Effects of Screening on Quark-Antiquark Cross Sections in Quark-Gluon Plasma

Lowest-order cross sections for qq̄ production and annihilation can be approximately corrected for higher-order QCD effects by using a corrective Kfactor. For energies where quark masses cannot be ignored, the K-factor is dominated by the wave function distortion arising from the initialor finalstate interaction between the quark and the antiquark. We evaluate this Kfactor for qq̄ production and annihilation in a quark-gluon plasma by taking into account the effects of Debye screening through a color-Yukawa potential. We present the corrective K-factor as a function of dimensionless parameters which may find applications in other systems involving attractive or repulsive Yukawa interactions. Prominent peaks of the K-factor occur for an attractive q-q̄ color-Yukawa interaction with Debye screening lengths of 0.835 and 3.23 times the Bohr radius, corresponding to two lowest s-wave qq̄ bound states moving into the continuum to become qq̄ resonances as the Debye screening length decreases. These resonances, especially the cc̄ and the bb̄ resonances, may be utilized to search for the quark-gluon plasma by studying the sys-