46,433 research outputs found
Profiles of the Unitarity Triangle and CP-Violating Phases in the Standard Model and Supersymmetric Theories
We report on a comparative study of the profile of the CKM unitarity
triangle, and the resulting CP asymmetries in B decays, in the standard model
and in several variants of the minimal supersymmetric standard model (MSSM),
characterized by a single phase in the quark flavour mixing matrix. The
supersymmetric contributions to the mass differences \Delta M_d, \Delta M_s and
to the CP-violating quantity |\epsilon| are, to an excellent approximation,
equal to each other in these theories, allowing for a particularly simple way
of implementing the resulting constraints on the elements of V_{CKM} from the
present knowledge of these quantities. Incorporating the next-to-leading-order
corrections and applying the current direct and indirect constraints on the
supersymmetric parameters, we find that the predicted ranges of \sin 2 \beta in
the standard model and in MSSM models are very similar. However, precise
measurements at B-factories and hadron machines may be able to distinguish
these theories in terms of the other two CP-violating phases \alpha and \gamma.
This is illustrated for some representative values of the supersymmetric
contributions in \Delta M_d, \Delta M_s and |\epsilon|.Comment: 30 pages, 9 figures; typos corrected, minor notation change; matches
version to appear in the European Physical Journal
Effects of heavy Majorana neutrinos at lepton-proton colliders
We discuss the prospects of detecting the processes
and
() under the conditions of the present collider
HERA and of future colliders. These high-energy processes are assumed to be
mediated by the exchange of heavy Majorana neutrinos (HMN). We consider two
simple scenarios for the HMN mass spectrum: the effective singlet () and the effective doublet (). For the latter
case, the cross section includes information about CP-violating phases.Comment: 5pages, 2 figures; published in conference proceedings: Particle
Physics in Laboratory, Space and Universe, 11th. Lomonosov Conf. on
Elementary Particle Physics (Moscow, 21-27 August 2003) (Singapore, World
Scientific, 2005
Electron angular correlation in neutrinoless double beta decay and new physics
The angular correlation of the electrons in the neutrinoless double beta
decay () is calculated taking into account the nucleon recoil, the
and -waves for the electrons and the electron mass using a general
Lorentz invariant effective Lagrangian. We show that the angular coefficient is
essentially independent of the nuclear matrix element models. We work out the
angular coefficient in several scenarios for new physics, in particular, in the
left-right symmetric models.Comment: 5 pages, 1 figure; to appear in the Proceedings of the 13th Lomonosov
Conference on Elementary Particle Physics, 23 --29 August 2007, Moscow,
Russi
Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation
Assuming the dominance of the spin-spin interaction in a diquark, we point
out that the mass difference in the beauty sector M(Z_b^prime) - M(Z_b) scales
with quark masses as expected in QCD, with respect to the corresponding mass
difference M(Z_c^prime) - M(Z_c). Notably, we show that the decays
Upsilon(10890) --> Upsilon(nS) pi pi and Upsilon(10890) --> (h_b(1P), h_b(2P))
pi pi are compatible with heavy-quark spin conservation if the contributions of
Z_b,Z_b^prime intermediate states are taken into account, Upsilon(10890) being
either a Upsilon(5S) or the beauty analog of Y_c(4260). Belle results on these
decays support the quark spin wave-function of the Z states as tetraquarks. We
also consider the role of light quark spin non-conservaton in Z_b,Z_b^prime
decays into B B^* and B^* B^*. Indications of possible signatures of the still
missing X_b resonance are proposed.Comment: 5 pages, comments added, to appear in Phys Rev
Space processing of chalcogenide glasses
Chalcogenide glasses are discussed as good infrared transmitters, possessing the strength, corrosion resistance, and scale-up potential necessary for large 10.6-micron windows. The disadvantage of earth-produced chalcogenide glasses is shown to be an infrared absorption coefficient which is unacceptably high relative to alkali halides. This coefficient is traced to optical nonhomogeneities resulting from environmental and container contamination. Space processing is considered as a means of improving the infrared transmission quality of chalcogenides and of eliminating the following problems: optical inhomogeneities caused by thermal currents and density fluctuation in the l-g earth environment; contamination from the earth-melting crucible by oxygen and other elements deleterious to infrared transmission; and, heterogeneous nucleation at the earth-melting crucible-glass interface
Production, Competition Indices, and Nutritive Values of Setaria Splendida, Centrosema Pubescens, and Clitoria Ternatea in Mixed Cropping Systems in Peatland
This research was conducted to evaluate production, different competition indices and nutritive value of Setaria splendida, Centrosema pubescens, and Clitoria ternatea in monoculture and mix cropping system on peat soil land. The experiment was set up in a randomized complete block design with five treatments and three replications. The five treatments were: S. splendida sole cropping (SS), C. pubescens sole cropping (CP), C. ternatea sole cropping (CT), S. splendida and C. pubescens mix cropping (SS/CP) and S. splendida/C. ternatea mix cropping (SS/CT). The DM yield of S. splendida in mixed cropping with C. pubescens increased 43.4% and in mix cropping with C. ternatea increased 15.7% compared to sole S. splendida. The value of land equivalent ratio of SS/CP (LERSS/CP) was >1. The LERSS/CT value was <1. The crowding coefficient value of S. splendida (KSS) was higher than KCP and KCT. The total value of KSS/CP and KSS/CT were >1. The competition ratio (CR) values of S. splendida in both mix cropping were >1. The agressivity (A) values of S. splendida in both mix cropping were positive. The crude protein, NDF and ADF content of forage were not affected by mix cropping system. In conclusion, mix cropping in peatland do not affect productivity and nutritive value of S. splendida, C. pubescens, and C. ternatea. S. splendida is more effective in exploiting environmental resources when intercropped with C. pubescens compared to C. ternatea on peatland
Video vehicle detection at signalised junctions: a simulation-based study
Many existing advanced methods of traffic signal control depend on information about
approaching traffic provided by inductive loop detectors at particular points in the road. But
analysis of images from CCTV cameras can in principle provide more comprehensive
information about traffic approaching and passing through junctions, and cameras may be
easier to install and maintain than loop detectors, and some systems based on video detection
have already been in use for some time.
Against this background, computer simulation has been used to explore the potential of
existing and immediately foreseeable capability in automatic on-line image analysis to extract
information relevant to signal control from images provided by cameras mounted in
acceptable positions at signal-controlled junctions. Some consequences of extracting relevant
information in different ways were investigated in the context of an existing detailed
simulation model of vehicular traffic moving through junctions under traffic-responsive signal
control, and the development of one basic and one advanced algorithm for traffic-responsive
control. The work was confined as a first step to operation of one very simple signalcontrolled
junction.
Two techniques for extraction of information from images were modelled - a more ambitious
technique based on distinguishing most of the individual vehicles visible to the camera, and a
more modest technique requiring only that the presence of vehicles in any part of the image
be distinguished from the background scene. In the latter case, statistical modelling was used
to estimate the number of vehicles corresponding to any single area of the image that
represents vehicles rather than background.
At the simple modelled junction, each technique of extraction enabled each of the algorithms
for traffic-responsive control of the signals to achieve average delays per vehicle appreciably
lower than those given by System D control, and possibly competitive with those that MOVA
would give, but comparison with MOVA was beyond the scope of the initial study.
These results of simulation indicate that image analysis of CCTV pictures should be able to
provide sufficient information in practice for traffic-responsive control that is competitive
with existing techniques. Ways in which the work could be taken further were discussed with
practitioners, but have not yet been progressed
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