4,332 research outputs found
Pure Leptonic Radiative Decays and the Annihilation Graph
Pure leptonic radiative decays of heavy-light mesons are calculated using a
very simple non-relativistic model. Dominant contribution originates from
photon emission from light initial quark. We find
and . The importance of these reactions to
clarify the dynamics of the annihilation graph is emphasized.Comment: 7 pages, LaTeX, 3 figure
Command Interneurons in the Crayfish Central Nervous System
The motor effects evoked by stimulation of each of eight command fibres in the circumoesophageal commissures of the crayfish are described. The fibres obtained appeared to have widespread connexions in all or most of the lower ganglia. For certain fibres the response was stronger on the homolateral side of the animal; for others it was symmetrical. The frequency of stimulation of a command fibre generally had a pronounced influence on the speed of the evoked response. In addition, segments of the total response could be elicited selectively by alteration of the frequency and duration of stimulation. Although the responses associated with most of the fibres were not sensitive to the fine temporal pattern of the applied stimulation, for one fibre the motor output depended clearly on the spacing of the stimulating pulses
CP Nonconservation in
CP violation effects in are examined. CP-odd,
-odd and -even observables can both be used to extract information on
the real and imaginary parts of Feynman amplitudes. Two Higgs doublet model
with CP violating phase from neutral Higgs exchange is used to estimate
possible effects.Comment: 9 pages, 4 Figures, Late
Increased Productivity of a Cover Crop Mixture Is Not Associated with Enhanced Agroecosystem Services
Cover crops provide a variety of important agroecological services within cropping systems. Typically these crops are grown as monocultures or simple graminoid-legume bicultures; however, ecological theory and empirical evidence suggest that agroecosystem services could be enhanced by growing cover crops in species-rich mixtures. We examined cover crop productivity, weed suppression, stability, and carryover effects to a subsequent cash crop in an experiment involving a five-species annual cover crop mixture and the component species grown as monocultures in SE New Hampshire, USA in 2011 and 2012. The mean land equivalent ratio (LER) for the mixture exceeded 1.0 in both years, indicating that the mixture over-yielded relative to the monocultures. Despite the apparent over-yielding in the mixture, we observed no enhancement in weed suppression, biomass stability, or productivity of a subsequent oat (Avena sativa L.) cash crop when compared to the best monoculture component crop. These data are some of the first to include application of the LER to an analysis of a cover crop mixture and contribute to the growing literature on the agroecological effects of cover crop diversity in cropping systems
Collaboration as a Medium for Effective Corporate Social Responsibility
Based on the qualitative research conducted with C-level executives this research proves that the three most predominant variables which determine a collaborations success are mutual trust, effective contractual practices, and a mutual understanding of common goals, values, and visions. By strongly implementing these into a collaboration, a partnership can amplify the end result of a collaborative effort and by using the concept of CSV as a source for alignment of mutual vision, a firm within a partnership can witness a multitude of different benefits to both their business and society
Bounds on charged higgs boson in the 2HDM type III from Tevatron
We consider the Two Higgs Doublet Model (2HDM) of type III which leads to
Flavour Changing Neutral Currents (FCNC) at tree level. In the framework of
this model we can use an appropriate form of the Yukawa Lagrangian that makes
the type II model limit of the general type III couplings apparent. This way is
useful in order to compare with the experimental data which is model dependent.
The analytical expressions of the partial width are
derived and we compare with the data available at this energy range. We examine
the limits on the new parameters from the validness of
perturbation theory.Comment: 14 pages, 4 figures, Universidad Nacional de Colombia. typos
correcte
Two body decays of the -quark: Applications to direct CP violation, searches for electro-weak penguins and new physics
A systematic experimental search for two-body hadronic decays of the b-quark
of the type b to quark + meson is proposed. These reactions have a well defined
experimental signature and they should be theoretically cleaner compared to
exclusive decays. Many modes have appreciable branching ratios and partial rate
asymmetries may also be quite large (about 8-50%) in several of them. In a few
cases electroweak penguins appear to be dominant and may be measurable. CP
violating triple correlation asymmetries provide a clean test of the Standard
Model.Comment: 12 pages 1 figure 1 tabl
Determination of optical technology experiments for a satellite
Optical technology experiments for satellite - communications, acquisition, tracking, lasers, photometry, and atmospheric
Transverse Tau Polarization in Decays of the Top and Bottom Quarks in the Weinberg Model of CP Non-conservation
We show that the transverse polarization asymmetry of the -lepton in
the decay is extremely sensitive to CP violating
phases arising from the charged Higgs exchange in the Weinberg model of CP
non-conservation. Qualitatively, the polarization asymmetries are enhanced over
rate or energy asymmetries by a factor of . Thus for optimal values of the parameters the method requires top pairs to be observable rather than needed for rate or energy
asymmetries. We also examine polarization in b decays via and find that it can also be very effective in constraining the CP
violation parameters of the extended Higgs sector.Comment: 11,1 figure, SLAC-PUB-608
CP Nonconservation in at the Tevatron
The reaction is found to be rather rich in exhibiting
several different types of CP asymmetries. The spin of the top quark plays an
important role. Asymmetries are related to form factors arising from radiative
corrections of the production vertex due to non-standard physics. As
illustrations, effects are studied in two Higgs Doublet Models and in
Supersymmetric Models; asymmetries up to a few percent may be possible.Comment: 14 pages, 3 figures. Note: replaced due to minor problems that
appeared on some postscript previewers. No change in conten
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