8,047 research outputs found
NLO corrections in MC event generator for angular distribution of Drell-Yan lepton pair production
Using a subtraction method, we derive the formulae suitable for use in
Monte-Carlo event generators to give the angular distribution for the
gluon-quark induced NLO corrections in Drell-Yan lepton pair production. We
also give the corresponding helicity density matrix for W and Z boson
production.Comment: 14 pages, 2 figure
Preliminary design approach for large high precision segmented reflectors
A simplified preliminary design capability for erectable precision segmented reflectors is presented. This design capability permits a rapid assessment of a wide range of reflector parameters as well as new structural concepts and materials. The preliminary design approach was applied to a range of precision reflectors from 10 meters to 100 meters in diameter while considering standard design drivers. The design drivers considered were: weight, fundamental frequency, launch packaging volume, part count, and on-orbit assembly time. For the range of parameters considered, on-orbit assembly time was identified as the major design driver. A family of modular panels is introduced which can significantly reduce the number of reflector parts and the on-orbit assembly time
Comparing Wilson and Clover Quenched Spectroscopy with an Improved Gauge Action
We present results of quenched hadron spectroscopy comparing
\order(a) improved Wilson (Clover) fermions with conventional Wilson
fermions. The configurations were generated using an \order(a^2) improved
6-link pure gauge action at 's corresponding to lattice spacings
of , , , , and fm. We find evidence that
fermionic scaling violations are consistent with \order(a^2) for Clover and
\order(a) with a nonnegligible \order(a^2) term for standard Wilson
fermions. This latter mixed ansatz makes a reliable continuum extrapolation
problematic for Wilson fermions. We also find that the slope of the scaling
violations is roughly for both Wilson and Clover fermions.Comment: 3 pages latex with 2 postscript figures. Talk presented at
LATTICE96(spectrum
Quenched hadron spectroscopy using improved fermionic and gauge actions
We present results of quenched hadron spectroscopy using \order(a)
improved Wilson fermions. The configurations were generated using an
\order(a^2) improved 6-link pure gauge action at 's
corresponding to lattice spacings of , , , , and
fm. We find evidence that fermionic scaling violations are consistent with
\order(a^2) errors.Comment: 4 pages latex with 3 postscript figures. Corrected column heading in
tabl
SCRI Results With the Tadpole-Improved Clover Action
We compare light hadron spectroscopy using the Wilson and Clover fermionic
actions. We show that a Clover coefficient chosen using tadpole-improved
tree-level perturbation theory effectively eliminates the O(a) discretization
errors present in the Wilson action. We find that discretization errors in
light spectroscopy for both the Wilson and Clover actions are characterized by
an energy scale mu of about 200-300 MeV, indicating that these errors can be
reduced to the 5% level by using the Clover action at an inverse lattice
spacing of about 1.3 GeV.Comment: Talk presented at the International Workshop on Lattice QCD On
Parallel Computers, University of Tsukuba, March 10-15 1997. 9 LaTex pages
plus 6 postscript figures, uses espcrc2.st
New-New Trade Policy
When national competitiveness is invoked as a policy objective, trade experts have learned to retort that countries don`t trade, firms do. This focus on the importance of the firm in international trade is consistent with the most recent developments in trade theory, but policy needs to catch up. Recognizing the growing anomalies in observed trade patterns relative to traditional models of trade based on national comparative advantage, the "new trade theory" of the 1980s looked at industries not countries, leading Nobel prize-winner Paul Krugman, a pioneer in this literature, to suggest the need for a new trade policy. Recent work on what some call the "new-new trade theory" focuses on the trading behaviour of individual firms, making a tight link between trade and productivity. In this paper we demonstrate how focusing on firms should be the foundation for a new-new trade policy, one that creates exciting opportunities for trade and investment promotion strategies, along with the need for much more targeted consultation strategies. We also discuss the implications of the new-new theory for regulatory coordination, and on new ways to cooperate with interlocutors in developing countries on the evolution of 21st century trade policy.New-new Trade Theory, Trade Policy
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