File:PhysRevC.100.024913.pdf

English: We compute the correction to the energy loss of a hard parton due to short separation distances between the creation of the particle and the in-medium scattering center that stimulates bremsstrahlung radiation to first order in opacity. In deriving the result we make full use of the large-formation-time assumption, which results in a significant reduction of the number of diagrams contributing to the small-separation-distance correction. An asymptotic analysis of our small-separation-distance correction term finds that the correction dominates at large ∼100 GeV parent parton energies, scales like L with the size of the system for small L but like L0 at larger L, and breaks color triviality. An extensive numerical investigation of the correction term confirms the aforementioned analytic findings, reveals that the correction term does not go to zero for large L, finds that the correction is sensitive to the mass of the parent parton, and shows a crucial dependence of the energy loss on a proper treatment of the physics of separation distances on the order of the Debye screening length. However, on examination, we have found the large-formation-time approximation to be invalid for much of the phase space of the emitted radiation, implying a need to investigate the sensitivity of jet quenching results from relaxing this approximation. Our result constitutes an important step toward understanding partonic energy loss in small colliding systems.