Radiative energy loss and p⊥-broadening of high energy partons in nuclei

TLDR

The study investigates medium‑induced transverse momentum broadening and gluon radiation of high‑energy partons traversing large nuclei. The authors model parton multiple scattering in the nucleus using the Glauber approximation. They find that radiative energy loss per unit length and transverse momentum broadening both increase linearly with nuclear length, with dE/dz = (1/8) α_s N_c p⊥W² independent of scattering details, and that these effects are stronger in hot matter, offering a potential quark‑gluon plasma signal.

Abstract

The medium-induced $p_{\perp}$-broadening and induced gluon radiation spectrum of a high energy quark or gluon traversing a large nucleus is studied. Multiple scattering of the high energy parton in the nucleus is treated in the Glauber approximation. We show that -dE/dz, the radiative energy loss of the parton per unit length, grows as L, the length of the nuclear matter, as does the characteristic transverse momentum squared of the parton $p_{\perp W}^2$. We find dE/dz = (1/8)\alpha_s N_c $p_{\perp W}^2$ holds independent of the details of the parton-nucleon scatterings so long as L is large. Numerical estimates suggest that $p_{\perp}$-broadening and energy loss may be significantly enhanced in hot matter as compared to cold matter, thus making the study of such quantities a possible signal for quark-gluon plasma formation.