Baryon Number Penetrability as a Measure of Isothermal Baryon Number Fluctuations in the Early Universe

We have examined the efficiency of baryon-number transport mechanism across the phase boundary in a cosmological quark-hadron phase transition through the proper estimate of baryon-number penetrability $<\Sigma_h>$. For this purpose we have derived first the double-pair creation probability $P_b$ in terms of single-pair creation probabilty per unit time and unit volume $\kappa_m$ and then obtained an analytical expression for $<\Sigma_h >$. Our calculation is free from the uncertainty of the value of double-pair creation probability per unit time and unit volume $\kappa_b$ which was used as a free parameter in earlier calculations. Finally the variations of double-pair creation probability $P_b$ as well as $<\Sigma_h>$ with temperature are shown and compared with other known results.