8,432 research outputs found
A momentum Space Analysis of the Triple Pomeron Vertex in pQCD
We study properties of the momentum space Triple Pomeron Vertex in
perturbative QCD. Particular attention is given to the collinear limit where
transverse momenta on one side of the vertex are much larger than on the other
side. We also comment on the kernels in nonlinear evolution equations.Comment: Minor misprints corrected. To be published in EPJ
QCD Corrections to Electroweak Vector Boson Scattering at Small Scattering Angles
We investigate the role of a certain class of QCD corrections to electroweak
vector boson scattering at small scattering angles and large energies. These
are present since, from the perturbative analysis, the vector bosons may
dissociate into quark-antiquark pairs giving rise to colour dipoles interacting
through gluon exchanges. After the computation of the vector boson impact
factors, we present expressions for the lowest order QCD scattering amplitude
and for the leading logarithmic BFKL amplitude. Particularly we discuss
numerical results for the process . The QCD corrections to
the cross section resulting from the interference with the electroweak ones are
estimated and compared with the leading pure electroweak part. Corrections
resulting from the leading log BFKL amplitude are of the order of few percent
already at the TeV energy range.Comment: 21 pages,9 figures, discussion on the helicity-flip impact factors
added, typos correcte
The Pomeranchuk Singularity and Vector Boson Reggeization in Electroweak Theory
We investigate the high energy behaviour of vector boson scattering in the
electroweak sector of the standard model. In analogy with the BFKL analysis in
QCD we compute production amplitudes in the multi-Regge limit and derive, for
the vacuum exchange channel, the integral equation for vector particle
scattering. We also derive and solve the bootstrap equations for the isospin-1
exchange channel, both for the reggeizing charged and non-reggeizing neutral
vector bosons.Comment: 31 pages, 12 figures, 1 tabl
An Analytical Expression for the Non-Singlet Structure Functions at Small in the Double Logarithmic Approximation
A simple analytic expression for the non-singlet structure function
is given. The expression is derived from the result of Ref. [1] obtained by low
resummation of the quark ladder diagrams in the double logarithmic
approximation of perturbative QCD.Comment: 5 pages, A few comments and refs are adde
The new course at Muresk Agricultural College
THE original aim of all the agricultural colleges in Australia was to train young men to be farmers.
Over the years, and particularly in recent years, the colleges in the Eastern States found that less and less of their students were coming from the farming community, and a diminishing number were returning to farming
Performance Enhancement of the Flexible Transonic Truss-Braced Wing Aircraft Using Variable-Camber Continuous Trailing-Edge Flaps
Aircraft designers are to a growing extent using vehicle flexibility to optimize performance with objectives such as gust load alleviation and drag minimization. More complex aerodynamically optimized configurations may also require dynamic loads and perhaps eventually flutter suppression. This paper considers an aerodynamically optimized truss-braced wing aircraft designed for a Mach 0.745 cruise. The variable camber continuous trailing edge flap concept with a feedback control system is used to enhance aeroelastic stability. A linearized reduced order aerodynamic model is developed from unsteady Reynolds averaged Navier-Stokes simulations. A static output feedback controller is developed from that model. Closed-loop simulations using the reduced order aerodynamic model show that the controller is effective in stabilizing the vehicle dynamics
The Small-x Behaviour of the Singlet Polarized Structure Function g_2 in the Double Logarithmic Approximation
The small-x behavior of the singlet contributions to the polarized structure
function g_2(x,Q^2) is calculated in the double-logarithmic approximation of
perturbative QCD. The dominant contribution is due to the gluons which, in
contrast to the unpolarized case, mix with the fermions also in the small-x
domain. We find a power-like growth in 1/x in the odd-signature parts of the
amplitude with the same power as in the singlet function g_1(x,Q^2) at x<< 1.Comment: 20 pages, latex, 3 ps figure
The Dynamics of Spatial Labor Mobility in The Netherlands
The spatial mobility of labor changes over time. Both the general propensity to migrate and the spatial allocation of mobile people over regions of destination are characterized by important dynamic properties. This paper discusses several factors that may explain these dynamic properties of internal labor migration. We focus especially on the influence of labor market and housing conditions on the mobility of people. A two-stage, generation-allocation model is proposed, to investigate the role of different factors in the explanation of aggregate interregional migration flows. This model is applied to recent data on interprovincial labor migration in the Netherlands. The results indicate that housing supply seems to be an important determinant of temporal developments of spatial mobility, and also that the conditions of national and regional labor markets are associated with specific properties of recent migration patterns
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