Theory Seminar (High Energy/Cosmology)

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Events During the Week of October 15th through October 22nd, 2023

Monday, October 16th, 2023

No events scheduled

Tuesday, October 17th, 2023

No events scheduled

Wednesday, October 18th, 2023

Extensions of a scale separation AdS$_4$ solution and their mass spectrum.
Time: 12:00 pm - 1:00 pm
Place: 5280 Chamberlin Hall
Speaker: Georgios Tringas , Annecy, LAPTH
Abstract: In this talk we will discuss two extensions of the so-called DGKT solution, a 4d scale-separated anti-de Sitter (AdS) solution obtained as a compactification on a 6d torus orbifold. Each extension consists in a specific large n expansion beyond the DGKT solution, where n is the unbounded F4-flux parameter. One of the extensions considered generalizes the known warped, partially localized solution. We analyse the two extensions in 10d massive type IIA supergravity as well as in a 4d effective theory, using a general warped compactification formalism. The main new correction to DGKT that we get is one from F4, the other fluxes being constrained by flux quantization. In each extension, one would expect corrections to the mass spectrum, before reaching contributions from alpha-prime corrections. However the mass spectrum turns out to be robust and conformal dimensions remain unchanged.
Host: Gary Shiu
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Thursday, October 19th, 2023

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Friday, October 20th, 2023

CP violating top-Higgs coupling in SMEFT
Time: 1:00 pm - 2:00 pm
Place: Chamberlin 5310
Speaker: Ya-Juan Zheng, Iwate U.
Abstract: The total cross section of the process mu- mu+ > vm vm~ ttH has strong dependence on the CP phase (xi) of the top Yukawa coupling, 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 gauge invariance is manifest, and find that the highest energy cross section is reduced to a quarter of the complex top Yukawa model result, with the same energy power. By applying the Goldstone boson (GB) equivalence theorem, we identied the origin of this strong energy growth of the SMEFT amplitudes as the contact dimension-6 pi-pi+ttH vertex, where pi^+- denotes the GB of W^+-. We obtain the Unitarity bound on the coecient of the SMEFT operator by using the optical theorem.
Host: Yoshihiko Abe
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