26-30 July 2021
Zoom
Europe/Berlin timezone

The Higgs field in brane-worlds

28 Jul 2021, 17:25
20m
Zoom

Zoom

Parallel session talk Quantum Field and String Theory T11: Quantum Field and String Theory

Speaker

Grégory Moreau (IJCLab, Université Paris-Saclay)

Description

The problematic huge hierarchy between the usual 4-dimensional Planck mass scale of gravity and the ElectroWeak symmetry breaking scale can interestingly disappear at some point-like location along extra space-like dimensions where the effective gravity scale is reduced down to the TeV scale. Field theories with point-like particle locations (3-dimensional brane-worlds) or point-like interactions deserve special care. In particular it can be shown that, in contrast with usual literature, brane-scalar fields – like the Standard Model Higgs boson – interacting with fermions in the whole space (bulk) do not need to be regularized if rigorous 4- or 5-dimensional treatments are applied: standard regularization introduces a finite width wave function for scalar fields localized along extra dimensions. The variational calculus of least action principle must also be applied strictly to derivate the fermion (Kaluza-Klein) masses and couplings, in particular by distinguishing the natural and essential boundary conditions: the higher-dimensional model – based in particular on extra compact spaces of type interval or circle (orbifold) – must be defined either completely through the action expression [necessity then for new specific brane terms bilinear in the fermion fields] or partially from additional so-called essential boundary conditions. Besides, the correct action integrand definition requires to introduce improper integrals in order to remain compatible with the fermion wave function discontinuities induced by point-like Higgs interactions. These presented new brane-Higgs treatments have phenomenological impacts and in particular the relaxing of previously obtained strong bounds on Kaluza-Klein masses, induced by flavour changing reactions generated through exchanges of the Higgs field.

Email moreau@ijclab.in2p3.fr
First author Grégory Moreau
Collaboration / Activity theoretical physicist

Primary author

Grégory Moreau (IJCLab, Université Paris-Saclay)

Co-authors

Dr Andrei Angelescu (Johannes Gutenberg-Universität Mainz) Dr Florian Nortier (Université Paris-Saclay ) Mr Ruifeng Leng (Université Paris-Saclay )

Presentation Materials