From Lead to Helium: Discovery Potential for Jet Quenching in the Smallest Collision Systems

Abstract

We present perturbative quantum chromodynamics (pQCD) predictions for the modification to the yield of high-momentum particles in very light ion collisions - ${}^{10}\mathrm{B}+{}^{10}\mathrm{B}$, ${}^6\mathrm{Li}+{}^6\mathrm{Li}$, ${}^4\mathrm{He}+{}^4\mathrm{He}$, and ${}^3\mathrm{He}+{}^3\mathrm{He}$ - both with and without medium-induced energy loss. We show that there is non-trivial suppression expected from our partonic energy loss model in symmetric systems from ${}^{208}\mathrm{Pb}+{}^{208}\mathrm{Pb}$ to ${}^3\mathrm{He}+{}^3\mathrm{He}$ and in asymmetric systems $A+B$, and that the energy loss scales approximately with $(\sqrt{AB}{)}^{1/3}$. Further, we find that deep inelastic scattering measurements in ${}^3\mathrm{He}$ and ${}^6\mathrm{Li}$ tightly constrain the nPDF baseline, making these isotopes a particularly clean environment for observing final-state partonic energy loss induced by the formation of a quark-gluon plasma in these very small systems.

7 pages, 2 figures