High-pT Pion Quenching versus anti+Baryon Enhancement in Nucleus-Nucleus Collisions

Jet quenching of quarks and gluons in central A + A collisions suppresses the high-pT meson production and exposes novel baryon dynamics that we attribute to (gluonic) baryon junctions. This mechanism predicts baryon enhancement in a finite moderate-pT window that decreases with increasing impact parameter. We also extend recent calculations of the transverse momentum behavior of p/π and p̄/π to other baryon species and show that a similar pattern is expected for the K/Λ and K/Λ̄ ratios. Within the framework of the model constant p̄/p and Λ̄/Λ ratios are found in central Au+Au collisions at RHIC energies up to pT ≃ 4− 5 GeV.