Transverse momentum broadening in semi-inclusive deep inelastic scattering at next-to-leading order

Abstract

Within the framework of higher-twist collinear factorization, transverse momentum broadening for the final hadrons in semi-inclusive deeply inelastic e + A collisions is studied at the next-to-leading order (NLO) in perturbative QCD. Through explicit calculations of real and virtual corrections at twist-4, the transverse-momentum-weighted differential cross section due to double scattering is shown to factorize at NLO and can be expressed as a convolution of twist-4 nuclear parton correlation functions, the usual twist-2 fragmentation functions and hard parts which are finite and free of any divergences. A QCD evolution equation is also derived for the renormalized twist-4 quarkgluon correlation function which can be applied to future phenomenological studies of transverse momentum broadening and jet quenching at NLO.

Revisiting heavy quark radiative energy loss in nuclei within the high-twist approach

“…[17] by setting the same transverse momentum for the rescattered gluons from the nucleus. This setting has been shown to be valid, in the case of light hadron production, for symmetric double scattering subprocesses, such as hard-hard and soft-soft double scatterings [20]. We have verified explicitly that this statement also holds for heavy flavor meson production.…”

“…Following the same logic, one can assign initial state parton momenta k 1 = xp + k 2T − k 3T , k 2 = x 1 p, k g = x 3 p + k 3T and k g = x 2 p + k 2T in the process of hard-soft double scattering. The final result can be obtained from the soft-hard double scattering via the replacement e −i( (20). Thus the difference to Ref.…”

Radiative corrections to the jet quenching parameter in dilute and dense media

“…In going from the first to the second lines of Eq. (19) it has been recognized that the main contribution to the integration comes from the region where |Ωτ | is small. More precisely, the relevant region is limited by the condition τ ω/q which is the typical branching time for the emission of a gluon with energy ω.…”

Jet-medium interactions at NLO in a weakly-coupled quark-gluon plasma

“…Some authors have used the term NLO in a different sense: for instance that the initial parton producing processes or the final fragmentation processes are treated at NLO, though the medium interactions are still leading order[13,14], or within the Higher Twist formalism[15,16], or that higher-order, doublelogarithmic corrections to the jet-quenching parameter are considered and resummed[17][18][19]. Here by NLO we mean a beyond-leading-order treatment of the way the jet interacts with the medium.…”