598 research outputs found
The Curci-Ferrari model with massive quarks at two loops
Massive quarks are included in the Curci-Ferrari model and the theory is
renormalized at two loops in the MSbar scheme in an arbitrary covariant gauge.Comment: 8 latex page
Perturbative Part of the Non-Singlet Structure Function F_2 in the Large-N_F Limit
We have calculated Wilson coefficients and anomalous dimensions
for the non-singlet part of the structure function F_2 in the large-N_F limit.
Our result agrees with exact two and three loop calculations and gives the
leading N_F dependence of the perturbative non-singlet Wilson coefficients to
all orders in .Comment: 11 pages, including one figur
Magnetic and chiral universality classes in a 3D Yukawa model
The 3D Yukawa model with U(1) chiral symmetry is investigated in a broad
interval of parameters using the Binder method. Critical exponents of the
Wilson-Fisher (magnetic) and Gross-Neveu (chiral) universality classes are
measured. The model is dominated by the chiral universality class. However at
weak coupling we observe a crossover between both classes, manifested by
difficulties with the Binder method which otherwise works well.Comment: 4 pages, contribution to LATTICE 9
Repeatability, Drift, and Aftereffect of Three Types of Aircraft Altimeters
In a series of laboratory tests of a number of sensitive altimeters 5 (Air Force type C-12 and C-13) and of precision altimeters (Air Force 8 type MA-1), the repeatability was determined for the full range of each type of instrument the drift characteristics were determined during 1-hour periods at various altitudes, and the drift and aftereffect were measured for a variety of simulated flights representative of some civil and military operations. For comparable altitude ranges, the repeatability errors of the C-12 and C-13 types were generally of the same order while those of the MA-1 type were somewhat smaller. The drift and aftereffect of the C-12 instruments were smaller than those of the C-13 instruments, and the drift and aftereffect of the MA-1 altimeters were considerably smaller than those of both types of the sensitive instruments. The drift of each of the three types of altimeters was found to increase with altitude and the drift of the precision type was found to increase with increasing rate of altitude change preceding the drift test
Two loop QCD vertices at the symmetric point
We compute the triple gluon, quark-gluon and ghost-gluon vertices of QCD at
the symmetric subtraction point at two loops in the MSbar scheme. In addition
we renormalize each of the three vertices in their respective momentum
subtraction schemes, MOMggg, MOMq and MOMh. The conversion functions of all the
wave functions, coupling constant and gauge parameter renormalization constants
of each of the schemes relative to MSbar are determined analytically. These are
then used to derive the three loop anomalous dimensions of the gluon, quark,
Faddeev-Popov ghost and gauge parameter as well as the beta-function in an
arbitrary linear covariant gauge for each MOM scheme. There is good agreement
of the latter with earlier Landau gauge numerical estimates of Chetyrkin and
Seidensticker.Comment: 36 latex pages, anc directory contains txt file with anomalous
dimensions, beta-functions, coupling constant mappings, conversion functions
and amplitudes in analytic for
Contract Report for The Science And Engineering Research Council. Contract Number Gr/F/06760. G.U. Aero Report 9201
This document constitutes the final report for SERC award No. GR/F/06760. It first
details the work programme of the original proposal made in 1987 and notes the work done to
illustrate completion and extensions beyond that proposed. For brevity, we confine the
technical discussion to the salient features of a particular aerofoil, albeit the work was an integral part of a larger programme on dynamic stall. The extent of this work may be gleaned from the accompanying enclosures representing some recent activity at Glasgow University.
Two of the main technical results from the present authors are worthy of note in that the
first (i.e. a correletion for incipient dynamic stall) has been used both in industry (VAWT Ltd) and research (under SERC GR/F/63466) to propose new aerofoil shapes for wind turbines. The second, however, (negative lift at large incidence during ramp-down motions from the stalled condition) has generated a new research activity (funded under SERC GR/H167U). This and future prospects are discussed prior to the concluding remarks. These remarks express the authors opinion of the success and overall value of the programme
Renormalization group aspects of the local composite operator method
We review the current status of the application of the local composite
operator technique to the condensation of dimension two operators in quantum
chromodynamics (QCD). We pay particular attention to the renormalization group
aspects of the formalism and the renormalization of QCD in various gauges.Comment: 13 latex pages, talk presented at RG0
Off-diagonal mass generation for Yang-Mills theories in the maximal Abelian gauge
We investigate a dynamical mass generation mechanism for the off-diagonal
gluons and ghosts in SU(N) Yang-Mills theories, quantized in the maximal
Abelian gauge. Such a mass can be seen as evidence for the Abelian dominance in
that gauge. It originates from the condensation of a mixed gluon-ghost operator
of mass dimension two, which lowers the vacuum energy. We construct an
effective potential for this operator by a combined use of the local composite
operators technique with algebraic renormalization and we discuss the gauge
parameter independence of the results. We also show that it is possible to
connect the vacuum energy, due to the mass dimension two condensate discussed
here, with the non-trivial vacuum energy originating from the condensate ,
which has attracted much attention in the Landau gauge.Comment: 15 pages. Revtex. 1 .eps figure. Talk given by D.Dudal at XXV
Encontro Nacional de Fisica de Particulas e Campos, Caxambu, Minas Gerais,
Brasil, 24-28 Aug 2004. To appear in Brazilian Journal of Physic
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