Moments.m is a Mathematica package which contains the analytical
results for the polarization functions \Pi^v and \Pi^s as defined in
Section 2 of the paper K.G. Chetyrkin, M. Steinhauser: "Heavy-light
current correlators at order $\alpha_s^2$ in QCD and HQET".  In the
low-energy limit terms up to order z^7 are included for the one- and
two-loop expressions and for the scalar three-loop correlator.  In the
vector case the three-loop results are contained up to order z^6.  In
the high-energy region the results are complete up to order 1/z^7.

The following variables are used
z   = q^2/M^2, where M is the on-shell quark mass
api = \alpha_s/\pi
mu  = \mu
cf  = (N_c^2-1)/2/Nc
ca  = N_c
tr  = 1/2
nl  = # massless quarks
nh  = 1 (massive quark)

More information on the defined functions can be obtained via the
Mathematica commands "?PiV*" and "?PiS*".
Example: the coefficient of order z^4 contributing to \Pi^{(2),s}_{FA}
is obtained via: Coefficient[ PiSsma , ca*cf*api^2*z^4 ]

Note: Moments.m has been updated on July 4, 2001.

	Name	Last modified	Size	Description
	Parent Directory		-
	HEADER.txt	2003-01-29 18:33	1.0K
	Moments.m	2003-01-29 18:33	37K