Program "xCOLOR". User's Manual.
--------------------------------
A.Kryukov
Institute for Nuclear Physics
Moscow State University
119899, Moscow, RUSSIA
E-mail: kryukov@npi.msu.su
Phone/Fax: (095) 939-0397
Abstract
Program "xCOLOR" is intended for calculation the colour
factor in non-abelian gauge field theories. It is
realized Cvitanovich algorithm [1]. In comparision with
"COLOR" program [2] it was made many improvements. The
package was writen by symbolic mode. This version is
faster then [2] more then 10 times.
After load the program by the following command
load xcolor;
user can be able to use the next additional commands and operators.
Command SUdim.
--------------
Format: SUdim <any expression>;
Set the order of SU group.
The default value is 3, i.e. SU(3).
Command SpTT.
-------------
Format: SpTT <any expression>;
Set the normalization coefficient A: Sp(TiTj) = A*Delta(i,j).
Default value is 1/2.
Operator QG.
------------
Format: QG(inQuark,outQuark,Gluon)
Describe the quark-gluon vertex. Parameters may be any identifiers.
First and second of then must be in- and out- quarks correspondently.
Third one is a gluon.
Operator G3.
------------
Format: G3(Gluon1,Gluon2,Gluon3)
Describe the three-gluon vertex. Parameters may be any identifiers.
The order of gluons must be clock.
In terms of QG and G3 operators you input diagram in "color" space as
a product of these operators. For example.
Diagram: REDUCE expression:
e1
---->---
/ \
| e2 |
v1*..........*v2 <===> QG(e3,e1,e2)*QG(e1,e3,e2)
| |
\ e3 /
----<---
Here: --->--- quark
....... gluon
More detail see [2].
References.
-----------
[1] P.Cvitanovic, Phys. Rev. D14(1976), p.1536.
[2] A.Kryukov & A.Rodionov, Comp. Phys. Comm., 48(1988), pp.327-334.
Any remarks send to
A.Kryukov
Institute for Nuclear Physics
Moscow State University
119899, Moscow, RUSSIA
E-mail: kryukov@npi.msu.su
Phone/Fax: (095) 939-0397
Good luck!