19,291 research outputs found
Precise photoproduction of the charged top-pions at the LHC with forward detector acceptances
We study the photoproduction of the charged top-pion predicted by the top
triangle moose () model (a deconstructed version of the topcolor-assisted
technicolor model) via the processes at the 14 Large Hadron Collider ()
including next-to-leading order () corrections. Our results show
that the production cross sections and distributions are sensitive to the free
parameters and . Typical correction value is and does not depend much on as well as the forward
detector acceptances.Comment: 21pages, 7figures. arXiv admin note: text overlap with
arXiv:1201.4364 by other author
The focusing of electron flow in a bipolar Graphene ribbon with different chiralities
The focusing of electron flow in a symmetric p-n junction (PNJ) of graphene
ribbon with different chiralities is studied. Considering the PNJ with the
sharp interface, in a armchair ribbon, the electron flow emitting from
in n-region can always be focused perfectly at in p-region in the whole
Dirac fermion regime, i.e. in whole regime where is the distance
between Dirac-point energy and Fermi energy and is the nearest hopping
energy. For the bipolar ribbon with zigzag edge, however, the incoming electron
flow in n-region is perfectly converged in p-region only in a very low energy
regime with . Moreover, for a smooth PNJ, electrons are
backscattered near PNJ, which weakens the focusing effect. But the focusing
pattern still remains the same as that of the sharp PNJ. In addition, quantum
oscillation in charge density occurs due to the interference between forward
and backward scattering. Finally, in the presence of weak perpendicular
magnetic field, charge carriers are deflected in opposite directions in the
p-region and n-region. As a result, the focusing effect is smeared. The lower
energy , the easier the focusing effect is destroyed. For the high energy
(e.g. ), however, the focusing effect can still survive in a
moderate magnetic field on order of one Tesla.Comment: 29 pages, 16 figure
Symmetry and transport property of spin current induced spin-Hall effect
We study the spin current induced spin-Hall effect that a longitudinal spin
dependent chemical potential induces a transverse spin
conductances . A four terminal system with Rashba and Dresselhaus
spin-orbit interaction (SOI) in the scattering region is considered. By using
Landauer-Bttiker formula with the aid of the Green function, various
spin current induced spin-Hall conductances are calculated. With the
charge chemical potential or spin chemical potential ,
there are 16 elements for the transverse conductances where . Due to the symmetry of our
system these elements are not independent. For the system with symmetry
half of elements are zero, when the center region only exists the Rashba SOI or
Dresselhaus SOI. The numerical results show that of all the conductance
elements, the spin current induced spin-Hall conductances are usually
much greater (about one or two orders of magnitude) than the spin Hall
conductances and the reciprocal spin Hall conductances . So
the spin current induced spin-Hall effect is dominating in the present device.Comment: 7 pages, 6 figure
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