60,473 research outputs found
Constituent quark model for nuclear stopping in high energy nuclear collisions
We study the nuclear stopping in high energy nuclear collisions using the
constituent quark model. It is assumed that wounded nucleons with different
number of interacted quarks hadronize in different ways. The probabilities of
having such wounded nucleons are evaluated for proton-proton, proton-nucleus
and nucleus-nucleus collisions. After examining our model in proton-proton and
proton-nucleus collisions and fixing the hadronization functions, it is
extended to nucleus-nucleus collisions. It is used to calculate the rapidity
distribution and the rapidity shift of final state protons in nucleus-nucleus
collisions. The computed results are in good agreement with the experimental
data on ^{32}\mbox{S} +\ ^{32}\mbox{S} at AGeV and
^{208}\mbox{Pb} +\ ^{208}\mbox{Pb} at AGeV. Theoretical
predictions are also given for proton rapidity distribution in ^{197}\mbox{Au}
+\ ^{197}\mbox{Au} at AGeV (BNL-RHIC). We predict that the
nearly baryon free region will appear in the midrapidity region and the
rapidity shift is .Comment: 40 pages, 16 Postscript figures, submitted to Phys. Rev.
Factorization in graviton interactions
The study of factorization in the linearized gravity is extended to the
graviton scattering processes with a massive scalar particle, with a massless
vector boson and also with a graviton. Every transition amplitude is shown to
be completely factorized and the physical implications of their common factors
are discussed.Comment: 5 pages, Revtex 3.0, SNUTP 93-7
Two-Electron Linear Intersubband Light Absorption in a Biased Quantum Well
We point out a novel manifestation of many-body correlations in the linear
optical response of electrons confined in a quantum well. Namely, we
demonstrate that along with conventional absorption peak at frequency close to
intersubband energy, there exists an additional peak at double frequency. This
new peak is solely due to electron-electron interactions, and can be understood
as excitation of two electrons by a single photon. The actual peak lineshape is
comprised of a sharp feature, due to excitation of pairs of intersubband
plasmons, on top of a broader band due to absorption by two single-particle
excitations. The two-plasmon contribution allows to infer intersubband plasmon
dispersion from linear absorption experiments.Comment: 4 pages, 3 figures; published versio
Dynamic model of fiber bundles
A realistic continuous-time dynamics for fiber bundles is introduced and
studied both analytically and numerically. The equation of motion reproduces
known stationary-state results in the deterministic limit while the system
under non-vanishing stress always breaks down in the presence of noise.
Revealed in particular is the characteristic time evolution that the system
tends to resist the stress for considerable time, followed by sudden complete
rupture. The critical stress beyond which the complete rupture emerges is also
obtained
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