15,462 research outputs found
Strong Isospin Breaking in CP-even and CP-odd K -> pi pi Decays
Complete next-to-leading (chiral) order (NLO) expressions for the strong
isospin-breaking (IB) contributions in K -> pi pi are used to discuss (1) for
CP-even, the impact on the magnitude of the Delta I=1/2 Rule, and (2) for
CP-odd, the strong IB correction, Omega_st, for the gluonic penguin
contribution to epsilon'/epsilon, with particular emphasis on the strong
low-energy constant (LEC) and loop contributions, numerical values for which
are model-independent at NLO.Comment: 4 pages. Contribution to the proceedings of the 7th Conference on the
Intersections of Particle and Nuclear Physics (CIPANP), May 22-28 2000,
Quebec City, Canada. Uses AIP 6x9 LaTeX styl
Isospin Breaking in the Extraction of Isovector and Isoscalar Spectral Functions from e^+e^- --> hadrons
A finite energy sum rule (FESR) analysis of the isospin-breaking vector
current correlator is used to determine the
isospin-breaking electromagnetic (EM) decay constants of the low-lying vector
mesons. These results are used to evaluate the corrections required to extract
the flavor diagonal 33 and 88 resonance contributions from the full resonance
EM contributions to the EM spectral function. A large (~15%) correction is
found in the case of the omega contribution to the isoscalar spectral function.
The implications of these results for sum rules based on the
isovector-isoscalar spectral difference are considered.Comment: Presentation to the 3rd International Conference on Symmetries in
Subatomic Physics, Adelaide, Mar. 13-17, 200
Legumes, Livestock and Livelihoods in the Australian Mixed Farming System
This Howard Oration describes the pathway that I have taken towards my specialisation in ‘big picture’ agriculture. A simple protocol is presented for the analysis of agricultural systems by using descriptive or quantitative indicators of five system properties: productivity, sustainability, profitability, social wellbeing and political acceptability. These properties are further illustrated by considering four important issues in the Australian sheep-wheat belt, a distinctive world food production system. The issues are the supply of and demand for legume nitrogen for crops, reconciling agricultural and natural resource objectives, the low profitability of farms in relation to production and marketing risks, and the conflict between enterprise specialisation (simplicity, scale) and diversification (complexity, resilience). Agricultural R&D has removed important technical constraints to progress in the sheep-wheat belt but insufficient attention has been paid to the economic and social issues embedded in this mixed farming system. I conclude that further progress will come from an integrated approach that encourages more effort on solving the social, economic and political issues in Australian agriculture, rather than a strict focus on agricultural productivity and sustainability
Monitoring and Evaluation of Research Activities in the Department of Agriculture, Thailand
ACNARP, in association with the Western Australian Department of Agriculture, received funds from AIDAB for a four-month consultancy input during 1989/90 to provide assistance to the Thai DOA in the development of efficient and effective methods and procedures for monitoring and evaluating agricultural research
Case-Building Behavior, Persistence, and Emergence Success of \u3ci\u3ePycnopsyche Guttifer\u3c/i\u3e (Walker) (Trichoptera: Limnephilidae) in Laboratory and \u3ci\u3ein situ\u3c/i\u3e Environments: Potential Trade-Offs of Material Preference
When removed from their cases in a non-flow laboratory environment, 5th instar Pycnopsyche guttifer (Walker) larvae were always successful in constructing a new case within 24 h when woody debris was present as a material choice. Most were successful within 1 h. Larvae were never successful at case building in the absence of wood in a non-flow environment. These laboratory-constructed ‘emergency cases’ were flimsy, lacking in shape, and larger than field cases. Laboratory case size, shape, and material preference remained constant after repeated daily evacuations over a series of 10 days. Larvae could be induced to construct a case composed of mineral particles only in the absence of wood and when placed in a laboratory stream with simulated flow conditions, or in situ in a natural stream. The emergence success of P. guttifer specimens induced to build these mineral cases, however, was significantly higher than that of larvae remaining in their field cases or of larvae that built wood cases. This result is likely due to a fungal infection that affected only larvae in wood cases. Our results demonstrate a scenario where a clearly non-preferred case construction material appears to increase survival
Asteroid flux and impact cratering rate on Venus
By the end of 1990, 65 Venus-crossing asteroids were recognized; these represent 59 percent of the known Earth-crossing asteroids. Further studies, chiefly numerical integrations of orbit evolution, may reveal one or two more Venus crossers among the set of discovered asteroids. A Venus crosser was defined as an asteroid whose orbit can intersect the orbit of Venus as a result of secular (long range) perturbations. Venus crossers revolving on orbits that currently overlap the orbit of Venus are called Venapol asteroids, and those on orbit that don't overlap are called Venamor asteroids; 42 Venapols and 23 Venamors were recognized. Collision probabilities with Venus for 60 of the known Venus crossers were determined
O(m_d-m_u) Effects in CP-even and CP-odd K-->pi pi Decays
Strong isospin-breaking (IB) effects in CP-even and CP-odd K-->pi pi decays are computed to next-to-leading order (NLO) in the chiral expansion. The impact of these corrections on the magnitude of the Delta I=1/2 Rule and on the size of the IB correction, Omega_IB, to the gluonic penguin contribution to epsilon'/epsilon are discussed
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