The cross section for the production of particle C in a collision of hadron A and hadron B, , can be factorized into three part:
Similarly, the polarization dependent cross section can be described as
The polarization dependent cross section has been calculated in leading order (LO) [11,12] and listed in Table iii. If we choose the process which is free from fragmentation such as high prompt photon production, weak boson production (leptonic decay mode), the experimentally measured asymmetry can be directly connected to the products of two structure functions and . In the case we know one of the polarized structure functions, say , we can determine from the measurement.
Table iii: Parton cross sections and asymmetries. Each entry multiplies a
factor of , except for the first (Drell-Yan)
which multiplies , and the last (prompt
production) which multiplies
.
In addition, helicity entries multiply according to whether the
beam helicities are equal (+1) or opposite (-1), and
transversity entries
multiply the kinematic factor ,
which is proportional
to in the parton-parton center of mass frame.
Figure 3: Asymmetries for the partonic processes,
and are plotted as functions of
the cosine of the scattering angle in the center-of-mass
system of interacting partons.