3,473 research outputs found
Collider Phenomenology with Split-UED
We investigate the collider implications of Split Universal Extra Dimensions.
The non-vanishing fermion mass in the bulk, which is consistent with the
KK-parity, largely modifies the phenomenology of Minimal Universal Exta
Dimensions. We scrutinize the behavior of couplings and study the discovery
reach of the Tevatron and the LHC for level-2 Kaluza-Klein modes in the
dilepton channel, which would indicates the presence of the extra dimensions.
Observation of large event rates for dilepton resonances can result from a
nontrivial fermion mass profile along the extra dimensions, which, in turn, may
corroborate extra dimensional explanation for the observation of the positron
excess in cosmic rays.Comment: 23 pages, 15 figure
Spectroscopic determination of hole density in the ferromagnetic semiconductor GaMnAs
The measurement of the hole density in the ferromagnetic semiconductor
GaMnAs is notoriously difficult using standard transport
techniques due to the dominance of the anomalous Hall effect. Here, we report
the first spectroscopic measurement of the hole density in four
GaMnAs samples () at room temperature
using Raman scattering intensity analysis of the coupled plasmon-LO-phonon mode
and the unscreened LO phonon. The unscreened LO phonon frequency linearly
decreases as the Mn concentration increases up to 8.3%. The hole density
determined from the Raman scattering shows a monotonic increase with increasing
for , exhibiting a direct correlation to the observed .
The optical technique reported here provides an unambiguous means of
determining the hole density in this important new class of ``spintronic''
semiconductor materials.Comment: two-column format 5 pages, 4 figures, to appear in Physical Review
- …