HET/HEE Seminar: Evan Johnson, April 13th

[Francis, Brian]

A friendly reminder for all, today at 11:30am in room M2035 we will hear from our very own Evan Johnson! In the High Energy seminar he'll speak on his work on EFTs for resonant wino dark matter. See you there!

Friday, April 13th, 2018
11:30am
M2035, Physics Research Building

Speaker: Evan Johnson
Title: Zero-Range Effective Field Theory for Resonant Wino Dark Matter
Dark matter in the form of weakly interacting massive particles (WIMPs) with masses at the TeV scale receive nonperturbative “Sommerfeld enhancements” to their pair annihilation rates due to unsuppressed exchanges of weak gauge bosons before the annihilation. These enhancements are conventionally computed numerically through the solution of coupled-channel Schrödinger equations. The most dramatic enhancements occur when there is an S-wave resonance near the WIMP-pair threshold. My collaborators and I have developed an effective field theory for wino dark matter near such a resonance. Winos interact nonperturbatively through zero-range contact interactions as well as through the long-range Coulomb interaction. Our analytic results for wino scattering and wino-pair annihilation accurately reproduce the results calculated numerically using the Schrödinger equation. I will show how this effective field theory is systematically improvable, how the Coulomb resummation is carried out, and how to build in the annihilation processes. Finally, I will demonstrate the power of this effective field theory by showing how a complicated process, the formation of a WIMP-pair bound state, can be calculated analytically.

-Brian
________________________________
From: Francis, Brian
Sent: Monday, April 09, 2018 11:32 AM
To: physics-all at lists.osu.edu
Subject: HET/HEE Seminar: Evan Johnson, April 13th

Hello all,

This week Friday we will be hosting our very own Evan Johnson for the High Energy seminar! Please join us and hear from Evan on his work with EFTs for resonant Wino dark matter! Please not this is no the typical time or room.

Friday, April 13th, 2018
11:30am
M2035, Physics Research Building

Speaker: Evan Johnson
Title: Zero-Range Effective Field Theory for Resonant Wino Dark Matter
Dark matter in the form of weakly interacting massive particles (WIMPs) with masses at the TeV scale receive nonperturbative “Sommerfeld enhancements” to their pair annihilation rates due to unsuppressed exchanges of weak gauge bosons before the annihilation. These enhancements are conventionally computed numerically through the solution of coupled-channel Schrödinger equations. The most dramatic enhancements occur when there is an S-wave resonance near the WIMP-pair threshold. My collaborators and I have developed an effective field theory for wino dark matter near such a resonance. Winos interact nonperturbatively through zero-range contact interactions as well as through the long-range Coulomb interaction. Our analytic results for wino scattering and wino-pair annihilation accurately reproduce the results calculated numerically using the Schrödinger equation. I will show how this effective field theory is systematically improvable, how the Coulomb resummation is carried out, and how to build in the annihilation processes. Finally, I will demonstrate the power of this effective field theory by showing how a complicated process, the formation of a WIMP-pair bound state, can be calculated analytically.

-Brian

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