Exotic Particle Production in Gamma Ray Burst Fireballs

We consider the possible production of stable lightest Kaluza-Klein particles (LKP) in baryonic gamma ray bursts (GRB) out flows. We numerically computed the energy-dependent cross-sections of Kaluza-Klein excitations for the Standard Model gauge bosons, $\gamma$ and $Z$. Next, we determine the feasibility of producing these KK excitations in gamma-ray emitting regions of GRBs. We find that a GRB fireball that accelerates baryons to energies greater than $10^{14}\rm eV$ could produce Kaluza-Klein excitations out to approximately $10^{12} \rm cm$, indicating that GRBs may be a significant source of the LKP. Finally, we explore the potential observational consequences of our results.