49 research outputs found
CompHEP 4.4 - Automatic Computations from Lagrangians to Events
We present a new version of the CompHEP program (version 4.4). We describe
shortly new issues implemented in this version, namely, simplification of quark
flavor combinatorics for the evaluation of hadronic processes, Les Houches
Accord based CompHEP-PYTHIA interface, processing the color configurations of
events, implementation of MSSM, symbolical and numerical batch modes, etc. We
discuss how the CompHEP program is used for preparing event generators for
various physical processes. We mention a few concrete physics examples for
CompHEP based generators prepared for the LHC and Tevatron.Comment: The paper has been presented on IX International Workshop on Advanced
Computing and Analysis Techniques in Physics Research December 1-5, 2003.
KEK, Japan. 10 pages, 2 figure
On impact parameter dependence of low-x structure functions
We consider impact parameter dependence of the polarized and unpolarized
structure functions. Unitarity does not allow factorization of the structure
functions over the Bjorken x and the impact parameter b variables. On the basis
of the particular geometrical model approach we conclude that spin of
constituent quark may have a significant orbital angular momentum component
which can manifest itself through the peripherality of the spin dependent
structure functions.Comment: 5 pages, 1 figur
Event Generators for WW Physics
The report summarizes the results of the activities of the Working Group on
Event Generators for WW Physics at CERN during 1995.Comment: 99 Latex, including 30 figures, 24 tables. The report is part of:
G.Altarelli,T.Sjostrand and F.Zwirner (eds), Physics at LEP2 CERN 96-0
Different behaviour of the spin structure functions and at
We consider low- behaviour of the spin structure functions and
in the unitarized chiral quark model which combines ideas on the
constituent quark structure of hadrons with a geometrical scattering picture
and unitarity. A nondiffractive singular low- dependence of and
indicated by the recent SMC experimental data is described. A
diffractive type smooth behaviour of is predicted at small . The
expectations for the double-spin asymmetries in the low-mass Drell-Yan
production at RHIC in the central region are discussed alongside.Comment: LaTeX, 10 pages, 2 figure
Application of Power Geometry and Normal Form Methods to the Study of Nonlinear ODEs
This paper describes power transformations of degenerate autonomous polynomial systems of ordinary differential equations which reduce such systems to a non-degenerative form. Example of creating exact first integrals of motion of some planar degenerate system in a closed form is given. © 2018 The Authors, published by EDP Sciences
Application of Power Geometry and Normal Form Methods to the Study of Nonlinear ODEs
This paper describes power transformations of degenerate autonomous polynomial systems of ordinary differential equations which reduce such systems to a non-degenerative form. Example of creating exact first integrals of motion of some planar degenerate system in a closed form is given. © 2018 The Authors, published by EDP Sciences