16,728 research outputs found
Effect of sea quarks on the single-spin asymmetries in polarized pp collisions at RHIC
We calculate the single-spin asymmetries of
bosons produced in polarized pp collisions with the valence part of the up and
down quark helicity distributions modeled by the light-cone
quark-spectator-diquark model while the sea part helicity distributions of the
up and down quarks treated as parametrization. Comparing our results with those
from experimental data at RHIC, we find that the helicity distributions of sea
quarks play an important role in the determination of the shapes of
. It is shown that is sensitive to , while to intuitively. The experimental
data of the polarized structure functions and the sum of helicities are also
important to constrain the sizes of quark helicity distributions both for the
sea part and the valence part of the nucleon.Comment: 19 latex pages, 5 figures, final version for publicatio
Zener Tunneling in Semiconducting Nanotube and Graphene Nanoribbon p-n Junctions
A theory is developed for interband tunneling in semiconducting carbon
nanotube and graphene nanoribbon p-n junction diodes. Characteristic length and
energy scales that dictate the tunneling probabilities and currents are
evaluated. By comparing the Zener tunneling processes in these structures to
traditional group IV and III-V semiconductors, it is proved that for identical
bandgaps, carbon based 1D structures have higher tunneling probabilities. The
high tunneling current magnitudes for 1D carbon structures suggest the distinct
feasibility of high-performance tunneling-based field-effect transistors.Comment: 4 Pages, 2 Figure
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