t-t-h, Top & Bottom Partners,
and the Brane Higgs Limit
Manuel Toharia
Abstract Higgs boson production in association with top quarks (tth) is one of the
most interesting Higgs production mechanisms, as it probes the top quark Yukawa
coupling. The ATLAS experiment announced a combined observed significance
of 6.3 sigma for this process along with a combined expected significance of 5.1
sigma (both relative to the background-only hypothesis) (Aaboud et al. [ATLAS],
Phys Lett B 784:173–191, 2018). The CMS experiment announced a combined
observed significance of 5.2 sigma with a combined expected significance of 4.2
sigma (Sirunyan et al. (CMS Collaboration), Phys Rev Lett 120:23180, 2018). We
explore the possibility of deviations in Higgs Yukawa couplings that might lead to
enhancements in tth production, within models with vector-like partners of the top
and bottom quarks, with masses of order 1–2 TeV. In a certain limit of parameter
space, Higgs production through gluon fusion can remain under control even with
large deviations of the top quark Yukawa coupling. We call this scenario the “Brane
Higgs Limit”, as it can emerge naturally in models of warped extra-dimensions with
all matter fields in the bulk (except the Higgs). The scenario is predictive and easily
falsifiable for all Higgs production and decay modes.
Keywords Collider physics · Higgs boson · Warped extra-dimensions
1 Introduction
RUN 1 of the LHC culminated in the discovery of a new particle consistent with the
Standard Model (SM) Higgs boson with a mass of 125 GeV. Extensions to the SM
could manifest themselves indirectly within the Higgs sector, and in particular they
could affect the production cross section and decay rates of the Higgs boson. After
M. Toharia ()
Dawson College, Montreal, QC, Canada
e-mail: mtoharia@dawsoncollege.qc.ca
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_56
599
and the Brane Higgs Limit
Manuel Toharia
Abstract Higgs boson production in association with top quarks (tth) is one of the
most interesting Higgs production mechanisms, as it probes the top quark Yukawa
coupling. The ATLAS experiment announced a combined observed significance
of 6.3 sigma for this process along with a combined expected significance of 5.1
sigma (both relative to the background-only hypothesis) (Aaboud et al. [ATLAS],
Phys Lett B 784:173–191, 2018). The CMS experiment announced a combined
observed significance of 5.2 sigma with a combined expected significance of 4.2
sigma (Sirunyan et al. (CMS Collaboration), Phys Rev Lett 120:23180, 2018). We
explore the possibility of deviations in Higgs Yukawa couplings that might lead to
enhancements in tth production, within models with vector-like partners of the top
and bottom quarks, with masses of order 1–2 TeV. In a certain limit of parameter
space, Higgs production through gluon fusion can remain under control even with
large deviations of the top quark Yukawa coupling. We call this scenario the “Brane
Higgs Limit”, as it can emerge naturally in models of warped extra-dimensions with
all matter fields in the bulk (except the Higgs). The scenario is predictive and easily
falsifiable for all Higgs production and decay modes.
Keywords Collider physics · Higgs boson · Warped extra-dimensions
1 Introduction
RUN 1 of the LHC culminated in the discovery of a new particle consistent with the
Standard Model (SM) Higgs boson with a mass of 125 GeV. Extensions to the SM
could manifest themselves indirectly within the Higgs sector, and in particular they
could affect the production cross section and decay rates of the Higgs boson. After
M. Toharia ()
Dawson College, Montreal, QC, Canada
e-mail: mtoharia@dawsoncollege.qc.ca
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_56
599