21 March 2022 to 30 September 2022
Europe/Zurich timezone

Are Jets Narrowed or Broadened in e+A SIDIS?

22 Mar 2022, 17:30
15m

Speaker

Will 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.

Primary author

Will Horowitz (University of Cape Town)

Co-authors

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

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