scholarly journals Constraints on Parton Density Functions from DØ

2008 ◽  
Author(s):  
Jonathan Hays
2010 ◽  
Author(s):  
Nataša Raičević ◽  
Angelos Angelopoulos ◽  
Takis Fildisis ◽  

2015 ◽  
Vol 37 ◽  
pp. 1560029 ◽  
Author(s):  
Frederik F. Van der Veken

Wilson lines are key objects in many QCD calculations. They are parallel transporters of the gauge field that can be used to render non-local operator products gauge invariant, which is especially useful for calculations concerning validation of factorization schemes and in calculations for constructing or modelling parton density functions. We develop an algorithm to express Wilson lines that are defined on piecewise linear paths in function of their Wilson segments, reducing the number of diagrams needed to be calculated. We show how different linear path topologies can be related using their color structure. This framework allows one to easily switch results between different Wilson line structures, which is helpful when testing different structures against each other, e.g. when checking universality properties of non-perturbative objects.


1995 ◽  
Vol 10 (20n21) ◽  
pp. 2901-2920 ◽  
Author(s):  
H. PLOTHOW-BESCH

This article describes an integrated package of Parton Density Functions called PDFLIB which has been added to the CERN Program Library Pool W999 and is labelled as W5051. In this package all the different sets of parton density functions of the Nucleon, the Pion and the Photon which are available today have been put together. All these sets have been combined in a consistent way such that they all have similar calling sequences and no external data files have to be read in anymore. A default set has been prepared, although those preferring their own set or wanting to test a new one may do so within the package. The package also offers a program to calculate the strong coupling constant αs to first or second order. The correct ΛQCD associated to the selected set of structure functions and the number of allowed flavours with respect to the given Q2 is automatically used in the calculation. The selection of sets, the program parameters as well as the possibilities to modify the defaults and to control errors occurred during execution are described.


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