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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-8455
DTSTART:20231020T180000Z
DTEND:20231020T190000Z
DTSTAMP:20260404T032614Z
LAST-MODIFIED:20231013T004556Z
LOCATION:Chamberlin 5310
SUMMARY:CP violating top-Higgs coupling in SMEFT\, Theory Seminar (Hig
 h Energy/Cosmology)\, Ya-Juan Zheng\, Iwate U.
DESCRIPTION:The total cross section of the process mu- mu+ > vm vm~ tt
 H has strong dependence on the CP phase (xi) of the top Yukawa couplin
 g\, where the ratio of xi=pi and xi=0 (SM) grows to 630 at rts=30 TeV\
 , 3300 at 100 TeV. We study the cause of the strong energy dependence 
 and identied its origin as the (E/mW)2 growth of the weak boson fusion
  sub-amplitudes\, WL- WL+ > ttH\, when the two W's are longitudinally 
 polarized. We repeat the study in the SMEFT framework where the EW gau
 ge invariance is manifest\, and find that the highest energy cross sec
 tion is reduced to a quarter of the complex top Yukawa model result\, 
 with the same energy power. By applying the Goldstone boson (GB) equiv
 alence theorem\, we identied the origin of this strong energy growth o
 f the SMEFT amplitudes as the contact dimension-6 pi-pi+ttH vertex\, w
 here pi^+- denotes the GB of W^+-. We obtain the Unitarity bound on th
 e coecient of the SMEFT operator by using the optical theorem.
URL:https://www.physics.wisc.edu/events/?id=8455
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