Tomáš Sýkora, Institute of Particle and Nuclear Physics, Charles University
Beyond its precision parton-structure program, ePIC's high inclusive luminosity, 4π hermeticity, and particle identification give direct access to non-perturbative and topological QCD processes in the final state. We develop one such case in detail with dedicated simulation and outline a second as a motivated future measurement.
The primary case is instanton-induced DIS — a chirality-violating, flavour-democratic process absent in perturbation theory. Using InstGen, a semiclassical instanton event generator whose deep-inelastic line we have adapted to ePIC's asymmetric beams (9 GeV e⁻ × 275 GeV p), we perform generator- and hadron-level studies with Pythia 8. At √s ≈ 100 GeV the accessible events are predominantly low-mass; the classic high-mass "fireball" is strongly rate-suppressed, and higher-energy running extends kinematic reach but does not recover it. The discriminating signatures nonetheless survive hadronization and separate cleanly from a perturbative baseline: enhanced strangeness (≈ 2×), high rest-frame isotropy (sphericity ≈ 0.6 vs ≈ 0.1), and elevated multiplicity. ePIC's luminosity and PID thus make it a precision instrument for characterizing this low-mass instanton regime rather than for high-mass discovery, with the trustworthy observables being shapes and flavour ratios rather than absolute rates.
We additionally note the baryon junction — a proposed gluonic, topological carrier of baryon number — as a complementary target whose clean observables (a slow, Regge-like net-baryon stopping slope, net-baryon/net-charge decoupling, and A-dependence) are well matched to ePIC's forward tagging and low-momentum baryon identification. As no current generator implements the junction mechanism, we present this as a measurement motivation and identify the simulation development it would require.