady mode and using electrode vapor as the propellant. Testing methods were refined, and performance data is now available for a fairly wide range of thruster geometries. Performance was found to be strongly dependent on thruster geometry, with some designs showing approximately twice the efficiency obtained during the preceding contract period. The radial clearance between electrodes, the attachment point of the arc on the cathode, and the electrical resistance of the electrodes appear to be important design variables
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