https://doi.org/10.1140/epjc/s10052-022-10386-x
Regular Article - Theoretical Physics
Jet broadening in the opacity and twist expansions
1
Department of Physics, University of Cape Town, 7701, Rondebosch, South Africa
2
Cavendish Laboratory, University of Cambridge, Cambridge, UK
3
New Mexico State University, 88011, Las Cruces, NM, USA
Received:
2
November
2021
Accepted:
2
May
2022
Published online:
12
May
2022
We compute the in-medium jet broadening 
to leading order in energy in the opacity expansion. At leading order in 
the elastic energy loss gives a jet broadening that grows with 
. The next-to-leading order in result is a jet narrowing, due to destructive LPM interference effects, that grows with 
. We find that in the opacity expansion the jet broadening asymptotics are – unlike for the mean energy loss – extremely sensitive to the correct treatment of the finite kinematics of the problem; integrating over all emitted gluon transverse momenta leads to a prediction of jet broadening rather than narrowing. We compare the asymptotics from the opacity expansion to a recent twist-4 derivation of and find a qualitative disagreement: the twist-4 derivation predicts a jet broadening rather than a narrowing. Comparison with current jet measurements cannot distinguish between the broadening or narrowing predictions. We comment on the origin of the difference between the opacity expansion and twist-4 results.
© The Author(s) 2022
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