2,311 research outputs found
HECTOR 1.00 - A program for the calculation of QED, QCD and electroweak corrections to ep and lN deep inelastic neutral and charged current scattering
A description of the Fortran program HECTOR for a variety of semi-analytical
calculations of radiative QED, QCD, and electroweak corrections to the
double-differential cross sections of NC and CC deep inelastic charged lepton
proton (or lepton deuteron) scattering is presented. HECTOR originates from the
substantially improved and extended earlier programs HELIOS and TERAD91. It is
mainly intended for applications at HERA or LEPxLHC, but may be used also for
muon scattering in fixed target experiments. The QED corrections may be
calculated in different sets of variables: leptonic, hadronic, mixed,
Jaquet-Blondel, double angle etc. Besides the leading logarithmic approximation
up to order O(alpha^2), exact order O(alpha) corrections and inclusive soft
photon exponentiation are taken into account. The photoproduction region is
also covered.Comment: 74 pages, LaTex, 14 figures, 7 tables, a uuencoded file containing
the latex file and figures is available from: http://www.ifh.de/theory/ or on
request from e-mail: [email protected]
Exponentiation for products of Wilson lines within the generating function approach
We present the generating function approach to the perturbative
exponentiation of correlators of a product of Wilson lines and loops. The
exponentiated expression is presented in closed form as an algebraic function
of correlators of known operators, which can be seen as a generating function
for web diagrams. The expression is naturally split onto two parts: the
exponentiation kernel, which accumulates all non-trivial information about web
diagrams, and the defect of exponentiation, which reconstructs the matrix
exponent and is a function of the exponentiation kernel. The detailed
comparison of the presented approach with existing approaches to exponentiation
is presented as well. We also give examples of calculations within the
generating function exponentiation, namely, we consider different
configurations of light-like Wilson lines in the multi-gluon-exchange-webs
(MGEW) approximation. Within this approximation the corresponding correlators
can be calculated exactly at any order of perturbative expansion by only
algebraic manipulations. The MGEW approximation shows violation of the dipole
formula for infrared singularities at three-loop order.Comment: 33 pages, 5 figures; updated to match journal versio
Normal Elliptic Bases and Torus-Based Cryptography
We consider representations of algebraic tori over finite fields.
We make use of normal elliptic bases to show that, for infinitely many
squarefree integers and infinitely many values of , we can encode
torus elements, to a small fixed overhead and to -tuples of
elements, in quasi-linear time in .
This improves upon previously known algorithms, which all have a
quasi-quadratic complexity. As a result, the cost of the encoding phase is now
negligible in Diffie-Hellman cryptographic schemes
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