Jet broadening in the opacity and twist expansions
Publication Date
2022-05Journal Title
The European Physical Journal C
ISSN
1434-6044
Publisher
Springer Science and Business Media LLC
Volume
82
Issue
5
Language
en
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Clayton, H., Sievert, M. D., & Horowitz, W. (2022). Jet broadening in the opacity and twist expansions. The European Physical Journal C, 82 (5) https://doi.org/10.1140/epjc/s10052-022-10386-x
Description
Funder: South African National Research Foundation
Abstract
<jats:title>Abstract</jats:title><jats:p>We compute the in-medium jet broadening <jats:inline-formula><jats:alternatives><jats:tex-math>$$\langle p_\perp ^2\rangle $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mo>⟨</mml:mo>
<mml:msubsup>
<mml:mi>p</mml:mi>
<mml:mo>⊥</mml:mo>
<mml:mn>2</mml:mn>
</mml:msubsup>
<mml:mo>⟩</mml:mo>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> to leading order in energy in the opacity expansion. At leading order in <jats:inline-formula><jats:alternatives><jats:tex-math>$$\alpha _s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msub>
<mml:mi>α</mml:mi>
<mml:mi>s</mml:mi>
</mml:msub>
</mml:math></jats:alternatives></jats:inline-formula> the elastic energy loss gives a jet broadening that grows with <jats:inline-formula><jats:alternatives><jats:tex-math>$$\ln E$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mo>ln</mml:mo>
<mml:mi>E</mml:mi>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula>. The next-to-leading order in <jats:inline-formula><jats:alternatives><jats:tex-math>$$\alpha _s$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msub>
<mml:mi>α</mml:mi>
<mml:mi>s</mml:mi>
</mml:msub>
</mml:math></jats:alternatives></jats:inline-formula> result is a jet narrowing, due to destructive LPM interference effects, that grows with <jats:inline-formula><jats:alternatives><jats:tex-math>$$\ln ^2 E$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:msup>
<mml:mo>ln</mml:mo>
<mml:mn>2</mml:mn>
</mml:msup>
<mml:mi>E</mml:mi>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula>. 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 <jats:inline-formula><jats:alternatives><jats:tex-math>$$\langle p_\perp ^2\rangle $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mo>⟨</mml:mo>
<mml:msubsup>
<mml:mi>p</mml:mi>
<mml:mo>⊥</mml:mo>
<mml:mn>2</mml:mn>
</mml:msubsup>
<mml:mo>⟩</mml:mo>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> 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.</jats:p>
Keywords
Regular Article - Theoretical Physics
Identifiers
s10052-022-10386-x, 10386
External DOI: https://doi.org/10.1140/epjc/s10052-022-10386-x
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337132
Rights
Licence:
http://creativecommons.org/licenses/by/4.0/
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.
Recommended or similar items
The current recommendation prototype on the Apollo Repository will be turned off on 03 February 2023. Although the pilot has been fruitful for both parties, the service provider IKVA is focusing on horizon scanning products and so the recommender service can no longer be supported. We recognise the importance of recommender services in supporting research discovery and are evaluating offerings from other service providers. If you would like to offer feedback on this decision please contact us on: support@repository.cam.ac.uk