Jul 6 – 13, 2022
Bologna, Italy
Europe/Rome timezone

Are Jets Narrowed or Broadened in e+A SIDIS?

Jul 8, 2022, 3:40 PM
15m
Room 3 (Verde)

Room 3 (Verde)

Parallel Talk Heavy Ions Heavy Ions

Speaker

William Horowitz (University of Cape Town)

Description

We compute the in-medium jet broadening to leading order in energy in the opacity expansion. At leading order in $\alpha_s$ the elastic energy loss gives a jet broadening that grows with $\ln E$. The next-to-leading order in $\alpha_s$ result is a jet narrowing, due to destructive LPM interference effects, that grows with $\ln^2 E$. 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 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.

In-person participation No

Primary author

William Horowitz (University of Cape Town)

Co-authors

Prof. Matthew Sievert (New Mexico State University) Ms Hannah Clayton (Cambridge University)

Presentation materials