53,828 research outputs found
Charmonium suppression by gluon bremsstrahlung in p-A and A-B collisions
Prompt gluons are an additional source for charmonium suppression in nuclear
collisions, in particular for nucleus-nucleus collisions. These gluons are
radiated as bremsstrahlung in N-N collisions and interact inelastically with
the charmonium states while the nuclei still overlap. The spectra and mean
number of the prompt gluons are calculated perturbatively and the
gluon-Psi inelastic cross section is estimated. The integrated cross sections
for AB --> J/Psi (Psi')X for p-A and A-B collisions and the dependence on
transverse energy for S-U and Pb-Pb can be described quantitatively with some
adjustment of one parameter \sigma(gPsi).Comment: 17 pages of Latex including 10 figure
Two-body scattering in a trap and a special periodic phenomenon sensitive to the interaction
Two-body scattering of neutral particles in a trap is studied theoretically.
The control of the initial state is realized by using optical traps. The
collisions inside the trap occur repeatedly; thereby the effect of interaction
can be accumulated. Two periodic phenomena with a shorter and a much longer
period, respectively, are found. The latter is sensitive to the interaction.
Instead of measuring the differential cross section as usually does, the
measurement of the longer period and the details of the periodic behavior might
be a valid source of information on weak interactions among neutral particles.Comment: 5 pages, 5 figure
Repeating head-on collisions in an optical trap and the evaluation of spin-dependent interactions among neutral particles
A dynamic process of repeating collisions of a pair of trapped neutral
particles with weak spin-dependent interaction is designed and studied. Related
theoretical derivation and numerical calculation have been performed to study
the inherent coordinate-spin and momentum-spin correlation. Due to the
repeating collisions the effect of the weak interaction can be accumulated and
enlarged, and therefore can be eventually detected. Numerical results suggest
that the Cr-Cr interaction, which has not yet been completely clear, could be
thereby determined. The design can be in general used to determine various
interactions among neutral atoms and molecules, in particular for the
determination of very weak forces.Comment: 15 pages, 7 figure
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