Importance of interactions in quark-gluon plasma: Baryon-number density contrast and primordial nucleosynthesis

We analyze the baryon-number density contrast $R$ between the quark-gluon-plasma (QGP) phase and the hadronic phase during a first-order quark-hadron phase transition in the early Universe. Without the inclusion of baryonic resonances in the hadronic phase, we can reduce $R$ by including interactions between quarks and gluons in the QGP phase. We also show that there is no need to use a large value of the bag constant to lower the value of $R$. Our calculations may be useful in non-standard big-bang nucleosynthesis.