Related papers: The Elusive Gluon
Composite Higgs models predict the existence of resonances. We study in detail the collider phenomenology of both the vector and fermionic resonances, including the possibility of both of them being light and within the reach of the LHC. We…
Naturalness demands that the quadratic divergence of the one-loop top contribution to the Higgs mass be cancelled at a scale below 1 TeV. This can be achieved by introducing a fermionic (spin-1/2) top partner, as in, for example, Little…
Many models of Beyond the Standard Model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In…
In this project we study the phenomenology of models where the Higgs is a bound state of a strongly interacting dynamics at the TeV scale and we assess the LHC potential to discover new heavy colored states. In the first part of the thesis…
Within the context of composite Higgs models, recent hints on lepton-flavour non-universality in $B$ decays can be explained by a vector resonance $V$ with sizeable couplings to the Standard Model leptons ($\ell$). We argue that, in such a…
We perform a study of the LHC discovery reach on a heavy gluon (G*) and heavy fermions (top and bottom excitations), coming from a new composite sector. We find that heavy fermion resonances have a great impact on the composite gluon…
Composite Higgs models, where the Higgs boson is identified with the pseudo-Nambu-Goldstone-Boson (pNGB) of a strong sector, typically have light composite fermions (top partners) to account for a light Higgs. This type of models…
A search for heavy resonances decaying to a Higgs boson and a vector boson is presented. The analysis is performed using data samples collected in 2015 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy…
Many standard model extensions, including composite Goldstone Higgs models, predict vector-like fermionic top-partners at the TeV scale. The intensive search programmes by ATLAS and CMS focus on decays into a 3$^{\rm rd}$ generation quark…
A search is presented for a heavy vector resonance decaying into a Z boson and the standard model Higgs boson, where the Z boson is identified through its leptonic decays to electrons, muons, or neutrinos, and the Higgs boson is identified…
We introduce a simplified low-energy effective Lagrangian description of the phenomenology of heavy vector resonances in the minimal composite Higgs model, based on the coset SO(5)/SO(4), analysing in detail their interaction with lighter…
Fermionic top-partners arise in models such as Composite Higgs and Little Higgs. They modify Higgs properties, in particular how the Higgs couples to top quarks. Alas, there is a low-energy cancellation acting in the coupling of the Higgs…
A search for heavy resonances, decaying into the standard model vector bosons and the standard model Higgs boson, is presented. The final states considered contain a b quark-antiquark pair from the decay of the Higgs boson, along with…
We have analysed the observable consequences of the interactions of spin-1 resonances coupled to the invariant fermionic currents that arise in an $SO(5)$ Composite Higgs set-up. The phenomenology entailed by such interactions is thoroughly…
We investigate the implications of models that achieve a Standard Model-like Higgs boson of mass near 125 GeV by introducing additional TeV-scale supermultiplets in the vector-like 10+\bar{10} representation of SU(5), within the context of…
The Standard model of particle physics provides a successful theory to understand the experimental results of the electroweak and strong interactions. However, it does not have a satisfactory explanation for the hierarchy problem. Many…
Composite Higgs models generically predict the existence of heavy spin-1 resonances with the same quantum numbers as electroweak gauge bosons. The effective lagrangian description of these resonances is presented, pointing out the origin of…
LHC searches for BSM resonances in $l^+ l^-, \, jj, \, t\bar{t}, \gamma \gamma$ and $VV$ final states have so far not resulted in discovery of new physics. Current results set lower limits on mass scales of new physics resonances well into…
In extensions of two Higgs doublet models with vectorlike quarks and leptons the decays of new scalars or fermions can be altered by the presence of the other, depending on the hierarchy of new physics. If new fermions are heavier than…
The production of heavy mass resonances has been widely studied theoretically and experimentally. Several extensions of the standard model (SM) of particle physics, naturally give rise to a new resonance, with neutral electric charge,…