25,801 research outputs found
Unique Mass Texture for Quarks and Leptons
Texture specific quark mass matrices which are hermitian and hierarchical are
examined in detail . In the case of texture 6 zeros matrices, out of sixteen
possibilities examined by us, none is able to fit the low energy data (LED),
for example, , ,
, lies in the range (PDG). Similarly none of the 32 texture 5 zeros mass matrices considered
is able to reproduce LED. In particular, the latest data from LEP regarding
rules out all of them. In the texture 4
zeros case, we find that there is a unique texture structure for and
mass matrices which is able to fit the data.Comment: 12 pages, LaTeX,some changes in the references,minor changes in the
text,to appear in Phys Rev D(Rapid communications
Flow and acoustic characteristics of subsonic and supersonic jets from convergent nozzle
Acoustic and flow characteristics of subsonic and supersonic jets from convergent nozzle
Spatio-temporal patterns of IED usage by the Provisional Irish Republican Army
In this paper, a unique dataset of improvised explosive device attacks during “The Troubles” in Northern Ireland (NI) is analysed via a Hawkes process model. It is found that this past dependent model is a good fit to improvised explosive device attacks yielding key insights about the nature of terrorism in NI. We also present a novel approach to quantitatively investigate some of the sociological theory surrounding the Provisional Irish Republican Army which challenges previously held assumptions concerning changes seen in the organisation. Finally, we extend our use of the Hawkes process model by considering a multidimensional version which permits both self and mutual-excitations. This allows us to test how the Provisional Irish Republican Army responded to past improvised explosive device attacks on different geographical scales from which we find evidence for the autonomy of the organisation over the six counties of NI and Belfast. By incorporating a second dataset concerning British Security Force (BSF) interventions, the multidimensional model allows us to test counter-terrorism (CT) operations in NI where we find subsequent increases in violence
Automated operation of a home made torque magnetometer using LabVIEW
In order to simplify and optimize the operation of our home made torque
magnetometer we created a new software system. The architecture is based on
parallel, independently running instrument handlers communicating with a main
control program. All programs are designed as command driven state machines
which greatly simplifies their maintenance and expansion. Moreover, as the main
program may receive commands not only from the user interface, but also from
other parallel running programs, an easy way of automation is achieved. A
program working through a text file containing a sequence of commands and
sending them to the main program suffices to automatically have the system
conduct a complex set of measurements. In this paper we describe the system's
architecture and its implementation in LabVIEW.Comment: 6 pages, 7 figures, submitted to Rev. Sci. Inst
An enterprise architecture driven approach to virtualisation
Organisations have shown a significant interest in the adoption of virtualisation technology for improving the efficiency of their Data Centres (DC) from both the resource performance and cost efficiency viewpoints. By improving the efficiency of data centres we can sustainably manage their impact on the environment by controlling their energy consumption. The intentions are clear but how best to approach to Data Centre virtualisation is not. This paper proposes an integrated Enterprise Architecture and Information Infrastructure (EAII) driven approach to guide the Data Centre virtualisation. The EAII approach has been developed based on the review and analysis of wellknown The Open Group Architecture Framework (TOGAF) and Information Infrastructure (II) model. The proposed integrated EAII approach seems appropriate to guide and align business strategy and virtualisation implementation for data centres of any size in any industry vertical
In Search of the Right Trousers Pattern - Comparison of Four Different Pattern Making Methods in Affordance with Different Body Shapes
Clothing comfort is one of the major concerns in the clothing industry. Various pattern making methods have been introduced to the industry with consideration to clothing comfort. This study evaluates four pattern making methods known as the ESMOD, Bunka, Aldrich, and Armstrong methods. The work focuses on trouser patterns and uses two subjects who have similar height, weight and BMI but have different body shapes and body sizes. The body measurement data of the two subjects were collected using a three-dimensional body scanner and patterns of the four different methods were developed accordingly. The fit of experimental garments were examined by two subjects and experts using questionnaires and were analysed
Damping of bulk excitations over an elongated BEC - the role of radial modes
We report the measurement of Beliaev damping of bulk excitations in cigar
shaped Bose Einstein condensates of atomic vapor. By using post selection,
excitation line shapes of the total population are compared with those of the
undamped excitations. We find that the damping depends on the initial
excitation energy of the decaying quasi particle, as well as on the excitation
momentum. We model the condensate as an infinite cylinder and calculate the
damping rates of the different radial modes. The derived damping rates are in
good agreement with the experimentally measured ones. The damping rates
strongly depend on the destructive interference between pathways for damping,
due to the quantum many-body nature of both excitation and damping products.Comment: 5 pages, 4 figure
The breaking of the flavour permutational symmetry: Mass textures and the CKM matrix
Different ansaetze for the breaking of the flavour permutational symmetry
according to S(3)L X S(3)R in S(2)L X S(2) give different Hermitian mass
matrices of the same modified Fritzsch type, which differ in the symmetry
breaking pattern. In this work we obtain a clear and precise indication on the
preferred symmetry breaking scheme from a fit of the predicted theoretical Vckm
to the experimentally determined absolute values of the elements of the CKM
matrix. The preferred scheme leads to simple mass textures and allows us to
compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner
angles of the unitarity triangle in terms of four quark mass ratios and only
one free parameter: the CP violating phase Phi. Excellent agreement with the
experimentally determined absolute values of the entries in the CKM matrix is
obtained for Phi = 90 deg. The corresponding computed values of the Jarlskog
invariant and the inner angles are J = 3.00 X 10^-5, alpha= 84 deg, beta= 24
deg and gamma =72 deg in very good agreement with current data on CP violation
in the neutral kaon-antikaon system and oscillations in the B-Bbar system.Comment: 21 pages, 1 fig. Content enlarged, references added and typos
corrected. To be published in Phys Rev
Causal Quantum Theory and the Collapse Locality Loophole
Causal quantum theory is an umbrella term for ordinary quantum theory
modified by two hypotheses: state vector reduction is a well-defined process,
and strict local causality applies. The first of these holds in some versions
of Copenhagen quantum theory and need not necessarily imply practically
testable deviations from ordinary quantum theory. The second implies that
measurement events which are spacelike separated have no non-local
correlations. To test this prediction, which sharply differs from standard
quantum theory, requires a precise theory of state vector reduction.
Formally speaking, any precise version of causal quantum theory defines a
local hidden variable theory. However, causal quantum theory is most naturally
seen as a variant of standard quantum theory. For that reason it seems a more
serious rival to standard quantum theory than local hidden variable models
relying on the locality or detector efficiency loopholes.
Some plausible versions of causal quantum theory are not refuted by any Bell
experiments to date, nor is it obvious that they are inconsistent with other
experiments. They evade refutation via a neglected loophole in Bell experiments
-- the {\it collapse locality loophole} -- which exists because of the possible
time lag between a particle entering a measuring device and a collapse taking
place. Fairly definitive tests of causal versus standard quantum theory could
be made by observing entangled particles separated by light
seconds.Comment: Discussion expanded; typos corrected; references adde
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