13,435 research outputs found
Multiport VNA Measurements
This article presents some of the most recent multiport VNA measurement methodologies used to characterize these highspeed digital networks for signal integrity. There will be a discussion of the trends and measurement challenges of high-speed digital systems, followed by a presentation of the multiport VNA measurement system details, calibration, and measurement techniques, as well as some examples of interconnect device measurements. The intent here is to present some general concepts and trends for multiport VNA measurements as applied to computer system board-level interconnect structures, and not to promote any particular brand or produc
Quark-Lepton Symmetry In Five Dimensions
We construct a complete five dimensional Quark-Lepton symmetric model, with
all fields propagating in the bulk. The extra dimension forms an orbifold with the zero mode fermions corresponding to standard model
quarks localised at one fixed point. Zero modes corresponding to
left(right)-chiral leptons are localised at (near) the other fixed point. This
localisation pattern is motivated by the symmetries of the model. Shifting the
right-handed neutrinos and charged leptons slightly from the fixed point
provides a new mechanism for understanding the absence of relations of the type
or in Quark-Lepton symmetric models. Flavour changing
neutral currents resulting from Kaluza Klein gluon exchange, which typically
arise in the quark sector of split fermion models, are suppressed due to the
localisation of quarks at one point. The separation of quarks and leptons in
the compact extra dimension also acts to suppress the proton decay rate. This
permits the extra dimension to be much larger than that obtained in a previous
construct, with the bound TeV obtained.Comment: 12 pages, references added to match published versio
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UPC++ v1.0 Programmer’s Guide, Revision 2020.3.0
UPC++ is a C++11 library that provides Partitioned Global Address Space (PGAS) programming. It is designed for writing parallel programs that run efficiently and scale well on distributed-memory parallel computers. The PGAS model is single program, multiple-data (SPMD), with each separate constituent process having access to local memory as it would in C++. However, PGAS also provides access to a global address space, which is allocated in shared segments that are distributed over the processes. UPC++ provides numerous methods for accessing and using global memory. In UPC++, all operations that access remote memory are explicit, which encourages programmers to be aware of the cost of communication and data movement. Moreover, all remote-memory access operations are by default asynchronous, to enable programmers to write code that scales well even on hundreds of thousands of cores
Leptonic Flavor and CP Violation
We discuss how neutrino oscillation experiments can probe new sources of
leptonic flavor and CP violation.Comment: 8 pages, latex, no figures. Invited talk given at KAON 2001, Pisa,
Italy, June 12 - 17, 200
How to project a bipartite network?
The one-mode projecting is extensively used to compress the bipartite
networks. Since the one-mode projection is always less informative than the
bipartite representation, a proper weighting method is required to better
retain the original information. In this article, inspired by the network-based
resource-allocation dynamics, we raise a weighting method, which can be
directly applied in extracting the hidden information of networks, with
remarkably better performance than the widely used global ranking method as
well as collaborative filtering. This work not only provides a creditable
method in compressing bipartite networks, but also highlights a possible way
for the better solution of a long-standing challenge in modern information
science: How to do personal recommendation?Comment: 7 pages, 4 figure
CP Violation in \tau ->\nu\pi K_S and D->\pi K_S: The Importance of K_S-K_L Interference
The -factories have measured CP asymmetries in the and
modes. The state is identified by its decay to two pions at
a time that is close to the lifetime. Within the Standard Model and many
of its extensions, the asymmetries in these modes come from CP violation in
mixing. We emphasize that the interference between the
amplitudes of intermediate and is as important as the pure
amplitude. Consequently, the measured asymmetries depend on the times over
which the relevant decay rates are integrated and on features of the
experiment.Comment: 4 pages, 4 figure
Assortative mixing in networks
A network is said to show assortative mixing if the nodes in the network that
have many connections tend to be connected to other nodes with many
connections. We define a measure of assortative mixing for networks and use it
to show that social networks are often assortatively mixed, but that
technological and biological networks tend to be disassortative. We propose a
model of an assortative network, which we study both analytically and
numerically. Within the framework of this model we find that assortative
networks tend to percolate more easily than their disassortative counterparts
and that they are also more robust to vertex removal.Comment: 5 pages, 1 table, 1 figur
Optimization of robustness of scale-free network to random and targeted attacks
The scale-fee networks, having connectivity distribution (where is the site connectivity), is very resilient to random
failures but fragile to intentional attack. The purpose of this paper is to
find the network design guideline which can make the robustness of the network
to both random failures and intentional attack maximum while keeping the
average connectivity per node constant. We find that when $=3$ the
robustness of the scale-free networks reach its maximum value if the minimal
connectivity $m=1$, but when is larger than four, the networks will
become more robust to random failures and targeted attacks as the minimal
connectivity gets larger
New scalar resonances from sneutrino-Higgs mixing in supersymmetry with small lepton number (R-parity) violation
We consider new s-channel scalar exchanges in top quark and massive
gauge-bosons pair production in e+e- collisions, in supersymmetry with a small
lepton number violation. We show that a soft bilinear lepton number violating
term in the scalar potential which mixes the Higgs and the slepton fields can
give rise to a significant scalar resonance enhancement in e+e- -> ZZ, W+W- and
in e+e- -> t t(bar). The sneutrino-Higgs mixed state couples to the incoming
light leptons through its sneutrino component and to either the top quark or
the massive gauge bosons through its Higgs component. Such a scalar resonance
in these specific production channels cannot result from trilinear Yukawa-like
R-parity violation alone, and may, therefore, stand as strong evidence for the
existence of R-parity violating bilinears in the supersymmetric scalar
potential. We use the LEP2 measurements of the WW and ZZ cross-sections to
place useful constrains on this scenario, and investigate the expectations for
the sensitivity of a future linear collider to these signals. We find that
signals of these scalar resonances, in particular in top-pair production, are
well within the reach of linear colliders in the small lepton number violation
scenario.Comment: 22 pages in revtex, 10 figures embadded in the text using epsfi
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