3,264 research outputs found
Electronic transport in Si:P delta-doped wires
Despite the importance of Si:P delta-doped wires for modern nanoelectronics,
there are currently no computational models of electron transport in these
devices. In this paper we present a nonequilibrium Green's function model for
electronic transport in a delta-doped wire, which is described by a
tight-binding Hamiltonian matrix within a single-band effective-mass
approximation. We use this transport model to calculate the current-voltage
characteristics of a number of delta-doped wires, achieving good agreement with
experiment. To motivate our transport model we have performed
density-functional calculations for a variety of delta-doped wires, each with
different donor configurations. These calculations also allow us to accurately
define the electronic extent of a delta-doped wire, which we find to be at
least 4.6 nm.Comment: 13 pages, 11 figure
A study of collider signatures for two Higgs doublet models with a Pseudoscalar mediator to Dark Matter
Two Higgs doublet models with an additional pseudoscalar particle coupling to
the Standard Model and to a new stable, neutral particle, provide an attractive
and fairly minimal route to solving the problem of Dark Matter. They have been
the subject of several searches at the LHC. We study the impact of existing LHC
measurements on such models, first in the benchmark regions addressed by
searches and then after relaxing some of their assumptions and broadening the
parameter ranges considered. In each case we study how the new parameters
change the potentially visible signatures at the LHC, and identify which of
these signatures should already have had a significant impact on existing
measurements. This allows us to set some first constraints on a number of so
far unstudied scenarios.Comment: 20 pages, 9 figures; added EW constraints contours, extended
explanation of WW model-dependency, extended motivation for pseudoscalar
mediators, corrected typo
High rate, fast timing Glass RPC for the high {\eta} CMS muon detectors
The HL-LHC phase is designed to increase by an order of magnitude the amount
of data to be collected by the LHC experiments. To achieve this goal in a
reasonable time scale the instantaneous luminosity would also increase by an
order of magnitude up to . The region of the forward
muon spectrometer () is not equipped with RPC stations. The
increase of the expected particles rate up to (including a
safety factor 3) motivates the installation of RPC chambers to guarantee
redundancy with the CSC chambers already present. The actual RPC technology of
CMS cannot sustain the expected background level. The new technology that will
be chosen should have a high rate capability and provides a good spatial and
timing resolution. A new generation of Glass-RPC (GRPC) using low-resistivity
(LR) glass is proposed to equip at least the two most far away of the four high
muon stations of CMS. First the design of small size prototypes and
studies of their performance in high-rate particles flux is presented. Then the
proposed designs for large size chambers and their fast-timing electronic
readout are examined and preliminary results are provided.Comment: 14 pages, 11 figures, Conference proceeding for the 2016 Resistive
Plate Chambers and Related Detector
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